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草儿 — Tue, 04 Oct 2011 14:31:00 GMT

��Z��分析java应用的内存泄漏，使用thread dump往往解决不了问题。��用jstat【eg�Q?a target="_blank" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; font-family: 'Segoe UI', Calibri, 'Myriad Pro', Myriad, 'Trebuchet MS', Helvetica, Arial, sans-serif; color: #0071bb; outline-style: none; outline-width: initial; outline-color: initial; text-decoration: none; ">jstat -gcutil pid 1000 5】工��h��看运行的java应用的heap size,perm size ,survivor ratio�{�，当时你无法知道是什么对象把堆填满了�?/span>

什么是 Java heap dump

首先需要搞懂什么是java heap�Q�java heap是分配给实例�c�d��数组对象�q�行数据区，所有java�U�程在运行期间共享heap中的数据。Java heap dump相当于java应用在运行的时候在某个旉��点上打了个快照（snapshot�Q��?/span>

如果你不懂啥是snapshot�Q�点�?a target="_blank" style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; font-family: 'Segoe UI', Calibri, 'Myriad Pro', Myriad, 'Trebuchet MS', Helvetica, Arial, sans-serif; color: #0071bb; outline-style: none; outline-width: initial; outline-color: initial; text-decoration: none; ">�q�里

触发 Java heap dump

有以下方法出发heap dump

使用$JAVA_HOME/bin/jmap -dump来触发，eg�Q�jmap -dump:format=b,file=/home/longhao/heamdump.out
使用$JAVA_HOME/bin/jcosole中的MBean�Q�到MBean>com.sun.management>HotSpotDiagnostic>操作>dumpHeap中，点击 dumpHeap按钮。生成的dump文�g在java应用的根目录下面�?/span>
在应用启动时配置相关的参�?-XX:+HeapDumpOnOutOfMemoryError�Q�当应用抛出OutOfMemoryError时生成dump文�g�?/span>
使用hprof。启动虚拟机加入-Xrunhprof:head=site�Q�会生成java.hprof.txt文�g。该配置会导致jvm�q�行非常的慢�Q�不适合生��环境�?/span>

分析 Java heap dump

1�Q��用IBM HeapAnalyzer

IBM HeapAnalyzer是一�Ƒօ�费的JVM内存堆的囑�Ş分析工具�Q�它可以有效的列丑֠�的内存��用状况，帮助分析Java内存泄漏的原因�?/span>

下蝲解压后有一个ha413.jar�Q�执�? java -Xmx512m -jar ha413.jar /home/longhao/heapdump.out

执行�l�果如图所�C�：

2�Q�jhat

jhat�Q�Java Head Analyse Tool �Q?/a>是用来分析java堆的命��o�Q�可以将堆中的对象以html的�Ş式显�C�出来，包括对象的数量，大小�{�等�Q��ƈ支持对象查询语言OQL�Q�分析相关的应用后，可以通过http://localhost:7000来访问分析结果�?/span>

�C�Z��: $JAVA_HOME/bin/jhat -J-Xmx512m /home/longhao/dump.out

3�Q�Eclipse MemoryAnalyzer

Eclipse Memory Analyzer是一个快速�ƈ且功能强大的Java heap分析器，能够帮助你查扑ֆ�存泄漏和减少内存消耗。在File>Acquire Heap Dump>configure>HPROF jmap dump provider讄��一下分析应用的JDK�Q�点�ȝ��兛_��用列表来生成heap dump�q�分析�?br style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; font-family: 'Segoe UI', Calibri, 'Myriad Pro', Myriad, 'Trebuchet MS', Helvetica, Arial, sans-serif; " />

在socket�Q�nio中的有些API中，甌��的内存是直接向OS要的�Q�在堆中分析内存是查看不到的�Q�可以通过-XX:MaxDirectMemorySize=来设�|�应用向OS直接甌��的最大内存数�?/span>

草儿 2011-10-04 22:31 发表评论

java中Class.getResource用法

草儿 — Tue, 29 Sep 2009 11:43:00 GMT

摘要: 用JAVA获取文�g�Q�听似简单，但对于很多像我这��L��C�h来说�Q�还是掌握颇��，用�v来感觉颇深，大常最�l�常用的�Q�就是用JAVA的File�c�，如要取得 c:/test.txt文�g�Q�就会这��L��File file = new File("c:/test.txt");�q�样用有什么问题，�怿�大家都知道，��是路径��编码，对于JAVA�_��来说�Q�应用应该一�ơ成型，到处可用�Q��ƈ且从现实应用来讲�Q�最�l�生成的应用也会部��v到W... 阅读全文

草儿 2009-09-29 19:43 发表评论

OOME错误抛出原因

草儿 — Sat, 20 Sep 2008 03:20:00 GMT

OOME错误抛出原因�Q�排列以发生的可能性�ؓ据）�Q?/div>

1. Java Heap中无法申请到��_��的内存用于创建新的object�Q�JVM会抛出OOME错误

�Ҏ��异常发生的日志分析，有可能是因�ؓPOP3受信�Ӟ��发生死锁�Q�导致旧对象无法�?/div>

放，Java heap 内存��过最大分配内存，OOME抛出�?/div>

2. Native memory JVM正常�q�行�?JNI调用�W�三方库时分配内存。Native内存会在JVM�q�程所

需要的内存向系�l�申��P��如果JNI调用不能甌��到内存就会抛出OOME错误�?/div>

3. Process memory size 不够。这�U�可能性比较小�?/div>

草儿 2008-09-20 11:20 发表评论

草儿 — Sun, 16 Dec 2007 13:04:00 GMT

一、面向对象的�~�程概念

观察现实对象两个性质�Q�状态、行为�?/div>

面向对象的好处：模块化、隐藏信息�?/div>

�l�承�Q�子�c�M��父类�Q�超�c�）�l�承状态和行�ؓ�Q�子�c�d��以改变父�cȝ��状态和行�ؓ�?/div>

接口�Q�是无关对象用来�q�行彼此交互的设备；一个对象可以实现多个接口�?/div>

二、语�a�基础

变量

对象��它的状态存储在变量中；变量是一个由标识�W�命名的数据��V�?/div>

声明变量的�Ş式：<�c�d��> <名称>

JAVA语言两大数据�c�d��

原始�c�d��数据(基本数据�c�d��)、引用类型�?/div>

原始�c�d��数据是不能再分解的数据类�?8�U�：byte、short、int、long、float、double、char、boolean)�Q�数据在作�ؓ函数参数是以“传�?#8221;方式工作的；

整数 byte�Q?字节长的整数�Q?位有�W�号的二�q�制补码整数

short�Q�短整数�Q?6位有�W�号的二�q�制补码整数

int�Q�整敎ͼ�32位有�W�号的二�q�制补码整数

long�Q�长整数�Q?4位有�W�号的二�q�制补码整数

实数 flat�Q�单�_�ֺ��点敎ͼ�32位IEEE 754��点�?/div>

double�Q�双�_�ֺ��点敎ͼ�64位IEEE 754��点�?/div>

其他�c�d�� char�Q�单一Unicode字符�Q?6位Unicode字符

boolean�Q�布��?true或false)�Q?�?1�?8位空��_��1位数�?

引用�c�d��包括�c?class)、接�?interface)、数�l?array)。引用类型有时也�U�复合类型，它是可以分解为基本类型的数据�c�d��Q�其数据在作为函数参数时是以“传址”的方式工作的。与原始�c�d��相对�Q�引用类型变量的值是对由此变量代表的一个值或一�l�值的引用(也就是地址)�?/div>

如：

原始�c�d�� int a = 3; //“a”表示变量名称�Q?#8220;3”表示变量��|��如果写成“final int a = 3;”�Q?#8220;final”表示不可改变��|��所以这里的3(变量�?不可�?/div>

引用�c�d�� Staing b = "Hello Java"; //“b”表示引用名称�Q?#8220;Hello Java”表示字��Q串数�l?/div>

��程控制语句

循环 while、do - while、for

判断 if - else、switch - case

异常处理 try – catch – finally、throw

分支 break、continue、label :、return

循环�Q?/div>

while和do – while语句�Q�While语句用于在条件保持�ؓtrue时反复执行一个代码块�Q?/div>

do – while语句的代码块中的语句臛_��被执行一�ơ�?/div>

for语句�Q?/div>

for语句提供一�U��P代某个范围内的值的紧湊方式�?/div>

判断�Q?/div>

if – else 语句�Q�if语句使程序能够根据某些条件有选择地执行其他语句；

switch语句用于�Ҏ��一个整数表辑ּ�有条件的执行语句�Q?/div>

注意�Q�必��要有明��的break语句�Q�否则，��程控制��一个接一个的�l�过后面的case语句

比较if语句和switch语句(if语句可以用于�Ҏ��某范围的值或条�g�q�行判断;switch语句只用于根据单个整数��D��行判�?�?/div>

异常处理语句�Q?/div>

当程序发生错误时�Q�程序会抛出一个异常，�E�序的正常流�E�被中断�Q?/div>

分支语句�Q�break、continue语句可以和标�{�语句一起��用，也可以没有标�{�；

标签是放在一个语句前的标识符�Q�标识符后跟一个冒��P��

continue 语句�Q�continue语句用于跌��for、while、do – while循环的当前�P代；

return 语句�Q�返回一个��|��不返回倹{�?/div>

三、对象基��和简单数据结�?/strong>

创徏对象�Q�声明一个变量来引用变量�Q�对对象�q�行实例�?构造器)�Q?/div>
用new操作�W�和构造器从类创徏对象�?/div>

两种方式使用一个对象：引用一个对象的变量�Q�调用对象的�Ҏ��?/div>

字符和字�W�串

JAVA�q�_��包含三个用于处理字符数据的类�Q?/div>
Character�Q�包含单个字�W��|��定义了一些可用于操作和检查单字符数据的方�?Character�cȝ��对象实例包含单个字符��|��可用Character对象替代基本�c�d��char)�?/div>
String�Q�这个类用于处理由多个字�W�组成的不可改变的数据�?/div>
StringBuffer�Q�存储和操作由多个字�W�组成的可改变的数据�?/div>

字符串和字符串缓冲区

String�Q�不能改变自�w�的倹{�?/div>
StringBuffer�Q�用于将被修改的字符丌Ӏ?/div>

得到字符串或字符串缓冲区的长�?/strong>

length�Ҏ��Q�返回字�W�串或字�W�串�~�冲��Z��包含的字�W�数�?/div>
capacity�Ҏ��Q�StringBuffer�Ҏ��Q�返回分配给字符串缓冲区的空间量�Q�而不是被使用的空间量�?/div>
String�c�L��有capacity�Ҏ��Q�因为字�W�串不能改变�?/div>

通过索引从字�W�串或字�W�串�~�冲区得到字�W?/strong>

charAt(int)�Ҏ��Q�得到字�W�串或字�W�串�~�冲区某索引位置上的字符�?/div>
注意�Q�第一个字�W�串的烦引�ؓ0�Q�最后一个字�W�的索引为length – 1�Q?/div>
subString(int), subString(int,int)�Q�从字符串或字符串缓冲区中得到多个字�W��?/div>

在字�W�串中搜索字�W�或子字�W�串

String�c�L��供了两个讉K��器方法：indexOf �Ҏ��从字�W�串的开头向前搜索；lastIndexOf �Ҏ��从字�W�串的末��֐�后搜索；

StringBuffer�c�M��支持indexOf和lastIndexOf�Ҏ��?/div>

操作字符�?/strong>

String�c�L��几个�Ҏ��看�v来可以修改字�W�串。当�Ӟ��字符串是不能被修改的�Q�所以，�q�些�Ҏ��实际上是创徏�q�返回包含结果的另一个字�W�串�?/div>

修改字符串缓�?/strong>

字符串缓冲是可以修改的，StingBuffer提供了几个用于修改字�W�串�~�冲区的数据的方法；

如果修改字符串缓冲区的操作造成字符串缓冲区的大��超出它的当前容量，那么字符串缓冲区会自动分配更多的内存�?/div>

字符串和�~�译�?/strong>

�~�译器在很多地方自动的��用String和StringBuffer�c�L��处理字符串直接值和字符串连接；

�~�译器�ؓ它遇到的每个字符串直接��D��动创��Z��个新的String对象�Q?/div>
可以使用+操作�W�连接字�W�串�?/div>

四、类和��?/strong>

实现�l�承�Q?/strong>extends关键�?/div>

为类提供构造器

构造器用于初始化类的新对象�Q�构造器不是�Ҏ��Q�没有返回类型；构造器的声明中可以使用以下讉K��说明�W�：

–      private

–      protected

–      public

–      无说明符

��信息传递给�Ҏ��或构造器

参数�c�d��Q?/div>
参数名称�Q?/div>
按��g��递：参数是原始类型，�Ҏ��不能改变其��|��参数是引用类型，�Ҏ��不能改变其引用，但可以改变引用对象的倹{�?/div>

从方法返回�?/strong>

在方法声明中声明�Ҏ��的返回类型；eturn语句�q�回值的数据�c�d��必须匚w��Ҏ��声明的返回类型；�Ҏ��可以�q�回原始�c�d��Q�也可以�q�回引用�c�d��?strong>

使用this关键�?/strong>

在实例方法或构造器中，this引用当前对象�Q�也��是被调用的�Ҏ��或构造器所属的对象�Q�在构造器中，�q�可以��用this关键字调用相同类中的另一个构造器�?/div>

控制对类成员的访�?/strong>

讉K��说明�W�决定其他类是否可以使用某个成员或调用某个方法。Java�~�程语言支持四种用于成员变量和方法的讉K��U�别�Q�private、protected、public�?如果没有指定)package�?strong>

讉K��U�别

Private�Q�类

无说明符�Q�类、包

Protected�Q�类、包、子�c?/div>
Public�Q�类、包、子�c�R��所有类

实例和类成员的初始化

可以在声明的同时�q�行初始化，但是有一些限�Ӟ��

–      必须以一个赋��D��句表辑ֈ�始化方式

–      初始化表辑ּ�不能调用��M��被声明�ؓ抛出非运行时异常的方�?/div>
–      如果初始化表辑ּ�调用一个抛��行时异常的方法，那么它不能进行错误恢�?/div>
使用静态初始化块初始化�c�L��员；

实例成员的初始化�?/div>

覆盖和隐藏方�?/strong>

覆盖�Q�override�Q�（实例�Ҏ��Q�：

–      子类中的个实例方法与��类中的实例�Ҏ��h��相同的标记和�q�回�c�d��

–      �Ҏ��的标讎ͼ�名称�Q�参数数量、参数类�?/div>
–      覆盖�Ҏ��可以��h��不同的throws子句

–      覆盖�Ҏ��的访问说明符允许讉K��限制只能比被覆盖�Ҏ��的多

–      子类不能覆盖��类中声明�ؓfinal的方�?/div>
–      子类必须覆盖��类中声明�ؓabstract的方法，否则子类本��n必须是抽象的

