??xml version="1.0" encoding="utf-8" standalone="yes"?>国产精品日韩精品,在线中文av,屁屁影院在线观看 http://www.aygfsteel.com/Annebaby/zh-cn Tue, 29 Jul 2025 12:52:57 GMT Tue, 29 Jul 2025 12:52:57 GMT 60 linix和Windows安装JDK所配置的环境变?/title> http://www.aygfsteel.com/Annebaby/articles/335737.html和贝?/dc:creator>和贝?/author>Wed, 20 Oct 2010 16:25:00 GMT http://www.aygfsteel.com/Annebaby/articles/335737.html http://www.aygfsteel.com/Annebaby/comments/335737.html http://www.aygfsteel.com/Annebaby/articles/335737.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335737.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335737.html 在linux下:
JAVA--HOME=/opt/jdk1.6.0-10
CLASSPATH=.:$JAVA-HOME/jre/lib/rt.jar
PATH=.:$JAVA-HOME/bin
在windows下:
JAVA-HOME=C:\Program Files\java\jdk1.6.0-10(q个Ҏ(gu)自己存储的地址讄Q是一个模式。比如我的\径是Q?font size="6">D:\Java\jdk)
CLASSPATH=.:%JAVA-HOME%\jre\lib\rt.jar
PATH=%JAVA_HOME%\bin;%JAVA_HOME%\jre\bin; ........
]]> 引用cd的变量和普通类型的变量区别 http://www.aygfsteel.com/Annebaby/articles/335734.html和贝?/dc:creator>和贝?/author>Wed, 20 Oct 2010 16:11:00 GMT http://www.aygfsteel.com/Annebaby/articles/335734.html http://www.aygfsteel.com/Annebaby/comments/335734.html http://www.aygfsteel.com/Annebaby/articles/335734.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335734.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335734.html
2.引用cd变量可以使用“.”操作Q比如this.nameQ,来访问它所指向对象的方法或属性?br />
]]> Super与this区别 http://www.aygfsteel.com/Annebaby/articles/335640.html和贝?/dc:creator>和贝?/author>Tue, 19 Oct 2010 15:35:00 GMT http://www.aygfsteel.com/Annebaby/articles/335640.html http://www.aygfsteel.com/Annebaby/comments/335640.html http://www.aygfsteel.com/Annebaby/articles/335640.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335640.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335640.html 区别 super this
范围 是由子类讉K父类的内?nbsp; 是直接访问本cM的内?/span>
讉K属?nbsp; super.父类属性,如果属性没有被覆写Q则也可?nbsp; this本类属?br />
不写super
讉KҎ(gu) super.父类Ҏ(gu)(),如果Ҏ(gu)没有被覆写,则可?nbsp; this.本类Ҏ(gu)(),可以不写this,也表C用本cȝ
不用 加super也表C用父cM的方?br />
讉K构?nbsp; super是访问父cM的构造方法,必须攑֜首行 this 是访问本cM的其他构造,必须攑֜首行
比如Q?br />
class People{
String name;
int age;
public People(String name,int age){
this.name=name;
this.age=age;
}
public String fun(){
return ""+name+age;
}
}
class Student extends People{
String school;
public Student(String name,int age,String school){
super(name,age);
this.school=school;
}
public void print(){
System.out.println(fun()+this.school);
}
}
public class Demo(){
public ststic void main(String[] args){
Student s = new Student("Lucy",21,"理工");
s.print();
}
}
]]>JavaE序分类 http://www.aygfsteel.com/Annebaby/articles/335393.html和贝?/dc:creator>和贝?/author>Sun, 17 Oct 2010 15:14:00 GMT http://www.aygfsteel.com/Annebaby/articles/335393.html http://www.aygfsteel.com/Annebaby/comments/335393.html http://www.aygfsteel.com/Annebaby/articles/335393.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335393.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335393.html
Java AppletQ作为没有main()Ҏ(gu)的入口,由浏览器?p:colorscheme colors="#ffffff,#000000,#808080,#000000,#bbe0e3,#333399,#009999,#99cc00">
appletviewer加蝲执行
]]> Stringcȝ一些用?/title> http://www.aygfsteel.com/Annebaby/articles/335378.html和贝?/dc:creator>和贝?/author>Sun, 17 Oct 2010 14:22:00 GMT http://www.aygfsteel.com/Annebaby/articles/335378.html http://www.aygfsteel.com/Annebaby/comments/335378.html http://www.aygfsteel.com/Annebaby/articles/335378.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335378.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335378.html
2.String有两U赋值方式(直接赋值和用new开辟空_
3.String是Java中共享模式的一U应?br />
在这里D一个例子:
public class Text{
public static void main(String[] args){
String st="abc";
System.out.println("abd".equals(st));
}
}
其中“abc”是String的匿名对象,StringcM的内容一旦声明则不可改变。比如:
public class Text{
public static void main(String[] args){
String str1="abc";
str1+="def