覆盖和重载（overload�Q�；

覆盖和隐藏（�c�L��法）�?/div>

隐藏成员变量

在类中，如果一个成员变量与��类中的成员变量同名�Q�即使它们的�c�d��不同�Q�，那么它隐藏超�c�L��员变量；

在子�c�M��Q�不能通过��单名�U�引用超�c�M��的成员变量，而是必须通过super讉K��它；

代码可读性差�Q�不��隐藏成员变量�?/div>

使用super

使用super调用被覆盖的�Ҏ��Q��用super调用被隐藏的成员变量�Q��用super在构造器中调用超�cȝ��构造器�?/div>

使用Object的后�?/strong>

每个�c�都是Object�cȝ��直接后代或间接后代；

Object�c�d��义了所有类都必��L��的基本状态和行�ؓ�Q?/div>
–      clone

–      equals和hashCode

–      finalize

–      toString

–      getClass

–          notify、notifyAll和wait

�~�写final�c�d��Ҏ��

��类声明为final�Q�即�c�M��能被子类化：

–      通过防止�pȝ��被改版来提高�pȝ��的安全�?/div>
–      ��Z��设计上的原因�Q�某些类不需要子�c?/div>
final�Ҏ��Q?/div>
–          在方法声明中使用final关键字表�C��个方法不能被子类覆盖

�~�写抽象�c�d��Ҏ��

抽象�c�：

–      表示一个抽象的概念�Q�不应该被实例化

–      abstract关键�?/div>
抽象�Ҏ��Q?/div>
–      没有实现的方法，允许子类提供�q�些�Ҏ��的实现细�?/div>
–          如果抽象�c�d��包含抽象�Ҏ��Q�那么它应该被定义成接口

创徏�cȝ��结

�cȝ��定义有两个部分：

–     �c�d��?/div>
–     �c�M��Q�成员变量、方法、构造器

讉K��说明�W�——控制对成员变量和方法的讉K��方式�Q?/div>
�c�d��量、类�Ҏ��Q�static�Ҏ��关键�?/div>
实例成员、实例方�?/div>

五、接口和�?/strong>

实现接口�Q?/strong>implements关键�?/div>

�c�d��以实现多个接�?implements关键字后面跟以逗号分隔的接口列表；

如果有extends关键�?implements子句应该在extends子句的后面；

�c�要么必需实现接口及其��接口中的所有方�?要么�c�d��被声明为抽象的�Q?/div>
�c�M��的方法标�?名称和参数列�?必须匚w��接口中的�Ҏ��标记�?/div>

��接口作为类型��?/strong>

在定义了一个新接口�?��是在定义一个新的引用数据类型；

定义可一用接�?实例化是必须用类�?/div>

接口不能改变

从语法的角度�?接口可以被改变；

从设计的角度�?一个已�l�在�pȝ��中被�q�泛使用的接�?不能��L��被改变；

如果改变了接�?实现原接口的�c�都��无法工作；

应该��可能的考虑接口所提供的方法；

如果要改变接�?用��承的方式定义新的接口�?/div>

接口��结

接口定义了一�U�功能描�q?定义了对象之间进行通讯的协议；

接口定义由接口声明和接口体组成；

接口包含一�l�方法的声明,但没有方法的实现�Q?/div>
实现接口的类必须实现接口中声明的所有方法；

接口名称可以作�ؓ数据�c�d��使用�?/div>

创徏和��用包

创徏包：

–     ��package语句作�ؓ�c�L��接口源代码文件中的第一条语�?/div>
–     �c�L��接口的源代码和类文�g的�\径名与包的名�U�相对应

使用另一个包中的接口或类�Q?/div>
–     �c�L��接口的限定名

–     导入�c�L��接口

–     导入�c�L��接口所在的整个�?/div>

六、��用异常处理错�?/strong>

什么是异常�Q�异�?exception)是在�E�序执行期间中断指��o的正常流�E�的事�g�?/div>

try�?/strong>

try {

       statements

}

statements是包含一个或多个可能抛出异常的语句�?/div>

catch�?/strong>

每个catch块是一个异常处理器�Q�它处理由其参数指定的异常类�?/div>
try{

       ......

} catch(ExceptionType name) {

       ……

} catch (ExceptionType name) {

       ……

}

finally�?/strong>

finally块是可选的�Q�它提供一�U�机�Ӟ��其目的是无论try块中是否发生异常都确保进行清理工作；

无论是否发生异常�Q�都会执行finally块中的代码�?/div>

throw语句

throw语句需要一个参敎ͼ�一个可抛出的（Throwable�Q�对象；可抛出对象是Throwable�cȝ��子类�?/div>

Throwable�c�d��其子�c?/strong>

Throwable�c�L��两个直接子类�Q?/div>
–     Error

–     Exception

Error�Q?/div>
–     JAVA虚拟机的动态链接故障或其它“��?#8221;故障�Q�一般的�E�序不应该捕获Error�Q�也不能抛出Error

Exception�Q?/div>
大多数程序抛出�ƈ捕获从Exception�c�L��生的对象。Exception表示发生了一个问题，但�ƈ不是严重的系�l�问题。你写的多数�E�序��抛出�ƈ捕获Exception(而不是Error)�?/div>
–     Exception表示发生了一个问题，但�ƈ不是严重的系�l�问�?/div>
–     Exception的不同子�c�表�C�可能发生的各种异常

异常的优点：��错误代码与“常规”代码分离�Q�将错误沿调用堆栈向上传递；寚w��误类型进行分�l�和区分�?/div>

异常的小�l?/strong>

�E�序可以使用异常表明发生了错误；

�E�序可以使用throw语句抛出异常�Q?/div>
异常是一个对象（Throwable的子�c�）�Q?/div>
�E�序可以使用try、catch语句finally来捕获异常：

–     try语句标识出可能发生的异常

–     catch语句标识出异常处理器

–          finally代码块不论抛出异�怸�否都会被执行�Q�适用于清理工�?/div>

七、线�E�：同时执行多个��d��

只要用到�U�程��必��ȝ��承或接口�Q?/strong>Thread�?/strong>

只要用到�U�程��必��要�?/strong>run�Ҏ��?/strong>

什么是�U�程�Q?/strong>

–     �U�程是程序内的一个单一的顺序控制流�E?/div>
–     �U�程本��n不是�E�序�Q�不能单独运行，它在一个程序内�q�行

–     多个�U�程可以同时�q�行�Q�在一个程序内执行不同的�Q�?/div>

定制�U�程�?/strong>run�Ҏ��

run�Ҏ��执行�U�程的工作；

run�Ҏ��实现了线�E�的�q�行行�ؓ�Q?/div>
run�Ҏ��可以做�Q何可以用语句实现的事�?/div>

为线�E�提�?/strong>run�Ҏ��Q?/strong>

–     �l�承Thread�c�，�q�覆盖run�Ҏ��

–     实现Runnable接口

�?/strong>Thread�c�进行子�c�d��和覆�?/strong>run

public class SimpleThread extends Thread {

       public SimpleThread(String str) {

           super(str);

       }

       public void run() {

           for (int i = 0; i < 10; i++) {

               System.out.println(i + " " + getName());

               try {

                   sleep((long)(Math.random() * 1000));

               } catch (InterruptedException e) {}

           }

           System.out.println("DONE! " + getName());

       }

}

实现Runnable接口�Q?/strong>如果一个类已经�l�承了另一个类�Q�那么要惛_��现线�E�就必须实现Runnable接口�?/div>

在线�E�中�l�果是随��Z�生的�Q�如果想锁定对象��p��使用Synchronized关键字意思�ؓ锁定�Ҏ��所有在的对象。在对象被解锁前�Q�其他线�E�不能调用相同对象上的被同步的方法。意思�ؓ执行一个对象后�Ȁ�z�d��一个对象，自��n暂时睡眠�Q�等待另一个对象执行完毕，在执行下一步，反复如此�?/div>

八、IO�Q�读和写

如何使用��道��：��道用于��一个线�E�的输出�q�接到另一个线�E�的输入

如何��装��：��经常被以下的这�U��Ş式封装�v来，以便�l�合许多��的各种功能

对象的串行化�Q?/strong>Java.io包中的两个流——ObjectInputStream和ObjectOutputStream是字节流�Q�他们的工作与其他输入和输出��类伹{��但他们的特�D�之处在于它们可以读写对象�?/font>

对对象进行串行化�Q?/strong>如果��一个不能串行化的对象传递给writeObject�Ҏ��Q�那么它抛出一个NotSerializable Exception。对象只能在它的�c�d��C��Serializable接口的情况下被串行化�?/font>

为类提供对象串行化：只有在对象的�c�d��C��Serializable接口情况下，对象才是可串行化的。所有，如果惌��对你的类的实例进串行化，�q�个�c�d��d��现Serializable接口。Serializable接口是一个空接口�Q�也��是��_��他不包含��M��Ҏ��声明�Q�它的作用只是表明这个类的对象可以被串行化�?/font>

I/O复制��程�?Copy.java)�Q�如下：

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
//以上是此�E�序用到的IO�cȝ��包，也可以用“import java.io.*”

public class Copy {
       public static void main(String[] args) throws IOException {
File inputFile = new File("D:\\temp\\HelloWorld.java"); //目标文�g路径�Q�JAVA中�\径地址只能�?#8220;\\”�?#8220;/”不能使用“\”
File outputFile = new File("D:\\temp\\OutAgain.java"); //复制后新文�g保存路径

           FileReader in = new FileReader(inputFile);
           FileWriter out = new FileWriter(outputFile);
           int c;

           while ((c = in.read()) != -1) //一直��@环到0表示已经复制完毕�Q�所以这里��用不�{�于�?
              out.write(c);

           in.close(); //关闭��L��件对�?br />            out.close(); //关闭写文件对�?br />        }

草儿 2007-12-16 21:04 发表评论

草儿 — Wed, 24 Oct 2007 02:14:00 GMT
     摘要: java.util.concurrent 包含许多�U�程安全、测试良好、高性能的�ƈ发构建块。不客气地说�Q�创�?java.util.concurrent 的目的就是要实现 Collection 框架�Ҏ��据结构所执行的�ƈ发操作。通过提供一�l�可靠的、高性能�q�发构徏块，开发�h员可以提高�ƈ发类的线�E�安全、可伸羃性、性能、可��L��和可靠性�?如果一些类名看��h��怼��Q�可能是因�ؓ java.util.concurr...  阅读全文

草儿 2007-10-24 10:14 发表评论

草儿 — Fri, 28 Sep 2007 06:24:00 GMT


import java.io.IOException;

class MyNode {
  private int iData;

  public MyNode(int key) {
    iData = key;
  }

  public int getKey() {
    return iData;
  }

}

public class Heap {
  private MyNode[] heapArray;

  private int maxSize;

  private int currentSize; // number of items in array

  public Heap(int mx) {
    maxSize = mx;
    currentSize = 0;
    heapArray = new MyNode[maxSize];
  }

  public MyNode remove()
  {
    MyNode root = heapArray[0];
    heapArray[0] = heapArray[--currentSize];
    trickleDown(0);
    return root;
  }

  public void trickleDown(int index) {
    int largerChild;
    MyNode top = heapArray[index];
    while (index < currentSize / 2)
    {
      int leftChild = 2 * index + 1;
      int rightChild = leftChild + 1;
      // 扑ֈ�最大的子节�?/font>
      if (rightChild < currentSize
          &&
          heapArray[leftChild].getKey() < heapArray[rightChild]
              .getKey())
        largerChild = rightChild;
      else
        largerChild = leftChild;

      if (top.getKey() >= heapArray[largerChild].getKey())
        break;

      heapArray[index] = heapArray[largerChild];
      index = largerChild;
    }
    heapArray[index] = top;
  }

  public void displayHeap() {
    int nBlanks = 32;
    int itemsPerRow = 1;
    int column = 0;
    int currentIndex = 0;
    while (currentSize > 0)
    {
      if (column == 0)
        for (int k = 0; k < nBlanks; k++)
          System.out.print(' ');
      System.out.print(heapArray[currentIndex].getKey());

      if (++currentIndex == currentSize) // 判断是否输出�l�束
        break;

      if (++column == itemsPerRow) // 是否到达行尾?
      {
        nBlanks /= 2;
        itemsPerRow *= 2;
        column = 0;
        System.out.println();
      } else
        for (int k = 0; k < nBlanks * 2 - 2; k++)
          System.out.print(' '); // 输入�I�白
    }
  }

  public void displayArray() {
    for (int j = 0; j < maxSize; j++)
      System.out.print(heapArray[j].getKey() + " ");
    System.out.println("");
  }

  public void insertAt(int index, MyNode newNode) {
    heapArray[index] = newNode;
  }

  public void incrementSize() {
    currentSize++;
  }

  public static void main(String[] args) throws IOException {
    int size, i;

    size = 100;
    Heap theHeap = new Heap(size);

    for (i = 0; i < size; i++) {
      int random = (int) (java.lang.Math.random() * 100);
      MyNode newNode = new MyNode(random);
      theHeap.insertAt(i, newNode);
      theHeap.incrementSize();
    }

    System.out.print("Random: ");
    theHeap.displayArray();
    for (i = size / 2 - 1; i >= 0; i--)
      theHeap.trickleDown(i);

    System.out.print("Heap:   ");
    theHeap.displayArray();
    theHeap.displayHeap();
    for (i = size - 1; i >= 0; i--) {
      MyNode biggestNode = theHeap.remove();
      theHeap.insertAt(i, biggestNode);
    }
    System.out.print("Sorted: ");
    theHeap.displayArray();
  }
}

草儿 2007-09-28 14:24 发表评论

草儿 — Fri, 28 Sep 2007 06:10:00 GMT

import java.sql.Connection; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.Properties; import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.NamingException; import javax.sql.ConnectionPoolDataSource; import javax.sql.PooledConnection; public class MainClass {   public static void main(String[] args) {     Connection connection = null;     Statement statement = null;     ResultSet resultSet = null;     try {       connection = getConnection();       // 操作�q�接       statement = connection.createStatement();       String selectEmployeesSQL = "SELECT * FROM employees";       resultSet = statement.executeQuery(selectEmployeesSQL);       while (resultSet.next()) {         printEmployee(resultSet);       }     } catch (Exception e) {       e.printStackTrace();     } finally {       if (resultSet != null) {         try {           resultSet.close();         } catch (SQLException e) {         } // nothing we can do       }       if (statement != null) {         try {           statement.close();         } catch (SQLException e) {         } // nothing we can do       }       if (connection != null) {         try {           connection.close();         } catch (SQLException e) {         } // nothing we can do       }     }   }   private static Connection getConnection() throws NamingException, SQLException {     InitialContext initCtx = createContext();     String jndiName = "HrDS";     ConnectionPoolDataSource dataSource = (ConnectionPoolDataSource) initCtx.lookup(jndiName);     PooledConnection pooledConnection = dataSource.getPooledConnection();     return pooledConnection.getConnection(); // 从池中得到连�?/font>   }   private static InitialContext createContext() throws NamingException {     Properties env = new Properties();     env.put(Context.INITIAL_CONTEXT_FACTORY, "com.sun.jndi.rmi.registry.RegistryContextFactory");     env.put(Context.PROVIDER_URL, "rmi://localhost:1099");     InitialContext context = new InitialContext(env);     return context;   }   private static void printEmployee(ResultSet resultSet) throws SQLException {     System.out.print(resultSet.getInt("employee_id")+", ");     System.out.print(resultSet.getString("last_name")+", ");     System.out.print(resultSet.getString("first_name")+", ");     System.out.println(resultSet.getString("email"));   } }

草儿 2007-09-28 14:10 发表评论

草儿 — Wed, 19 Sep 2007 02:34:00 GMT
在Java中，数组不能动态重讑֤��。一个可替代�Ҏ��是��?a goog_ds_charindex="31">java.util.ArrayList (或�?a goog_ds_charindex="56">java.util.Vector)代替使用原始数组�Q�array�Q�。另一�U�解��x��案是用一个不同大��的数组重设数组�Q�将旧数�l�内�Ҏ��贝到新的数组。下面做了个演示�E�序实现�W�二�U�方案，�~�写了个通用函数rsizeArray (参数)来实现此功能�Q?

/**
* 使用一个新大小重设数组�Q��ƈ拯��旧数�l�的内容到新数组
* @param oldArray 旧数�l�被重设
* @param newSize 新数�l�大��?br goog_ds_charindex="378" /> * @return �q�回带同样内容的新数�l?br goog_ds_charindex="433" /> */
private static Object resizeArray (Object oldArray, int newSize){
int oldSize = java.lang.reflect.Array.getLength(oldArray);
Class elementType = oldArray.getClass().getComponentType();
Object newArray = java.lang.reflect.Array.newInstance(
elementType,newSize);
int preserveLength = Math.min(oldSize,newSize);
if (preserveLength > 0)
System.arraycopy (oldArray,0,newArray,0,preserveLength);
return newArray;
}

// resizeArray()��试用例
public static void main (String[] args) {
int[] a = {1,2,3};
a = (int[])resizeArray(a,5);
a[3] = 4;
a[4] = 5;
for (int i=0; i System.out.println (a[i]); }

那二�l�数�l�如何重讑֤��呢�Q?很简单，��是处理数组的数�l�呀�Q?/strong>

要想重设二维数组�Q?em>resizeArray�Ҏ��必须处理外部数组和所有嵌套数�l�，如下例：

int a[][] = new int[2][3];
//...
a = (int[][])resizeArray(a,20);
// 新数�l�是[20][3]
for (int i=0; i if (a[i] == null)
a[i] = new int[30];
else a[i] = (int[])resizeArray(a[i],30);
}
// 新数�l�是[20][30]

草儿 2007-09-19 10:34 发表评论

草儿 — Sat, 15 Sep 2007 09:56:00 GMT
http://www.infoq.com
http://www.theserverside.com
http://www.javablogs.com
http://www.java.net
http://www.javasoft.com
http://blogs.sun.com
   之（重要�Q?br />    http://blogs.sun.com/roumen/
   http://blogs.sun.com/geertjan/
   http://blogs.sun.com/theaquarium/
http://www.ibm.com/developerworks
http://www.onjava.com/
http://www.developer.com/java/
http://www.javaworld.com/
http://www.java.com/
http://www.netbeans.org/kb/index.html
http://www.eclipse.org
http://www.oracle.com/technology/tech/java/index.html
http://www.javaranch.com
http://www.javablackbelt.com
http://www.jugcologne.org
http://www.dzone.com

草儿 2007-09-15 17:56 发表评论

Java Annotation手册

草儿 — Thu, 06 Sep 2007 11:11:00 GMT
     摘要:
Annotation 提供了一条与�E�序元素兌��M��信息或者�Q何元数据�Q�metadata�Q�的途径。从某些斚w��看，annotation��像修饰�W�一栯��使用�Q��ƈ应用于包、类型、构造方法、方法、成员变量、参数、本地变量的声明中。这些信息被存储在annotation的“name=value”结构对中�?annotation�c�d��是一�U�接口，能够通过java反射API的方式提供对其信息的讉K��?
  阅读全文

草儿 2007-09-06 19:11 发表评论

什么是JMX?

草儿 — Mon, 03 Sep 2007 14:26:00 GMT

JMX(Java Management Extensions)是一个�ؓ应用�E�序植入��理功能的框架。JMX是一套标准的代理和服务，实际上，用户可以在�Q何Java应用�E�序中��用这些代理和服务实现��理�?

JMX的前�w�是JMAPI�?

JMX致力于解军_��布式�pȝ��理的问题，因此�Q�能够适合于各�U�不同的环境是非帔R��要的。�ؓ了能够利用功能强大的Java计算环境解决�q�一的问题，Sun公司扩充�?a class="wikipage" >Java基础�c�d��Q�开发了专用的管理类库�?

JMX是一�U�应用编�E�接口，可扩充对象和�Ҏ��的集合体�Q�可以用于跨��一�p�d��不同的异构操作系�l��^台、系�l�体�pȝ��构和�|�络传输协议�Q�灵�zȝ��开发无�~�集成的�pȝ��、网�l�和服务��理应用它提供了用户界面指导、Java�c�d��开发集成系�l�、网�l�及�|�络��理应用的规范�?

��理对象是JMX应用�E�序的核心。JMX�l�构包括�Q�支持Java的Web��览器用��h��口，��理�q�行模块ARM(Admin Runtime Module)和应用。这三个部�g之间通过RMI�Q�Remote Method Invocation�Q�进行通信。这里需要说明的是，RMI是��得一个Java虚拟机（JVM�Q�上�q�行的程序可以调用远�E�服务器上另一�?a class="wikipage" >JVM�ȝ��对象�?

用户接口用来发布��理操作�Q�这些操作可以间接的通过��览器或通过单独的应用程序来�Ȁ发。管理运行模块用来给应用提供实例化的��理对象。它包括Agent对象接口�Q�通知接口和被��数据接口。应用指的是那些被管讑֤�单元�?

JMX是一个完整的�|�络��理应用�E�序开发环境，它同时提供了�Q�厂商需要收集的完整的特性清单，可生成资源清单表��|��囑�Ş化的用户接口�Q�访�?a class="editpage" title="Create 'SNMP'" >SNMP的网�l�API�Q�主机间�q�程�q�程调用�Q�数据库讉K��Ҏ��?

JMX�q�一��d��的管理基��l�构�Q��h值在于对被管理资源的服务实现了抽象，提供了低层的基本�c�集合，开发�h员在保证大多数的公共��理�cȝ��完整性和一致性的前提下，�q�行扩展以满��特定网�l�管理应用的需要�?

JMX注重于构造管理工��L��软�g框架�Q��ƈ��量采用已成熟的技术�?

JMX体系被分成三个层��?

表现�?
代理�?
分布式服务层

表现�?

表现层定义的是JMX可管理资源所在的层�?

�q�些已管理的资源可以�~�写或封装�ؓMBean�?

MBean分�ؓ四种�c�d��Q?标准、动态、开放、模�?

代理�?

定义的是MBean向应用程序施加管理的层。包括MBean服务器和代理服务的定义。还臛_��包括一个协议适配器或�q�接器�?

代理的组成：。一个MBean服务�?。要��理的MBean 。作为MBean实现的代理服�?。至��一个协议适配�?

MBean

在JMX中，最��的可管理单元是MBean�?

MBean不是一个真正的接口和类�Q�而是必须准��@的设计模式以��保资源是一个兼容的MBean�?

MBean的激�z�L��?

invoke()�Ҏ��是管理应用程序用于激�z�MBean的方法的手段�?invoke()�Ҏ��有三个参敎ͼ�分别是方法的名称、表�C�属性的对象数组和描�q�方法签名的一个字�W�串数组。它与��?a class="editpage" title="Create 'JavaReflection'" >Java Reflection Api �Ȁ�z�L��法的方式�c�M��?

Notification(通知)模型�Q?

MBean的通知模型�c�M��与Java事�g的监听器模型�?MBean或管理应用程序可以作为MBean事�g的监听器注册�?通知支持�׃��个基本的概念�l�成�Q�即�q�播器和监听器�?

MBean服务�?

MBean服务器用于注册可��理的MBean�?

所有对MBean的请求或查询都是通过MBean服务器实施的�?

代理服务

代理服务是一些特�D�的函数�Q�代理把�q�些服务提供�l�MBean�Q�这些代理服务独立于��M��MBean�?

一个代理可以提供四�U�主要的服务�Q?

动态装载：允许代理通过下蝲�q�个Bean的类动态实例化MBean�Q�这与装载applet的方式类伹{�?

JMX使用m-let�q�个标记指定期望动态装载的MBean的位�|��?

监控�Q�允�总�理通知有关的监听器监控一个MBean的属性值的变化

JMX允许使用三种基本�c�d��的监控程�?(1)CounterMonitor�Q�该�E�序可以观察�c�d��斚w��的变化，比如Byte�c�M��或Integer�c�d�� (2)GaugeMonitor�Q�该�E�序可以观察�c�d��斚w��的变化，比如Byte�c�M��或Integer�c�d��Q�还可以在到达上下阀值时�q�行报告�?(3)StringMonitor�Q�该�E�序可以观察java.lang.String�c�d��的变化�?

计时器：允许预设的时间间隔发送通知�Q�可以作��Z��个调度程�?
关系�Q�允许创建和�l�护MBean之间的关�p?

分布式服务层

包含协议适配器和�q�接器两�U�类型的�l��g�Q�通过它们�q�接到外部的应用�Q�如RMI��理应用、基于浏览器的管理控制等

协议适配器和�q�接�?

协议适配器是代理与管理客户通信的手�D�，每个通信的协议都可能不同�?

它们都是��理客户与MBean交互的方式�?

JMX的好�?

可减��对JAVA应用实施��理的投�?
提供了一个可伸羃的管理框�?
集成现有的管理方案：如：WBEM�Q�SNMP�Q�TMN
使用现有的标准JAVA技�?
能��用未来的一些管理概念：如Jini�q�接技术、通用��x��即用、服务定位协�?Service Location Protocol)
只定义了一些可以访问的接口

相关资源�Q?/p>

JMX相关框架
MC4J
XMOJO
MX4J
JFoxMX
JMX4Ant
Panoptes
EJTools JMX Browser
jManage

草儿 2007-09-03 22:26 发表评论

�?侯捷谈Java反射机制

草儿 — Wed, 29 Aug 2007 03:24:00 GMT
     摘要: 摘要 Reflection 是Java被视为动态（或准动态）语言的一个关键性质。这个机制允许程序在�q�行旉��过Reflection APIs取得��M��一个已知名�U�的class的内部信息，包括其modifiers�Q�诸如public, static �{�等�Q�、superclass�Q�例Object�Q�、实��C��interfaces�Q�例如Cloneable�Q�，也包括fields和methods的所有信息，�q�可于运...  阅读全文

草儿 2007-08-29 11:24 发表评论

草儿 — Sat, 25 Aug 2007 15:16:00 GMT

sourceforge http://www.sourceforge.net
java.net http://www.java.net

www.eclipse.org

www.opensource.org

http://strutstestcase.sourceforge.net (StrutsTestCase是基�?span lang=EN-US>Junit的一个方便测�?span lang=EN-US>struts框架的测试框�?

Lomboz http://www.objectlearn.com/index.jsp (J2EE plugin for Eclipse)
htmlArea http://sourceforge.net/projects/itools-htmlarea/ (所见即所得的在线HTML�~�辑�?
XmlBuddy http://www.xmlbuddy.com/ (XML Editor plugin for Eclipse)
JFreeChart http://www.jfree.org/ (用于生成图表的项�?
EclipseME http://eclipseme.sourceforge.net/ (J2ME Developmnt Plugin for Eclipse)
mvnForum http://sourceforge.net/projects/mvnforum/ (论坛)
jChatBox http://www.javazoom.net/index.shtml (用servlet实现的WEB聊天引擎)
POI http://jakarta.apache.org/poi/index.html (用于处理Excel,WORD�{�文档的��目)
FileUpload http://jakarta.apache.org/commons/fileupload/ (用于处理HTTP文�g上传得项�?
PDFBox http://sourceforge.net/projects/pdfbox/ (处理PDF文档的项�?
Lucene http://jakarta.apache.org/lucene/index.html (搜烦引擎)
Digester http://jakarta.apache.org/commons/digester/ (处理XML信息的项�?
DBCP http://jakarta.apache.org/commons/dbcp/ (数据库连接池)
AXIS http://ws.apache.org/axis/ (WebService 的实现框�?
Jetspeed http://portals.apache.org/jetspeed-1/ (Portal)
HSQLDB http://sourceforge.net/projects/hsqldb/ (Im memory Database Engine)
CEWOLF http://sourceforge.net/projects/cewolf/ (一套标�{�ֺ�实现Web报表,使用的是jFreeChart引擎)
Struts Menu http://sourceforge.net/projects/struts-menu/ (��Z��Struts的Web菜单��目)
htmlparser http://sourceforge.net/projects/htmlparser/ (用于解析HTML信息的项�?
Mondrian http://sourceforge.net/projects/mondrian/(Open Source OLAP Database)
ProGuard http://sourceforge.net/projects/proguard/(Java的�؜淆器)
InfoGlue http://sourceforge.net/projects/infoglue/ (J2EE 内容��理�pȝ��)
JPivot http://sourceforge.net/projects/jpivot/ (��Z��WEB的OLAP 展现)
http://java-source.net/

(5)几个常用JAVA开源项目的地址荟萃:
Lomboz http://www.objectlearn.com/index.jsp (J2EE plugin for Eclipse)
htmlArea http://sourceforge.net/projects/itools-htmlarea/ (所见即所得的在线HTML�~�辑�?
XmlBuddy http://www.xmlbuddy.com/ (XML Editor plugin for Eclipse)
JFreeChart http://www.jfree.org/ (用于生成图表的项�?
EclipseME http://eclipseme.sourceforge.net/ (J2ME Developmnt Plugin for Eclipse)
mvnForum http://sourceforge.net/projects/mvnforum/ (论坛)
jChatBox http://www.javazoom.net/index.shtml (用servlet实现的WEB聊天引擎)
POI http://jakarta.apache.org/poi/index.html (用于处理Excel,WORD�{�文档的��目)
FileUpload http://jakarta.apache.org/commons/fileupload/ (用于处理HTTP文�g上传得项�?
PDFBox http://sourceforge.net/projects/pdfbox/ (处理PDF文档的项�?
Lucene http://jakarta.apache.org/lucene/index.html (搜烦引擎)
Digester http://jakarta.apache.org/commons/digester/ (处理XML信息的项�?
DBCP http://jakarta.apache.org/commons/dbcp/ (数据库连接池)
AXIS http://ws.apache.org/axis/ (WebService 的实现框�?
Jetspeed http://portals.apache.org/jetspeed-1/ (Portal)
HSQLDB http://sourceforge.net/projects/hsqldb/ (Im memory Database Engine)
CEWOLF http://sourceforge.net/projects/cewolf/(一套标�{�ֺ�实现Web报表,使用的是jFreeChart�?
Struts Menu http://sourceforge.net/projects/struts-menu/ (��Z��Struts的Web菜单��目)
htmlparser http://sourceforge.net/projects/htmlparser/ (用于解析HTML信息的项�?
Mondrian http://sourceforge.net/projects/mondrian/ (Open Source OLAPdatabase)
ProGuard http://sourceforge.net/projects/proguard/ (Java的�؜淆器)
InfoGlue http://sourceforge.net/projects/infoglue/ (J2EE 内容��理�pȝ��)
JPivot http://sourceforge.net/projects/jpivot/ (��Z��WEB的OLAP 展现)
HttpClient http://jakarta.apache.org/commons/httpclient/ 处理http客户端的接口

草儿 2007-08-25 23:16 发表评论

JavaFX�~�程语言基础

草儿 — Thu, 16 Aug 2007 16:39:00 GMT
     摘要: JavaFX Script™ �Q�下文中成�ؓJavaFX�Q�语�a�是一�U�声明式的静态类型编�E�语�a�。它��h��W�一�U�函敎ͼ�first-class functions�Q�、声明式的语法、列表推��|��list-comprehensions�Q�及��Z��依赖关系的增量式求��|��incremental dependency-based evaluation�Q�等特征。JavaFX 脚本式语�a�特别适用于Java2D ...  阅读全文

草儿 2007-08-17 00:39 发表评论

草儿 — Thu, 16 Aug 2007 16:36:00 GMT
     摘要: Translated by Liu Dan (cleverpig) and Tian Le (Tin) 本文档将讨论在JavaFX语言中可用的各种GUI�l��g�Q��ƈ提供�C�Z��代码�Q�讨论JavaFX�l��g与Swing GUI�l��g相比的差异�? 前提条�g 如果你从前没有阅读过JavaFX脚本语言��h��教程�Q�那么我们强烈推荐你在��l�阅��L��文档之前首先阅读JavaFX脚本语言��h��教程�?你应该具有熟...  阅读全文

草儿 2007-08-17 00:36 发表评论

讉K��内存中JDBC驱动信息的小�E�序

草儿 — Mon, 13 Aug 2007 03:43:00 GMT

在你同内存中多个JDBC驱动打交道的�q�程中，你可以访问更多的有关JDBC驱动的信息。下面是是访问这些内容的参考代码：
import java.sql.*; import java.util.*; public class drvinf{ public static void main(String[] args) {    //�l�定属性文�?br> ResourceBundle bundle = ResourceBundle.getBundle("START"); Connection conn=null; String drv=null; String url=null; //加蝲JDBC 驱动 try{      drv = bundle.getString("Driver");      Class.forName(drv);      }catch (ClassNotFoundException e)        {System.out.println(e.getMessage());} //JDBC URL=jdbc:odbc:bank try{      url = bundle.getString("jdbcURL");      conn = DriverManager.getConnection(url);      List drvs = Collections.list(DriverManager.getDrivers());      for (int i=0; i       {        System.out.println("----------------打印有关驱动的信�?-----------");        Driver driver = (Driver)drvs.get(i);        String name = driver.getClass().getName();        System.out.println(name);        int maxV = driver.getMajorVersion();        System.out.println(maxV);        int minV = driver.getMinorVersion();        System.out.println(minV);        boolean comp = driver.jdbcCompliant();        System.out.println(comp);        }        }catch (SQLException e)     {System.out.println(e.getMessage());}        try{           if(conn!=null)conn.close();           }catch(SQLException e)                   {System.out.println(e.getMessage());}     } }START.properties 中的内容�Q?
Driver=sun.jdbc.odbc.JdbcOdbcDriver jdbcURL=jdbc:odbc:bank login=admin password=hashflush

草儿 2007-08-13 11:43 发表评论

草儿 — Thu, 09 Aug 2007 06:59:00 GMT

Java.awt.Robot �cȝ��于控刉��标和键盘。一旦你得到�q�种控制�Q�你能够通过你的Java代码做与
鼠标和键盘�Q何类型的操作.�q�个�c�通常用于自动化测试。先面的代码样例��向您展�C�Robot
�c�d��何处理键盘事件。如果你�q�行此代码，�q�打开notepad�Q�您��在notepad中看到HI CAOER。赶快试一试吧�?br>import java.awt.AWTException;
import java.awt.Robot;
import java.awt.event.KeyEvent;

public class RobotExp {

public static void main(String[] args) {

try {

Robot robot = new Robot();
//定义5�U�的延迟以便你打开notepad 哈哈
// Robot 开始写
robot.delay(5000);
robot.keyPress(KeyEvent.VK_H);
robot.keyPress(KeyEvent.VK_I);
robot.keyPress(KeyEvent.VK_SPACE);
robot.keyPress(KeyEvent.VK_C);
robot.keyPress(KeyEvent.VK_A);
robot.keyPress(KeyEvent.VK_O);
robot.keyPress(KeyEvent.VK_E);
robot.keyPress(KeyEvent.VK_R);

} catch (AWTException e) {
e.printStackTrace();
}
}
}

草儿 2007-08-09 14:59 发表评论

草儿 — Thu, 09 Aug 2007 05:36:00 GMT
     摘要: 原作者： Anghel Leonard旉��Q?8/01/2007��译�Q�Caoer2007�q?�?�?JavaFX 代码同Java代码极容易集�? �q�有一个��用JavaFX装蝲一个图片到�H�体例子�Q�它允许使用者选择一个矩形区域保存这个矩形区域。这个捕捉保存操作由Java代码完成�?源码列表 15 import java.io.*; import javafx.ui.*; import jav...  阅读全文

草儿 2007-08-09 13:36 发表评论

JavaFX入门教程一

草儿 — Tue, 07 Aug 2007 03:49:00 GMT

原作者： Anghel Leonard
旉��Q?/span>08/01/2007
��译�Q?/span>Caoer
2007�q?/span>8�?/span>5�?/span>

什么是JavaFX�Q?/span>SUN�Q�太阛_��司）�?/span>2007�q�春天发布了一个叫JavaFX新框架。这是一个泛泛的名字�Q�因�?/span>JavaFX主要包含Script and Mobile两个�l��g�Q�在��来SUN��开发更多的�l��g�?/span>

JavaFX 的核心是 JavaFX 脚本�Q�是一个声明式脚本语言。尽��同Java代码非常不同�Q�但是同Java�c�d��有很高的交互度�?/span> JavaFX 中的很多�c�M��要�ؓ了更�Ҏ��实现Swing�?/span>Java2D而设计的。��?/span> JavaFX 脚本�Q�您能很�Ҏ��的�ؓ文本和图形开�?/span>GUI接口、动��d��非常COOL的效果。�ƈ且，您能��?/span>Java�?/span>HTML代码包装�?/span> JavaFX 脚本中�?/span>

�W�二个组�?/span>- JavaFX Mobile�Q�是为移动设备开�?/span>Java应用的��^台。它最�l�会成�ؓ开�?/span> JavaFX 脚本的��^��C��是现在同�q�篇文章实用的技术还很不兼容�?/span>

JavaFX 应用的一些例�?/span>

在开始学习一门新的语�a�前，让我们先看一�?/span>JavaFX代码的一些例子�?/span>JavaFX 官方站点��h��大量�?/span>JavaFX 实例。请点击JavaFX Script 2D Graphics Tutorial下蝲该实�?/span>. 下蝲完成以后�Q�双�?/span>tutorial.jnlp 文�g卛_��q�行。几�U�过后，你应该能够看到如图一�?/span>JavaFX实例�q�行场景�Q�若没有出现该图片，你必��Mؓ.jnlp扩展名重新配�|?/span>Java Web Start�Q��?/span>

图一、运�?/span> tutorial.jnlp tutorial

�׃��旉��看一看这些例子和源代码。仅仅��用有限的几行JavaFX代码��p��得到很多有趣的效果。如果你对于JavaFX的应用还是感到摸不着头脑�Q�看一看下面的两个demo。它们是StudioMoto �?/span> Tesla Motors 站点的部分重新实现。您可以�?/span>OpenJFX ��目站点下蝲OpenJFX 脚本Studiomoto Demo �?/span> Tesla Demo。它们需�?/span>Java Web Start 才能�q�行�Q�但是也取决于你的机器配�|�它们可能自动运行，或者你必须扑ֈ�和运行已�l�下载的.jnlp文�g�?/span>

下蝲安装JavaFX

如果你对于学习开�?/span>JavaFX应用�E�序�Q�您应该了解臛_��使用JavaFX三个�Ҏ��。同时了�?/span>JavaFX应用�E�序不是��Z��览器的也很重要。最��单最快捷的方法是��Z��?/span>JavaFXPad轻量�U�的工具。��用该工具的主要优势是你总能立即看到你在�~�辑器里所作更改的效果。你能从JavaFX��目�|�站下蝲到该工具�Q?/span> JavaFXPad �Q�。�ƈ且运行它需�?/span>Java Web Start �Q�如图二�Q��?/span>

图二、运�?/span>JavaFXPad�~�辑�?/span>

使用JavaFX的另一�U�方式是使用JavaFX脚本NetBeans 5.5插�g或�?/span>Eclipse 3.2插�g�Q�需要下载和安装NetBeans 5.5 或�?/span> Eclipse 3.2.2以上集成开发工�?/span> �Q�。若您已�l��?/span> NetBeans 5.5开始你�?/span>JavaFX之旅,OpenJFX��目�|�站的对�?/span>NetBean开�?/span>JavaFX的说�?/span>��会�l�予你帮助�?/span> �怼�的如果您使用��Z��Eclipse�?/span>JavaFX插�g�Q�您可以�?/span>JavaFX�?/span>Eclipse插�g。注意这��文章中的所有例子已�l�在NetBeans5.5�?/span>JavaFX插�g中测试过�Q�但是应该能够��用其他方法运行�?/span>

使用NetBeans 5.5下的JavaFX插�g开�?/span>Hello World �E�序

每当开始学习一门新的语�a��Ӟ��我们必定要写Hello World ��程序：

源码列表1

import javafx.ui.*;

import java.lang.System;

Frame {

centerOnScreen: true

visible: true

height: 50

width: 350

title: "HelloWorld application..."

background: yellow

onClose: operation() {System.exit(0);}

content: Label {

text: "Hello World"

}

}

�?/span>NetBeans5.5开发和�q�行�q�个��程序步骤如�?/span>:

1.                   启动NetBeans 5.5.

2.                   从主菜单选择File -> New Project.

3.                   在新��目�H�口,选择目录常规目录�?/span> Java 应用��目(点击下一�?/span>).

4.                   在新�?/span>Java应用�E�序�H�口,在项目名文本框敲�?/span> "FXExample".

5.                   在相同窗口，用浏览按钮选择��目的目�?/span>.

6.                   取消 "Set as main project" �?/span> "Create main class" 复选框 (点击完成).

7.                   叛_��FXExample -> Source Packages 和选择 New -> File/Folder.

8.                   在新的文件窗口，选择另一个目录和JavaFX文�g�c�d��Q�点��M��一步）.

9.                   在新�?/span>JavaFX文�g�H�口�Q�敲�?/span>"HelloWorld" 作�ؓ文�g名和"src"作�ؓ目录(点击完成).

10.               拯��源码列表1�?/span> HelloWorld.fx.

11.               叛_��FXExample ��目选择��目属�?/span>.

12.               在项�?/span>FXExample属性对话框 ,选择从目录面板运行节�?/span>.

13.               在参数文本框敲入 "Hello World" (点击完成).

14.               叛_��FXExample ��目选择�q�行��目选项.

如果一切良�?/span>,你应该看��C��个窗体如图三�Q?/span>

图三�?/span> �?/span>NetBeans 5.5中运�?/span> Hello World 应用�E�序

现在你拥有了开发和�q�行��M��JavaFX应用�E�序�?/span>IDE软�g支持.

JavaFX 语法

在正式开始学�?/span>JavaFX�Q�让我们��览一遍该语言的语法要炏V��如果你非常熟悉Java语言�Q�这些语法的大多��C��让你感到非常熟悉�Q�但是有一些会相当不一栗��?/span>

JavaFX 原始�c�d��

JavaFX 支持原始�c�d��Q?/span>String (对应�?/span> java.lang.String), Boolean (对应�?/span> java.lang.Boolean), Number (对应�?/span> java.lang.Number) �?/span> Integer (对应�?/span> byte,short,int,long,BigInteger).

JavaFX 变量

一�?/span>JavaFX变量使用var关键字声明。看下面的例子：

var x:Number = 0.9;

var name:String = "John";

var y:Integer = 0;

var flag:Boolean = true;

var numbers:Number = [1,2,3,4,5]�Q?/span>

JavaFX 操作�W?/span>

众所周知�?/span>Java操作�W?/span>&&, || �?/span> ! �?/span>JavaFX中采用下面的形式�Q?/span>

·                     Java: &&
JavaFX: and

·                     Java: ||
JavaFX: or

·                     Java: !
JavaFX: not

JavaFX �Ҏ��

JavaFX 支持�q�些�Ҏ��. ��h��参数、变量声明和�q�回值的�Ҏ��举例�Q?/span>

function taxes(x) { var t:Number = (19.0/100.0)*x; return t; }

JavaFX if 语句

�?/span>JavaFX中，你你能通过使用if语句使用条�g判断�?/span>

if (条�g) { //动作 } else if (条�g) { //动作 } else { //动作 }

JavaFX while 语句

�q�个 while 语句同在Java中的while语句�怼��?/span> while (条�g) { //动作}

JavaFX for 语句

for 语句用于循环和间隔（间隔使用�Ҏ��?/span>[]�?/span> .. �W�号表示).

//i ��取��|�� 0, 1, 2, 3, 4, 5象在 (i in [0..5]) { //伴随 i的动�?/span> }代码块中

JavaFX �q�程

JavaFX �q�程�?/span>operation 关键字�ؓ标志。一个简单的例子�Q?/span>

operation startClock() {do{ while(true) {

if(seconds>=360) {seconds = 0; seconds = [0,6..360] dur 60000 linear;}

if(minutes>=360) {minutes = 0; minutes = [0,6..360] dur 3600000 linear;}

if(hours>=360) {hours = 0; hours = [0,6..360] dur 43200000 linear;} } }}

JavaFX �c?/span>

JavaFX �c�M��?/span>class关键�?/span>. 一�?/span> JavaFX �c�能够��?/span>extends 关键字��承多个类使用逗号分割
�q�些�cȝ��名字。在花括号中间你可以攑ֱ�性、方法和�q�程�Q�例如下面的例子�Q?/span>

class Order {

attribute order_nr: String;

attribute ordertype: Order inverse Order.products;

attribute products: Order* inverse Order.ordertype;

function getOrderNr(): String;

operation addOrder(order: Order);

}

注意属性��?/span>attribute关键字声明，�Ҏ��体和�q�程不在�c�M��中，它们单元定义在类声明以后�Q�在下文你很快就能看到�?/span> inverse 子句是一个可选项 �Q�它表示一�U�同在类中另一个属性的双向关系。在�q�个案例�?/span>JavaFX��自动完成更斎ͼ�插入、替代和删除�Q�你能在Java.net上找到更完整�?/span>文档�?/span>

熟悉JavaFX

在本��节�Q�您��会看到一�p�d��的小例子�Q�这些例子覆�?/span>JavaFX的各�U�特性和功能。主要目的是让你熟悉JavaFX代码�?/span>JavaFX应用�E�序的逻辑。第二个目标是当你需要开发仅仅需要几行代码就会有非常��L��GUI�Q�动��d��好的效果时候��你确�?/span>JavaFX值得好好研究一下。所有列出的例子��介�l�关�?/span>JavaFX的技巧。每一个例子只使用很少的描�q�处理，所以不要想扑ֈ�大量的注释。所有这些可讉K��的例子你都是你自己就能运行的�Q�所以让我们开始吧。当我们需要��?/span>System.out.println 打印属性值时候，你可以把它的名字放进含有引用的字�W�串�Q�象源码列表2中所�C�的那样�?/span>

源码列表2

//带有应用文本的表辑ּ�

import java.lang.System;
var mynumber:Number = 10;
System.out.println("数字�?/span>: {mynumber}");

�l�果: 数字�?/span>: 10
JavaFX 支持变量的计数这样一个有用的功能。这个功能利用下面的三个操作�W�实玎ͼ�

·                     ?: 可选的(可能�?/span> null)

·                     +: 1或多�?/span>

·                     *: 0或多�?/span>

源码列表3

//变量计数

import java.lang.System;
var mynumbers:Number* = [1,2,7];
System.out.println("数字�?/span>: {mynumbers}");

�l�果: 数字�?/span>: 1 2 7
�?/span>JavaFX�?/span>, 在声明部分不指定变量的类型是可能的�?/span> �q�不会��生错误，因�ؓJavaFX ��在该变量的使用中自动发现它的类型�?/span>

源码列表 4

//变量�c�d��是可选的

import java.lang.System;
var days = ["Monday,","Friday,","Sunday"];
System.out.println("你必��d��?/span>: {days}");

�l�果: 你必��d��?/span>: Monday, Friday, Sunday
你可以��?/span>sizeof 操作�W�得��C��个数�l�的大小�Q?/span>

源码列表 5

//得到一个数�l�的大小

import java.lang.System;
var lotto = [21,30,11,40,5,6];
System.out.println("数组大小:{sizeof lotto}");

�l�果: 数组大小: 6

您能使用 [] 操作�W�得到满��x��定条件的子数�l�。条件放�?/span> [] 中作为布��判�?/span> 。这个与XPath 谓词�怼�.

源码列表 6

//使用[] 操作�W?/span> -�?/span> XPath�怼�

import java.lang.System;
var mynumbers = [1,2,7,3,30,15,14,6,4];
var numbers = mynumbers[n|n < 10];
System.out.println("��于10的数字�ؓ: {numbers}");

�l�果: ��于10的数字�ؓ: 1 2 7 3 6 4
你可以��?/span>indexof 操作�W�得到指定序��C��|�的数组中一个元�?em>�Q?/em>

源码列表 7

//�q�回指定序数位置的数�l�中的元�?/span>

import java.lang.System;

var mynumbers = [1,2,7,3,30,15,14,6,4];
var number_four = mynumbers[indexof . == 4];
System.out.println("数字4:{number_four}");

�l�果: 数字4: 30

当您惌��向一个数�l�中插入一个元素时�Q�你可以使用下列 insert 语句中的一�?/span>:

·                     as first: 在第一个位�|�插�?/span>

·                     as last:在最后一个位�|?/span>(默认)插入

·                     before: 在前一个位�|�插�?/span>

·                     after:在下一个位�|�插�?/span>

你可以��?/span> delete 语句从一个数�l�中删除一个元�?/span>.

源码列表8

//插入和删除语�?/span>
import java.lang.System;
var mynumbers = [1,2,7];
System.out.println("Before inserting anything: {mynumbers}");
insert 10 into mynumbers;
System.out.println("After inserting at the end the \"10\" value:{mynumbers}");
insert [8,6,90] as first into mynumbers;
System.out.println("After inserting at the first positions the \"8,6,90\" values:{mynumbers}");
insert 122 as last into mynumbers;
System.out.println("After inserting at the end the \"122\" value:{mynumbers}");
insert 78 before mynumbers[3];
insert 11 after mynumbers[3];
System.out.println("After inserting the \"78\" and \"11\" values before/after the 3rd element:{mynumbers}");
delete mynumbers[. == 122];
System.out.println("After deleting:{mynumbers}");

�l�果:
Before inserting anything: 1 2 7
After inserting the 10 value at the end: 1 2 7 10
After inserting the 8, 6, and 90 values at the first positions: 8 6 90 1 2 7 10
After inserting the 122 value at the end: 8 6 90 1 2 7 10 122
After inserting the 78 and 11 values before/after the 3rd element: 8 6 90 78 11 1 2 7 10 122
After deleting: 8 6 90 78 11 1 2 7 10

JavaFX中的一个非常好的功能是list。这个功能��?/span> select �?/span> foreach 操作�W�实现。这有两个例子（一个��?/span> select 和��?/span> foreach) 得到指定间隔的奇数�?/span>

源码列表9

//JavaFX中的 select �?/span> foreach 操作�W?/span>

import java.lang.System;
function odd(p:Number)
{ return select i from i in [1.0 ..p]
where (i%2 == 0.0);
}

var result = odd(10.0);
System.out.println("Odd numbers:{result}");

�l�果: Odd numbers: 2.0 4.0 6.0 8.0 10.0

源码列表10 (�?/span> 源码列表 9相同, 但是�?/span> foreach)

//JavaFX中的select �?/span> foreach 操作�W?/span>

import java.lang.System;
function odd(p:Number) {
       return foreach (i in [1.0 ..p]
     where (i%2 == 0.0)) i;
     }
var result = odd(10.0);
System.out.println("Odd numbers:{result}");

�q�个例子昄��?/span> foreach 对于创徏好的效果非常有用�?/span>

源码列表11

//JavaFX中的 select �?/span> foreach 操作�W?/span>

import java.lang.*;
import javafx.ui.*;
import javafx.ui.canvas.*;
Frame {
centerOnScreen: true
visible: true
height: 500
width: 500
title: "Foreach demo..."
onClose: operation() {
System.exit(0);
}
content: ScrollPane {
background: white
view: Canvas {
content: bind
foreach (i in [1..8], j in [1..8])
Rect { x: i*30 y: j*30 width:30 height:30 fill: Color {red: (100+i) green: (100+j) blue: (100+(i*j))
}
stroke:white
strokeWidth:1 } }

}

}

囑֛�. �q�行源码列表 11

使用双箭头括号引用�ؓJavaFX关键字的变量名或者属性名�Q�如下所�C��?/span>

源码列表 12

//标志�W�引�?/span>

import java.lang.System;

for (<> in [0..3]) {

System.out.println("for = {<>}");

}

�l�果: for = 0 for = 1 for = 2 for = 3

当你需要开�?/span>Swing接口�Ӟ��JavaFX 是一个伟大的工具�Q�因�?/span> JavaFX 考虑了非常多用来降低代码量和�?/span>javax.swing.*�?/span>�q�存友好。在上一节（使用NetBeans5.5中的JavaFX插�g��试Hello World应用�E�序�Q�，你看��C��创徏一个窗体是如何�Ҏ��。这有两个更好的例子�Q�创建按钮和文本框�?/span>

源码列表 13

import javafx.ui.*;

import java.lang.System;

Frame{

content: Button { text: "Exit" action: operation() { System.exit(0); } }

visible: true

}

图五. �q�行源码 13

源码列表14

import javafx.ui.*;

Frame {

content: GroupPanel { var myRow = Row { alignment: BASELINE }

var label_col = Column { alignment: TRAILING }

var field_col = Column { alignment: LEADING }

rows: [myRow] columns: [label_col, field_col]

content: [SimpleLabel { row: myRow column: label_col text: "Type your text here:" }, TextField { row: myRow column: field_col columns: 50 }] }

visible: true

};

囑օ�. �q�行源码 14

Java.net 也有使用JavaFx创徏 Swing接口的教�E��?/span>

草儿 2007-08-07 11:49 发表评论

��Z��Struts1.2.9框架的登录页面的处理�q�程

草儿 — Fri, 03 Aug 2007 03:36:00 GMT

Struts Web框架是现在构建Web应用必须的开发框架之一。以下是我们学习Struts框架旉��常都会看到的登录页面程序的处理��程分析�Q�希望和�q�大博友交流�Q?/p>

��Z��Struts框架��d��E�序应用的UML��序�?br>

处理步骤�Q?/p>
1、客户从��览器客��L��向Web服务器发��求，服务器将��h��转发到Web容器�Q�比如：Tomcat�Q�根据请求�\径URL扑ֈ�ActionServlet�Q�Web容器调用Servlet的servic()�Ҏ��Q�根据请求参数的不同调用doGet()或者doPost()�Ҏ��?/p>
2、而ActionServlet的doGet()或者doPost()�Ҏ��调用process()�Ҏ��处理��h��和响应，生成RequestProcess对象处理配置文�gstruts-config.xml中的配置信息�Q�依�ơ调用processMapping()-查找处理此次��h��的Action信息�q�返回ActionMapping对象�Q�processActionForm()--创徏此次��h��的ActionForm对象�Q�processActionCreate()--创徏处理此次��h��的Action实例�Q�LoginAction对象�Q�；processActionPerform()--执行Action实例的execute()�Ҏ��?/p>
3、通过调用execute()�Ҏ��获取LoginForm存储的用户和密码�{�数据信息，其中��ActionForm Bean、ActionMapping、request、response对象传递给LoginAction对象�Q�Action实例�Q�；执行完必要的逻辑处理比如查询数据库后�Q�返回一个ActionForward对象�Q�由该对象调用RequestProcess对象中的processForwardConfig()�Ҏ��解析配置文�g中蟩转参敎ͼ�转发到相应的View��面success.jsp或者failure.jsp�?/p>

草儿 2007-08-03 11:36 发表评论

JSP在TOMCAT中的处理生命周期

草儿 — Sat, 14 Jul 2007 06:43:00 GMT

1、将WEB应用部��v到TOMCAT容器�Q�容器启动读取应用的部��v文�gweb.xml,但不�?jsp文�g做�Q何处理请求�?/div>
2、客��L��击连接请求某�?jsp文�g�Q�容器开始将.jsp文�g转换��Z��个servrlet�cȝ��.java源代码。查看指令，得到转换的可能需要的信息。创��Z��个HttpServlet子类�Q�对于Tomcat5所生成的servlet会扩展org.apache.jasper.runtime.HttpJspBase�c�R��若有一个page指��o有import属性，生成的类文�g的最上面会写入import语句。例如在Tomcat5中加入包语句�Q�package org.apache.jsp�Q�若有声明容器将�q�些声明写道�c�L��Ӟ��通常攑֜�服务�Ҏ��的下面。Tomca5声明了自��q��一个静态方法和一个实例方法。然后徏立服务方法，�Ҏ��名�ؓ_jspService()。所生成的servlet会覆盖servlet��类的service()�Ҏ��。_jspService()直接由service()调用�Q�要接收HttpServletRequest和HttpServletResponse参数。在建立�q�个�Ҏ��的时候，容器会声明�ƈ初始化所有的隐式对象。将普通的HTML�Q�模板文�Ӟ��、scrptlet和表辑ּ�攑ֈ�服务�Ҏ��里，�q�行格式化，�q�写至PrintWrite响应输出�?/div>
3、容器尝试将�q�个servlet.java源文件编译�ؓ.class文�g�?/div>
4、容器家在新生成的servlet�c�R�?/div>
5、容器实例化servlet�Q��ƈ��D��servlet的jspInit()�Ҏ��q�行。对象现在已成�ؓ一个完整的servlet准备��q�A�Q�接受客��L��h��?/div>
6、容器创��Z��个新�U�程来处理客戯��求，servlet的service()�Ҏ��q�行。以后的处理同普通的servlet处理�q�程。最�l�servlet向客戯��回一个响应�?/div>
需要注意的是：在JSP生命周期中，JSP的�{换和�~�译�q�程只发生一�ơ。一旦第一�ơ编译完成，以后的调用同普通的servlet一栗��大多数容器开发商提供预�{化和�~�译的办法，是这些工作提前完成�?/div>

草儿 2007-07-14 14:43 发表评论

一个Servlet生命周期�Q�Tomcat处理��h��中）

草儿 — Sat, 07 Jul 2007 08:04:00 GMT
从Tomcat处理用户��h��Q�我们可以清晰的看到容器Servlet的生命周期管理过�E�：
1、客户发��求�?gt;Web 服务器�{发到Web容器Tomcat�Q?br>2、Tomcat�ȝ��E�对转发来用��L��h��做出响应创徏两个对象�Q�HttpServletRequest和HttpServletResponse�Q?br>3、从��h��中的URL中找到正��Servlet�Q�Tomcat为其创徏或者分配一个线�E�，同时�?创徏的两个对象传递给该线�E�；
4、Tomcat调用Servlet的servic()�Ҏ��Q�根据请求参数的不同调用doGet()或者doPost()�Ҏ��Q?br>5、假设是HTTP GET��h��Q�doGet()�Ҏ��生成静态页面，�q�组合到响应对象里；
6、Servlet�U�程�l�束�Q�Tomcat��响应对象�{换�ؓHTTP响应发回�l�客��P��同时删除��h��和响应对象�?br>从该�q�程中，我们可以理解Servlet的生命周期：Servlet�c�d��载（对应3步）�Q�Servlet实例化（对应3步）�Q�调用init�Ҏ��Q�对�?步）�Q�调用service()�Ҏ��Q�对�?�?步）�Q�；调用destroy()�Ҏ��Q�对�?步）�?img src ="http://www.aygfsteel.com/mlh123caoer/aggbug/128789.html" width = "1" height = "1" />

草儿 2007-07-07 16:04 发表评论

Adobe Flex2

草儿 — Fri, 06 Jul 2007 02:59:00 GMT

Flex2应用�E�序在无所不在的轻量��虚拟机Flash播放�?跨��^台运行。该�q�_��包括以下技术：
1、一�U�基于XML的MXML语言�Q�它支持面对设计者的GUI�l��g声明式编�E�；
2、标准的OOP语言�Q�基于最新的ECMASript规范的AS3�Q?br>3、��用FDS�Q�Flex Data Services�Q�方式进行服务端集成�Q�是客户端程序能够对J2EE世界透明讉K��Q?br>4、图表组�Ӟ��
5、基于Eclipse功能强大的IDE�Q�拥有自动化部��v�Q�调试，代码跟踪能力�?br>Flex2�q�_��易于扩展也对服务端技术例如JAVA�Q�ColdFusion�Q�PHP�Q�Ruby�Q�ASP�{�等实现集成。即��发布的Adobe Apollo版允许基于Flash Player�Q�Flex�Q�PDF和HTML桌面�E�序的构建�?br>SWF文�g格式是开攄��Q�有�W�三方开源��品象Laszlo�pȝ��的OpenLaszlo为构建RIA�E�序提供工具�Q�程序��用Flash Player发布�?br>与上一个版本相反，Flex2提供一�U�不会招致授权协议纠�U��构建RIA的方式。以下都免费得到�Q?br>1、MXML�Q�基于XML声明式用来构建GUI的编�E�语�a��Q?br>2、ActionScript3.0�Q�与JAVA�怼�的OOP语言�Q?br>3、Flash Player9�Q�运行在WEB��览器占有很��内存的虚拟机，�q�行你编译的二进制代码（.SWF�Q?
4、命令行�~�译器和调试器；
5、Flex 框架�Q�包含设计良好的GUI�l��g库：按钮�Q�tab目录�Q�数据网��|��树控�Ӟ��动画效果�{�等很多�?br>6、Flex数据服务预览版：部��v在J2EE服务器WEB�E�序与运行在Flash Player上的ActionScript客户端程序通信模板。FDS预览版只能运行在单CPU上�ƈ且不支持在（24*7�Q�高可访问性配�|�模式下使用�?/p>
构徏一个基本的Flex2�E�序步骤有：
1、通过增加XML�l��g例如下面按钮来构��个程序：

若��用收费的开发工具Flex Builder IDE�Q�你��可以��用拖拉技术了。当�Ӟ��你也可以手写MXML文本�?br>2、写按照业务逻辑ActionScript代码�Q�例如：
private function processOrder (event:Event):void{
//业务逻辑代码
}
3、编译代码。Flex�~�译器自动的把MXML转换为ActionScript代码�q�以SWF格式字节码输出在Flash Player 9或者更高版本运行，如果你用Flex Builder IDE�Q�你��得到更爽的自动化编译过�E��?br>4、在你选择的WEB服务器中部��vSWF文�g和封装好的HTML��面。如果你用收��q��那个工具�Q�这些过�E�完全透明�?br>有一个在�U�Flex�~�译器网站，你可以试着写一些Flex代码而不用在你自��q��电脑上安装�Q何东�ѝ��同时该�|�站提供了一些示例代码供您修改和�q�行。还�{�什么，GO�Q?a >http://try.flex.org/

草儿 2007-07-06 10:59 发表评论

草儿 — Mon, 25 Jun 2007 10:33:00 GMT
JDOM是一�U��?XML 的独�?Java 工具包，用于快速开�?XML 应用�E�序。它�?/font>设计�?/font>�?Java 语言的语法乃臌��义�?
      JDOM是两位著名的 Java 开发�h员兼作者，Brett Mclaughlin �?Jason Hunter 的创作成果， 2000 �q�初�?/font>�c?/u>��g�� Apache 协议的许可下�Q�JDOM 作�ؓ一个开放源代码��目正式开始研发，JDOM 作�ؓ一个开放源代码��目正式开始了。它已成长�ؓ包含来自�q�泛�?Java 开发�h员的投稿、集中反馈及错误修复的系�l�，�q�致力于建立一个完整的��Z�� Java �q�_��的解��x��案，通过 Java 代码来访问、操作�ƈ输出 XML 数据�?

      虽然许多Java 开发�h员每天都在��?XML�Q�Sun 却在��?XML 整合�q?Java �q�_��斚w��落后了。因为在 XML 成�ؓ从商家对商家集成�?Web 站点内容��水化等斚w��的关键技术之前，Java 2 �q�_��已�l�非常流行了。Sun 已经使用 JSR �q�程使之成�ؓ现存 XML API 的��E��，�q�一点已被广泛接受。目前最显著的是加入�?JAXP �Q�用�?XML 语法分析�?Java API�Q�，其中包含了三�?a target=_new>软�g�?/font>�Q?

      ·org.w3c.dom �Q�W3C 推荐的用�?XML 标准规划文档对象模型�?Java 工具
      ·org.xml.sax �Q�用于对 XML �q�行语法分析的事仉��动的��?API
      ·javax.xml.parsers �Q�工厂化工具�Q�允许应用程序开发�h员获得�ƈ配置�Ҏ��的语法分析器工具 JDOM 能够替换 org.w3c.dom 软�g包来有计划地操作 XML 文档

      JDOM是一�?a target=_new>开�?/font>��目�Q�它��Z��树型�l�构�Q�利用纯JAVA的技术对XML文档实现解析、生成、序列化以及多种操作�?/p>
      JDOM 直接为JAVA�~�程服务。它利用更�ؓ强有力的JAVA语言的诸多特性（�Ҏ��重蝲、集合概念以及映��）�Q�把SAX和DOM的功能有效地�l�合��h��?/p>
      Jdom是用Java语言诅R��写、操作XML的新API函数。Jason Hunter �?Brett McLaughlin公开发布了它�?.0版本。在直觉、简单和高效的前提下�Q�这些API函数被最大限度的优化。在接下来的��幅里将介绍怎么用Jdom去读写一个已�l�存在的XML文档�?/p>

      在��用设计上��可能地隐藏原来使用XML�q�程中的复杂性。利用JDOM处理XML文档��是一件轻松、简单的事�?/p>
      JDOM �?000�q�的春天被Brett McLaughlin和Jason Hunter开发出来，以��I补DOM及SAX在实际应用当中的不��之处�?/p>
      �q�些不��之处主要在于SAX没有文档修改、随��问以及输出的功能�Q�而对于DOM来说�Q�JAVA�E�序员在使用时来用�v来总觉得不太方�ѝ�?/p>
      DOM的缺点主要是来自于由于Dom是一个接口定义语�a��Q�IDL�Q?它的��d��是在不同语言实现中的一个最低的通用标准�Q��ƈ不是为JAVA特别设计的。JDOM的最新版本�ؓJDOM Beta 9。最�q�JDOM被收录到JSR-102内，�q�标志着JDOM成�ؓ了JAVA�q�_��l�成的一部分�?/p>
      �?JDOM 中，XML 元素��是 Element 的实例，XML 属性就�?Attribute 的实例，XML 文档本��n��是 Document 的实例�?/p>
      因�ؓ JDOM 对象��是�?Document、Element �?Attribute �q�些�cȝ��直接实例�Q�因此创��Z��个新 JDOM 对象��如�?Java 语言中��?new 操作�W�一样容易。JDOM 的��用是直截了当的�?/p>
      JDOM 使用标准�?Java �~�码模式。只要有可能�Q�它使用 Java new 操作�W�而不故弄玄虚使用复杂的工厂化模式�Q��对象操作即便对于初学用户也很方便�?/p>

一、JDOM包概�?/strong>

JDOM是由以下几个包组成的

org.jdom包含了所有的xml文档要素的java�c?br>org.jdom.adapters包含了与dom适配的java�c?br>org.jdom.filter包含了xml文档的过滤器�c?br>org.jdom.input包含了读取xml文档的类
org.jdom.output包含了写入xml文档的类
org.jdom.transform包含了将jdomxml文档接口转换为其他xml文档接口
org.jdom.xpath包含了对xml文档xpath操作的类

二、JDOM�c�说�?/strong>

      1、org.JDOM�q�个包里的类是你J解析xml文�g后所要用到的所有数�?a target=_new>�c�d��?/p>
Attribute
CDATA
Coment
DocType
Document
Element
EntityRef
Namespace
ProscessingInstruction
Text

      2、org.JDOM.transform在涉及xslt格式转换时应使用下面�?个类

JDOMSource
JDOMResult
org.JDOM.input

      3、输入类�Q�一般用于文档的创徏工作

SAXBuilder
DOMBuilder
ResultSetBuilder

      4、org.JDOM.output输出�c�，用于文档转换输出

XMLOutputter
SAXOutputter
DomOutputter
JTreeOutputter

      使用前注意事��：

      1.JDOM对于JAXP以及TRax的支�?/p>
      JDOM支持JAXP1.1�Q�你可以在程序中使用��M��的parser工具�c?默认情况下是JAXP的parser�?br>制定特别的parser可用如下形式
SAXBuilderparser
=newSAXBuilder("org.apache.crimson.parser.XMLReaderImpl");
Documentdoc=parser.build("http://www.cafeconleche.org/");
//workwiththedocument...
JDOM也支持TRaX�Q�XSLT可通过JDOMSource以及JDOMResult�c�L��转换�Q�参见以后章节）

      2.注意在JDOM里文档（Document�Q�类由org.JDOM.Document来表�C�。这要与org.w3c.dom中的Document区别开�Q�这2�U�格式如何�{换在后面会说明�?br>      以下如无�Ҏ��均指JDOM里的Document�?/p>
三、JDOM主要使用�Ҏ��

1.Ducument�c?/p>
(1)Document的操作方法：

Elementroot=newElement("GREETING");
Documentdoc=newDocument(root);
root.setText("HelloJDOM!");
或者简单的使用Documentdoc=newDocument(newElement("GREETING").setText("HelloJDOM!t"));
�q�点和DOM不同。Dom则需要更为复杂的代码�Q�如下：
DocumentBuilderFactoryfactory=DocumentBuilderFactory.newInstance();
DocumentBuilderbuilder=factory.newDocumentBuilder();
Documentdoc=builder.newDocument();
Elementroot=doc.createElement("root");
Texttext=doc.createText("Thisistheroot");
root.appendChild(text);
doc.appendChild(root);
注意事项�Q�JDOM不允许同一个节点同时被2个或多个文档相关联，要在�W?个文档中使用原来老文档中的节点的话。首先需要��用detach()把这个节点分开来�?/p>
(2)从文件、流、系�l�ID、URL得到Document对象�Q?/p>
DOMBuilderbuilder=newDOMBuilder();
Documentdoc=builder.build(newFile("jdom_test.xml"));
SAXBuilderbuilder=newSAXBuilder();
Documentdoc=builder.build(url);
在新版本中DOMBuilder已经Deprecated掉DOMBuilder.builder(url)�Q�用SAX效率会比较快�?br>�q�里举一个小例子�Q��ؓ了简单�v见，使用String对象直接作�ؓxml数据源：
PublicjdomTest(){
StringtextXml=null;
textXml="";
textXml=textXml+
"aaabbbcccddd";
textXml=textXml+"";
SAXBuilderbuilder=newSAXBuilder();
Documentdoc=null;
Readerin=newStringReader(textXml);
try{
doc=builder.build(in);
Elementroot=doc.getRootElement();
Listls=root.getChildren();//注意此处取出的是root节点下面的一层的Element集合
for(Iteratoriter=ls.iterator();iter.hasNext();){
Elementel=(Element)iter.next();
if(el.getName().equals("to")){
System.out.println(el.getText());
}
}
}
catch(IOExceptionex){
ex.printStackTrace();
}
catch(JDOMExceptionex){
ex.printStackTrace();
}
}
(3)DOM的document和JDOM的Document之间的相互�{换��用方法，��单！
DOMBuilderbuilder=newDOMBuilder();
org.jdom.DocumentjdomDocument=builder.build(domDocument);
DOMOutputterconverter=newDOMOutputter();//workwiththeJDOMdocument…
org.w3c.dom.DocumentdomDocument=converter.output(jdomDocument);
//workwiththeDOMdocument…

2.XML文档输出

XMLOutPutter�c�：
JDOM的输出非常灵�z?支持很多�U�io格式以及风格的输�?br>Documentdoc=newDocument(...);
XMLOutputteroutp=newXMLOutputter();
outp.output(doc,fileOutputStream);//Rawoutput
outp.setTextTrim(true);//Compressedoutput
outp.output(doc,socket.getOutputStream());
outp.setIndent("");//Prettyoutput
outp.setNewlines(true);
outp.output(doc,System.out);
详细请参阅最新的JDOMAPI手册

3.Element�c�：

(1)��览Element�?br>Elementroot=doc.getRootElement();//获得根元素element
ListallChildren=root.getChildren();//获得所有子元素的一个list
ListnamedChildren=root.getChildren("name");//获得指定名称子元素的list
Elementchild=root.getChild("name");//获得指定名称的第一个子元素
JDOM�l�了我们很多很灵�zȝ��使用�Ҏ��来管理子元素�Q�这里的List是java.util.List�Q?br>ListallChildren=root.getChildren();
allChildren.remove(3);//删除�W�四个子元素
allChildren.removeAll(root.getChildren("jack"));//删除�?#8220;jack”的子元素
root.removeChildren("jack");//便捷写法
allChildren.add(newElement("jane"));//加入
root.addContent(newElement("jane"));//便捷写法
allChildren.add(0,newElement("first"));

(2)�U�d��Elements:
在JDOM里很��?br>Elementmovable=newElement("movable");
parent1.addContent(movable);//place
parent1.removeContent(movable);//remove
parent2.addContent(movable);//add
在Dom�?br>Elementmovable=doc1.createElement("movable");
parent1.appendChild(movable);//place
parent1.removeChild(movable);//remove
parent2.appendChild(movable);//出错!
补充�Q�纠错�?br>JDOM的Element构造函敎ͼ�以及它的其他函数�Q�会��查element是否合法�?br>而它的add/remove�Ҏ��会检查树�l�构�Q�检查内容如下：
1.在�Q何树中是否有回环节点
2.是否只有一个根节点
3.是否有一致的命名�I�间�Q�Namespaces�Q?/p>
(3)Element的text内容��d��

Acooldemo

//Thetextisdirectlyavailable
//Returns"\nAcooldemo\n"
Stringdesc=element.getText();
//There'saconvenientshortcut
//Returns"Acooldemo"
Stringdesc=element.getTextTrim();
(4)Elment内容修改
element.setText("Anewdescription");
3.可正��解释特�D�字�W?br>element.setText("

四、JDOM的应�?/strong>

�Q�一�Q�、XML文档创徏

      我们由零开始利用JDOM生成一个XML文档。最后的�l�果(��h��文档)看�v来象�q�样�Q?/p>

kingwong

87654321

1.�?MyInfo 为根元素创徏文档

Element rootElement = new Element("MyInfo");//所有的XML元素都是 Element 的实例。根元素也不例外�Q�）
Document myDocument = new Document(rootElement);//以根元素作�ؓ参数创徏Document对象。一个Document只有一个根�Q�即root元素�?/p>
2.�l�根元素��d��属�?/p>
Attribute rootAttri = new Attribute("comment","introduce myself");//创徏名�ؓ commnet,��gؓ introduce myself 的属性�?br>rootElement.setAttribute(rootAttri);//��刚创徏的属性添加到根元素�?br>�q�两行代码你也可以合成一行来写，象这��P��
rootElement.setAttribute(new Attribute("comment","introduce myself"));
或�?br>rootElement.setAttribute("comment","introduce myself");

3.��d��元素和子元素

JDOM里子元素是作�?content�Q�内容）��d��到父元素里面�ȝ��,所谓content��是�c�M��上面��h��文档中之间的东东�Q�即kingwong。罗嗦了�Ҏ��吧：�Q?br>Element nameElement = new Element("name");//创徏 name 元素
nameElement.addContent("kingwong");//��kingwong作�ؓcontent��d��到name元素
rootElement.addContent(nameElement);//��name元素作�ؓcontent��d��到根元素

�q�三行你也可以合��Z��句，象这��P��
rootElement.addContent((Content)(new Element("name").addContent("kingwong")));//因�ؓaddContent(Content child)�Ҏ��q�回的是一个Parent接口�Q�而Element�c�d��时��承了Content�c�d��实现了Parent接口�Q�所以我们把它造型成Content�?/p>
我们用同��L��Ҏ��d��带属性的子元�?br>rootElement.addContent(new Element("sex").setAttribute("value","male"));//注意�q�里不需要�{型，因�ؓaddAttribute(String name,String value)�q�回值就是一�?Element�?/p>
同样的，我们��d��元素到根元素下，用法上一��P��只是�E�微复杂了一些：
rootElement.addContent((Content)(new Element("contact").addContent((Content)(new Element("telephone").addContent("87654321")))));
如果你对�q�种��写�Ş式还不太习惯�Q�你完全可以分步来做�Q�就象本节刚开始的时候一栗��事实上如果层次比较多，写成分步的�Ş式更清晰些，也不�Ҏ��出错�?/p>
4.删除子元�?/p>
�q�个操作比较��单：
rootElement.removeChild("sex");//该方法返回一个布��?/p>
到目前�ؓ止，我们学习了一下JDOM文档生成操作。上面徏立了一个样本文档，可是我们怎么知道对不对呢�Q�因此需要输出来看一下。我们将JDOM生成的文档输出到控制収ͼ�使用 JDOM �?XMLOutputter �c�R�?/p>
5. ��?JDOM 转化�?XML 文本

XMLOutputter xmlOut = new XMLOutputter(" ",true);
try {
xmlOut.output(myDocument,System.out);
} catch (IOException e) {
e.printStackTrace();
}
XMLOutputter 有几个格式选项。这里我们已指定希望子元素从父元素羃�q�两个空��|��q�且希望元素间有�I��?br>new XMLOutputter(java.lang.String indent, boolean newlines)�q�个�Ҏ��在最新版本中已经不徏议��用。JDOM有一个专门的用来定义格式化输出的�c�：org.jdom.output.Format�Q�如果你没有�Ҏ��的要求，有时候��用里面的几个静态方法（应该可以说是预定义格式）�?getPrettyFormat()��可以了。我们把上面的输出格式稍微改一下，��p��q�样�Q?br>XMLOutputter xmlOut = new XMLOutputter(Format.getPrettyFormat());

6.��JDOM文档转化为其他�Ş�?/p>
XMLOutputter �q�可输出�?Writer �?OutputStream。�ؓ了输出JDOM文档��C��个文本文�Ӟ��我们可以�q�样做：
FileWriter writer = new FileWriter("/some/directory/myFile.xml");
outputter.output(myDocument, writer);
writer.close();

XMLOutputter �q�可输出到字�W�串,以便�E�序后面�q�行再处�?
Strng outString = xmlOut.outputString(myDocument);

当然�Q�在输出的时候你不一定要输出所有的整个文档�Q�你可以选择元素�q�行输出�Q?br>xmlOut.output(rootElement.getChild("name"),System.out);
一句话�Q�JDOM非常灉|��方便�Q�如果你惌��一步研�I�JDOM�Q�请到官方网站去看一看：http://www.jdom.org

本节�C�Z��源码�Q?br>package com.cyberobject.study;

import java.io.IOException;

import org.jdom.Attribute;
import org.jdom.Content;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.output.Format;
import org.jdom.output.XMLOutputter;

/**
* @author kingwong
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class TestJDOM {

public static void main(String[] args)
{
Element rootElement = new Element("MyInfo");
Document myDocument = new Document(rootElement);

// Attribute rootAttri = new Attribute("comment","introduce myself");
// rootElement.setAttribute(rootAttri);

rootElement.setAttribute("comment","introduce myself");
//rootElement.setAttribute(new Attribute("comment","introduce myself"));
// Element sexElement = new Element("sex");
// rootElement.addContent(sexElement);

// Element nameElement = new Element("name");
// nameElement.addContent("kingwong");
// rootElement.addContent(nameElement);

rootElement.addContent((Content)(new Element("name").addContent("kingwong")));
rootElement.addContent(new Element("sex").setAttribute("value","male"));
rootElement.addContent((Content)(new Element("contract").addContent((Content)(new Element("telephone").addContent("87654321")))));

rootElement.removeChild("sex");

XMLOutputter xmlOut = new XMLOutputter(Format.getPrettyFormat());
try {
xmlOut.output(myDocument,System.out);
//xmlOut.output(rootElement.getChild("name"),System.out);
//String outString = xmlOut.outputString(myDocument);
} catch (IOException e) {
e.printStackTrace();
}
}
}

�Q�二�Q�、XML文档解析

JDOM 不光可以很方便的建立XML文档�Q�它的另一个用处是它能够读取�ƈ操作现有�?XML 数据�?br>JDOM的解析器在org.jdom.input.*�q�个包里�Q�其中的DOMBuilder的功能是��DOM模型的Document解析成JDOM模型的Document�Q�SAXBuilder的功能是从文件或��中解析出符合JDOM模型的XML树。由于我们经常要从一个文仉��d��数据�Q�因此我们应该采用后者作��析工兗��?br>解析一个xml文档�Q�基本可以看成以下几个步骤：

1.实例化一个合适的解析器对�?/p>
本例中我们��用SAXBuilder:
SAXBuilder sb = new SAXBuilder();

2.以包含XML数据的文件�ؓ参数�Q�构��Z��个文档对象myDocument

Document myDocument = sb.build(/some/directory/myFile.xml);

3.获到根元�?/p>
Element rootElement = myDocument.getRootElement();

一旦你获取了根元素�Q�你��可以很方便地对它下面的子元素进行操作了�Q�下面对Element对象的一些常用方法作一下简单说明：
getChild("childname") �q�回指定名字的子节点,如果同一�U�有多个同名子节点，则只�q�回�W�一个；如果没有�q�回null倹{�?br>getChildren("childname") �q�回指定名字的子节点List集合。这样你��可以遍历所有的同一�U�同名子节点�?
getAttributeValue("name") �q�回指定属性名字的倹{��如果没有该属性则�q�回null,有该属性但是��gؓ�I�，则返回空字符丌Ӏ?br>getChildText("childname") �q�回指定子节点的内容文本倹{�?br>getText() �q�回该元素的内容文本倹{�?/p>
�q�有其他没有�|�列出来的方法，如果需要的话，可以随时查阅JDOM的在�U�文档：http://www.jdom.org/docs/apidocs/index.html。当然你可以在你需要的地方��d��、删除元素操作，�q�记得上面的创徏XML的方法吗�Q�呵呵~~~

学习��C��东还是从实例学�v最为快��P��下面��单�D个例子，��׃��上面的XML��h��代码来学习JDOM的XML解析。本例中��d��了样本XML文�g里一些属性和content�Q�最后我们还在contact元素里插入了一个新元素wanghua@cyberobject.com" />。尽��我们实��C��对于XML的基本操作，�l�心的朋友可能会
有疑问：如果XML文档的层�ơ稍微复杂一些，如果嵌套多达几十上百层的话（开个玩�W�）�Q�如果靠�q�样从根元素一�U�一�U�地通过getChild("childname")来访问子元素的话�Q�将会非常痛苦！是的�Q�的��是�q�样�Q�但是我们有另一个有力的工具XPath�Q��ؓ什么不用呢�Q�这是后话！先卖个关子（手敲累啦�Q�下回吧�Q�呵呵）�?/p>
/*
* Created on 2004-8-21
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package com.cyberobject.study;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
import org.jdom.output.Format;
import org.jdom.output.XMLOutputter;

/**
* @author kingwong
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class TestJDOM2 {
public static void main(String[] args){
SAXBuilder sb = new SAXBuilder();
try
{
Document doc = sb.build("myFile.xml");
Element root = doc.getRootElement();

String str1 = root.getAttributeValue("comment");
System.out.println("Root Element's comment attribute is : " + str1);
String str2 = root.getChild("sex").getAttributeValue("value");
System.out.println("sex Element's value attribute is : " + str2);
String str3 = root.getChildText("name");
System.out.println("name Element's content is :" + str3);
String str4 = root.getChild("contact").getChildText("telephone");
System.out.println("contact Element's telephone subelement content is : " + str4 + "\n");
Element inputElement = root.getChild("contact");
inputElement.addContent(new Element("email").setAttribute("value","wanghua@cyberobject.com"));

XMLOutputter xmlOut = new XMLOutputter(Format.getPrettyFormat());
String outStr = xmlOut.outputString(root);
System.out.println(outStr);
}
catch(Exception e)
{
e.printStackTrace();
}
}
}

草儿 2007-06-25 18:33 发表评论

草儿 — Wed, 06 Jun 2007 13:31:00 GMT

Groovy tries to be as natural as possible for Java developers. We've tried to follow the principle of least surprise when designing Groovy, particularly for developers learning Groovy who've come from a Java background.

Here we list all the major differences between Java and Groovy.

Default imports

All these packages and classes are imported by default, i.e. you do not have to use an explicit import statement to use them:

java.io.*
java.lang.*
java.math.BigDecimal
java.math.BigInteger
java.net.*
java.util.*
groovy.lang.*
groovy.util.*

Common gotchas

Here we list the common things you might trip over if you're a Java developer starting to use Groovy.

== means equals on all types. In Java there's a wierd part of the syntax where == means equality for primitive types and == means identity for objects. Since we're using autoboxing this would be very confusing for Java developers (since x == 5 would be mostly false if x was 5 . So for simplicity == means equals() in Groovy. If you really need the identity, you can use the method "is" like foo.is(bar). This does not work on null, but you can still use == here: foo==null.
in is a keyword. So don't use it as a variable name.
When declaring array you can't write

int[] a = {1,2,3};

you need to write

int[] a = [1,2,3]

If you were used to write a for loop which looked like

for (int i =0; i < len; i++)

in groovy you need to write

for (i in 0..len-1)

or

for (i in 0..

Things to be aware of

semicolon is optional. Use them if you like (though you must use them to put several statements on one line).
the return keyword is optional.
you can use the this keyword inside static methods (which refers to this class).
methods and classes are public by default.
protected in Groovy is the equivalent of both package-protected and protected in Java. i.e. you can have friends in the same package - or derived classes can also see protected members.
inner classes are not supported at the moment. In most cases you can use closures instead.
the throws clause in method heads is not checked by the Groovy compiler, because there is no difference between checked and unchecked exceptions.

Uncommon Gotchas

Java programmers are used to semicolons terminating statements and not having closures. Also there are instance initializers in class definitions. So you might see something like:

class Trial { private final Thing thing = new Thing ( ) ; { thing.doSomething ( ) ; } }

Many Groovy programmers eschew the use of semicolons as distracting and redundant (though others use them all the time - it's a matter of coding style). A situation that leads to difficulties is writing the above in Groovy as:

class Trial { private final thing = new Thing ( ) { thing.doSomething ( ) } }

This will probably be a compile error!

The issue here is that in this situation the newline is not a statement terminator so the following block is treated as a closuresthat is a parameter to the Thing constructor. Bizarre to many, but true. If you want to use instance initializers in this sort of way, it is effectively mandatory to have a semicolon:

class Trial { private final thing = new Thing ( ) ; { thing.doSomething ( ) }

This way the block following the initialized definition is clearly an instance initializer.

New features added to Groovy not available in Java

closures
native syntax for lists and maps

GroovyMarkup and GPath support
native support for regular expressions
polymorphic iteration and powerful switch statement

dynamic and static typing is supported - so you can omit the type declarations on methods, fields and variables
you can embed expressions inside strings
lots of new helper methods added to the JDK
simpler syntax for writing beans for both properties and adding event listeners

safe navigationusing the ?. operator, e.g. "variable?.field" and "variable?.method()" - no more nested ifs to check for null clogging up your code

草儿 2007-06-06 21:31 发表评论

生成一个java�~�制的可执行文�g[1]

草儿 — Tue, 01 May 2007 09:04:00 GMT

��java�~�织�?class后，如果只是用java 命��o来执行总觉得不是太�q�瘾�Q�找个办法生成像exe文�g一��L��鼠标双击便可执行的文�Ӟ��应该是很有趣的啊。本文主要介�l�了一�U�生成java可执行程序的�Ҏ��?

�q�里我用了一个名字叫做exe4j的免费小软�g�Q�感觉不错。下面我��我把java�?class文�g生成可执行文件的��程讲一下�?

首先�Q�将你要选择好你卛_��发布�?class文�g��׃��用细说了�Q�下面是创徏jar文�g�Q�这里我用一个名字叫做test.class的文件来举例�Q�另外注意还要编写一个确定main_class的文件manifest.mf�Q�在�q�里mainfest.mf和test.class是在同一个目录下�Q�然后��用如下命�?

jar cvfm test.jar manifest.mf test

�q�样�Q�一个test.jar文�g��q��成了�Q�这里我��׃��l�说jar的具体功能了。但��Z��保成功�Q�我们可以再用下面的指��o执行一下刚刚生成的test.jar�Q?

java -jar test.jar

怎么��P��是不是可以很��利的进行？如果是，那我们就可以开始进行可执行文�g的创��Z��?

下面打开exe4j�Q�它的开始一个界面是�q�样的：

http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-291439280.jpg
单击NEXT键，选择”JAR in EXE”mod按钮�Q�单击NEXT�Q?

http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-291439282.jpg
出现下面画面�Q�填写短名和文�g输出的�\径然后点击NEXT�l�箋
http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-291439284.jpg
你又会看��C��面的画面�Q�在�q�里你可以选择你要生成的可执行文�g的类型，以及生成的可执行文�g名称、可执行文�g的图标等�Q�我们在�q�里��选择GUI application�Q�名字就�Ҏ��自己的需要取一个，图标你可以自己在你的图标库里选一个你喜欢的，然后再NEXT再��l�；

http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-291439286.jpg
下一个画面如下，在这里填写Main class的名字，单击下面的绿�?选择所需�?jar文�g,如果没有�Ҏ��要求我们��可以再�l�箋了；

http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-291439288.jpg
接下来是选择版本的画面，填写好自��q��最大最��版本然后再�l�箋
http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-2914392810.jpg
下面�q�个画面可以帮助你设一下你的文件执行的片头�Q�增加其��观效果�Q�选择自己喜欢的图片，写自己想写的文字�Q��ƈ可以�Ҏ��需要调整文字的位置�Q�再�l�箋

http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-2914392812.jpg
下面是一个选择语言版本的界面选好后再�l�箋
http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-2914392814.jpg
下面是一个短暂的�{�待
http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-2914392816.jpg
然后��大功告成了�Q�一个java写成的可执行文�g��p��L��成了
http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-2914392818.jpg
��M��下看看效果，�q�面而来的是自己讄��的开头效果，感觉怎么�?
http://dev.csdn.net/Develop/ArticleImages/21/21845/CSDN_Dev_Image_2003-10-2914392820.png

草儿 2007-05-01 17:04 发表评论

草儿 — Fri, 09 Mar 2007 04:56:00 GMT
     摘要: 一、Java基础知识1.Java有那些基本数据类型，String是不是基本数据类型，他们有何区别�?.字符串的操作�Q��?写一个方法，实现字符串的反�{�Q�如�Q�输入abc�Q�输出cba 写一个方法，实现字符串的替换�Q�如�Q�输入bbbwlirbbb�Q�输出bbbhhtccc�?.数据�c�d��之间的�{换�?如何��数值型字符转换为数字（Integer�Q�Double�Q��?如何��数字�{换�ؓ字符如何取小数点前两位，�q�四...  阅读全文

草儿 2007-03-09 12:56 发表评论

Eclipse 快捷�?指南

草儿 — Fri, 09 Mar 2007 04:46:00 GMT
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草儿 2007-03-09 12:46 发表评论

草儿 — Fri, 12 Jan 2007 07:33:00 GMT

Conclusion

This tutorial showed you how to create an SQL realm and deploy a Web application that uses the realm. In this example, you used DB2 Express-C as the database and the Eclipse Web Tools Platform for the development environment to create an application and deploy it to WebSphere Application Server Community Edition for hosting the application.

Acknowledgements

The author would like to thank Manu T. George (WebSphere Application Server Community Edition L3 Support) and Anitha Krishnasamy (WebSphere Application Server Community Edition Business Development) for reviewing this tutorial and providing their valuable comments.

Download

Description Name Size Download method

Sample code for this tutorial sample-db2-realm.zip 28KB HTTP

Resources

Learn

Kick-start your Java apps

WebSphere Application Server Community Edition resources

Get products and technologies

Download WebSphere Application Server Community Edition V1.1

Download DB2 Express-C

Download Eclipse

About the author

Krishnakumar Balachandar is a senior staff software engineer at IBM Software labs in Bangalore, India. He is part of the support team for Geronimo and WebSphere Community Edition.

草儿 2007-01-12 15:33 发表评论

草儿 — Fri, 12 Jan 2007 05:37:00 GMT

Krishnakumar Balachandar (krishnakumarb@in.ibm.com), Software Engineer, WebSphere Application Server Community Edition Support Team, IBM

20 Sep 2006

This tutorial shows you how to set up an SQL realm to implement database security for a Web application using the no-charge Java kick-start package.

Before you start

When implementing security in a Web application, a JAAS module is required to specifically handle user authentication and authorization. WebSphere Application Server Community Edition provides a SQL realm that can connect to a database for obtaining user credentials. In this tutorial, you will see how to set up tables for creating an SQL realm in DB2 Express-C, how to set up a development environment using the Eclipse Web Tooling Platform to create a Web application, and how to deploy the Web application to WebSphere Application Server Community Edition from Eclipse.

All Web applications should employ some level of security for user authentication and authorization to verify a user’s identity and enable access to application functions that are applicable to the user's role.

Web applications can use LDAP, database, file system, Kerberos, or other such systems to provide authentication and authorization. To access security data from the selected method or system, an SQL realm is set up by creating tables in a database and configuring a Java Authentication and Authorization Service (JAAS) module to access these tables from an application server.

Figure 1 shows different components in WebSphere Application Server Community Edition (hereafter referred to as Community Edition) used to provide an SQL realm. The Web application uses an SQL realm that connects to the database using a pool or driver. The user credentials are stored in tables in the database and are fetched when calls are made using the JAAS SQL realm.

Figure 1. Components of an SQL realm

Java Authentication and Authorization Service (JAAS) is a set of APIs that enables Java applications to access authentication and access control services without being tied to the service it is using. Using JAAS, the Java application can plug into security mechanisms like LDAP, Kerberos, databases, and so on, providing a layer between our application and the security mechanism being used.

Setting up a database realm

Setting up a database realm involves performing these general steps:

Create tables for users and groups in DB2 Express-C.

Deploy a database pool in Community Edition, if the realm is going to use a pool to connect to the database.

Deploy the SQL realm plan in Community Edition.

Configure and deploy the Web application that uses the SQL realm.

The remainder of this tutorial explains these tasks in detail.

Setting up a database

In this section, you will see how to set up the database and database tables required for the SQL realm. You can create database and tables either by using the Control Center or by running an SQL script.

Using the Control Center

Create the database

In DB2 Express-C, open the Control Center.

Right-click All Databases, then select Create Database => Standard.

For Database name, enter WASCE.

Click Finish.

You just created a new database called WASCE and should see it listed under All Databases (Figure 2).

Figure 2. New database created

Back to top

Create tables

Now, create the tables for users (USERS) and groups (GROUPS) in the new WASCE database:

Under WASCE in the directory listing, right-click Tables, then select Create.

For Table name, enter USERS, then click Next.

Add a column:
Select Add to add a column to the new table.
For Column name, enter USERNAME.
For Data type, select VARCHAR.
For Nullable or not, select No.
Click Apply.

Repeat step 3 to add an EMAIL column and a PASSWORD column to the USERS table, with the values shown in Figure 3. When finished, click OK.

Repeat steps 1 through 4 to create a new GROUPS table with two columns: GROUPNAME and USERNAME.

Click Next => Next => Next to get to the Define keys on new table panel.

Select Add Primary. From the available columns, select which column is to be the primary key for each table:
For the USERS table, select USERNAME, and for the GROUPS table, select USERNAME/GROUPNAME as the primary key.
For the GROUPS table, select Add foreign => USERNAME. Click the > button to move it to foreign key. Select USERNAME as the primary key in the Parent table (Schema/Name - ADMINISTRATOR/USERS).

Click Finish and the table is created.

Use the steps above and the schema definitions shown in Figures 3 and 4 to create the USERS and GROUPS tables. For the USERS table, USERNAME is the primary key. For the GROUPS table, GROUPNAME and USERNAME are primary keys, and USERNAME is a foreign key (referring to USERNAME in the USERS table).

Figure 3. USERS schema

Figure 4. GROUPS schema

In the steps shown above, the USERS and GROUPS tables are created under the ADMINISTRATOR schema. Had you logged in as db2admin, the tables would be created under the DB2ADMIN schema.

Populate tables with values

Select WASCE => Tables => USERS.

Right-click on the USERS table, then select Open => Add row.

Enter test values for each field in the database record, then select Commit.

Repeat steps 2 and 3 for each test record you wish to create, then Close.

Repeat steps 1 through 4 for the GROUPS table (Figure 5).

Figure 5. Create test data records

Using scripts

As an alternative to using the DB2 Control Center, you can create the database, tables, and test data using an SQL script. The download file included with this tutorial contains a sanmple script file, db2_realm.sql. Execute this script from DB2 command line to create the database and tables:

Open a Windows command window or run the DB2 batch file /bin/db2cw.bat.

Execute the sample script file with this command: db2 -tvfdb2-realm.sql.

If there are no errors, success messages will be generated for the SQL (Figure 6).

Figure 6. Create database, tables, and test data using script

Creating the Web application

In this section, you will use the Eclipse Web Tools Platform (WTP) to create a simple Web application. Before you begin with the application, though, you will need to define a new server in Eclipse (to which the new application will be deployed) and create a Java Runtime Environment (JRE). After that, you can use Eclipse WTP to create the application components (like the WAR and EAR files). The download file included with this tutorial contains a source EAR file of a sample application that you can import into Eclipse WTP.

Define a new server

To deploy an application, you need to define a server in Eclipse:

In Eclipse, right-click the Server tab, and select New Server to open the New Server wizard (Figure 7).

Figure 7. Define new server

Select WebSphere Application Server Community v1.1 Server, then press Next.

Enter values for all fields, as shown in Figure 8, then Finish.

Figure 8. New server parameters

Create a JRE

To build application for supported Java Runtime Environment (JRE), in this case the IBM JRE, you need to configure the JRE in Eclipse WTP:

In Eclipse, select Window => Preferences.

Select Java => Installed JREs.

Click Add. . .

On the Add JRE dialog, enter values for all fields, as shown in Figure 9.

Figure 9. Add JRE

Be sure this JRE is selected as the default JRE.

Next, you need to make sure that the IBM JRE will run the new server that you created earlier. Right-click on the new server, then select Open (Figure 10).

Figure 10. Open new server

Next to Runtime, select Edit.

For JRE, select IBM (Figure 11), then Finish.

Figure 11. Select IBM JRE

Develop an application

The Web application will contain pages for the application (in a WAR file) and will be added to an enterprise application (in an EAR file). For the purposes of this tutorial, you can either use an application you develop from scratch, or you can use the sample application included in the download file.

Create a new application in Eclipse WTP

Run Eclipse WTP either by double-clicking eclipse.exe from the location where you extracted the WTP platform, or by executing eclipse.exe from a command line.

Select File => New => Project => Web =>Dynamic Web Project.

On the Dynamic Web Project dialog, enter or select the following values:
Project name: SQLRealmWeb
Target runtime: WebSphere Community Edition v1.1
EAR membership: SQLRealmApp

If you need to create a WebSphere Application Server Community Edition V1.1 runtime option (Figure 12):
Click the New button next to Target Runtime.
Select WebSphere Application Server Community Edition v1.1, then Next.
Select IBM for JRE, and browse to the appropriate Application Server Install Directory, then click Finish.

Figure 12. Create Community Edition runtime

Click Next on the next two panels.

For Context Root, enter /SQLRealmWeb, then Next.

Configure the Geronimo deployment plan by entering these values:
Group ID: wasce
Artifact ID: sqlrealm
Version: 1.0
Artifact Type: WAR

Click Finish (Figure13).

Figure 13. Server setup complete

Import sample application into Eclipse WTP

If you choose to import the sample project, the download file included with this tutorial contains an EAR file you can import into the Eclipse WTP workspace:

In Eclipse, select File => Import => J2EE.

For Source File, enter SQLRealmAppSrc.ear, then click Next.

Enter or select the following values:
EAR Project: SQLRealmApp
Web Project: SQLRealmWeb
Target Runtime: WebSphere Community Edition v1.1

If you need to create a WebSphere Application Server Community Edition V1.1 runtime option (Figure 12):
Click the New button next to Target Runtime.
Select WebSphere Application Server Community Edition v1.1, then Next.
Select IBM for JRE, and browse to the appropriate Application Server Install Directory, then click Finish.

Click Finish.

Deploying the application

With the application created, you can deploy it to the Community Edition runtime environment. However, for the application to run, you need a database pool and realm plan:

Deploy the database pool

To connect to DB2, you need a database pool, which you can create by deploying a database pool plan with the wizard that is available from the Community Edition administrative console:

Logon to the Community Edition administrative console by starting the server. To start the server, right-click on the new server you created above, and select Start. Once the server is started, the status changes to green and shows "Started". You can now launch the console by right-clicking on the started server and selecting Launch Community Edition Console. Enter your username and password as system and manager.

Under Services, select Database Pools => Using Geronimo PoolsWizard.

For Database Pools, enter Db2Realm, then Next.

On the Select Driver, JAR, Parameters panel, enter or select the values shown for all fields in Figure 14. When finished, click Next.

Figure 14. Enter database pool parameters

Test the connection for errors by selecting Test connection. If there are no errors, you will see the message: Test Result: Connected to DB2/NT SQL09000 in the console.

Once you deploy the pool, it is started and running (Figure 15).

Figure 15. Database pool deployed

Deploy the realm plan

Community Edition connects to SQL databases using JAAS, by default, to provide an SQL realm to applications deployed in the server. You can make this connection by using a JDBC driver that connects directly to the database, or by using a database pool that gets a connection from a pool to connect to the database.

The realm plan (see Listings 1 and 2) is used to deploy an SQL realm that connects to the database. The realm plan contains Geronimo GBeans required to create an SQL realm. The GBean "sql-login" has attributes that you use to specify the realm type, loginModuleClass = org.apache.geronimo.security.realm.providers.SQLLoginModule, and options where you specify the JDBC properties required to connect to the database. You can use this plan to connect to any JDBC database. For this exercise, you can specify either the JDBC driver or the DataSource name to connect to the database.

Using the JDBC driver

Listing 1 shows an SQL realm plan that uses the JDBC driver to connect to database. The plan is contained in the download file as sqlplan.xml. In the statements that are bold in Listing 1, replace ADMINISTRATORS with the schema name in which the tables have been created.

Listing 1. SQL realm plan using JDBC driver

db2 realm 1.0 car geronimo j2ee-security 1.1 car console.dbpool DB2Realm 1.0 rar org.apache.geronimo. security.realm.providers.SQLLoginModule true jdbcUser=db2admin jdbcPassword=db2admin jdbcURL=jdbc:db2:WASCE jdbcDriver=com.ibm.db2.jcc.DB2Driver userSelect=select username, password from ADMINISTRATOR.USERS groupSelect=select groupname, username from ADMINISTRATOR.GROUPS sql-realm sql-realm sql-login ServerInfo JaasLoginService REQUIRED sql-login sqltest sql-realm JaasLoginService

Using database pool

Listing 2 shows an SQL realm plan that uses a database pool (DB2Realm) that was deployed using the console wizard. The plan is contained in the download file as sqlpoolplan.xml.

Listing 2. SQL realm plan using database pool

db2 pool-realm 1.0 car geronimo j2ee-security 1.1 car console.dbpool DB2Realm 1.0 rar org.apache.geronimo.security.realm. providers.SQLLoginModule true userSelect=select username, password from ADMINISTRATOR.USERS groupSelect=select groupname, username from ADMINISTRATOR.GROUPS dataSourceName=DB2Realm sqlpool-realm sqlpool-realm sqlpool-login ServerInfo JaasLoginService REQUIRED sqlpool-login sqlpooltest

Deploy the realm

You can deploy the realms to the server using the administrative console:

Start the Community Edition server from Eclipse WTP. In Eclipse, select the server you created earlier by right-clicking on the Server tab, then select Start (Figure 16).

Figure 16. Start server

Login to the Community Edition administrative console.

Deploy the SQL realm plan that uses JDBC Driver (sqlplan.xml shown in Listing 1) by selecting Deploy New on the console (Figure 17).

Figure 17. Deploy database realm

Deploy the SQL database realm plan that uses the database pool (sqlpoolplan.xml shown in Listing 2).

Check to see that these two plans are deployed successfully by selecting Systems Modules under Applications in the console (Figure 18).

Figure 18. Check successful real deployment

Deploy the application

With the application and server configuration defined in Eclipse, and the database realm deployed, you can now deploy the application to the server.

In Community Edition, select Server tab, right-click on the server you created earlier, and then select Add and Remove Projects.

Select the SQLRealmApp from the Available projects list and click Add > to move it over to the Configured projects list (Figure 19).

Click Finish.

Figure 19. Add to configured projects

Start the server. From the Server tab, right-click again on your server and select Start. The application will run on the server you selected.

To launch the console for the server, right-click on the Community Edition server, then select Launch Community Edition Console. Enter the login ID and password: system and manager, respectively (Figure 20).

Figure 20. Launch administrative consoles

Running the application
In the prior sections, you created and deployed the Web application to the server from Eclipse WTP. Next, you can use the application, following the instructions in this section to test authentication, authorization, and access to the database pool. The application referred to in this section is the sample application provided in the download file.
Access the application
To access the Web application:
From the Eclipse Navigator, right-click the Web application SQLRealmWeb, then select Run As => Run on Server.
Select WebSphere Application Server Community Edition 1.1, which is the server you defined earlier.
The project should already be added. Select Next and Finish.
The application should now be available at http://localhost:8080/SQLRealmWeb/ (Figure 21).

Figure 21. Test the application

Test the authentication
Included with this sample application are several valid user ID and password combinations (for testing authentication) with different roles (for testing authorization). Test the authentication by logging in. Using a correct user ID and password will log you in. An incorrect user ID and password will display the error page shown in Figure 22.
Valid user ID/password values are as follows:
system/manager admin/admin123 user1/user1123 user2/user2123 guest1/guest1123 guest2/guest2123

Figure 22. Application error page

Test authorization
Once authenticated and inside the application, the user is allowed access to areas of Web application based on the user's business role, as defined in the deployment descriptor. The sample application is defined with three roles: admin, user, and guest. A user with an admin role has access to all accounts in the sample application, but a user with a guest role will only be able to access pages defined for the guest. Test this by entering the application with different user IDs and passwords with admin, user, and guest roles. Figure 23 shows a user logged in as admin, but who is able to view the guest pages.

Figure 23. Admin user viewing Guest page

In the case of unauthorized access (for example, if a guest user attempts to access a page authorized for admin users only), an HTTP 403 status error occurs (Figure 24) and prevents access to the page.

Figure 24. Authorization error

Using the database pool
The default Web application is configured to use SQL realm that uses the JDBC driver. You can change this so that it uses the database pool by changing the realm name in the geronimo-web.xml file as sqlpool-realm, and republishing the server. Verify if this works by stopping the db2/realm/1.0/car configuration in the server.
Contents of the download file
The download file included with this tutorial, sample-db2-realm.zip, contains the following files:
db2-realm.sql - SQL script file to create database and tables
db2-plan.xml - Plan to deploy a DB2 database pool.
sqlplan.xml - SQL realm plan that uses JDBC driver.
sqlpoolplan.xml - SQL realm plan that uses a database pool.
SQLRealmAppSrc.ear - Source for sample Web application.

草儿 2007-01-12 13:37 发表评论


		Krishnakumar Balachandar is a senior staff software engineer at IBM Software labs in Bangalore, India. He is part of the support team for Geronimo and WebSphere Community Edition.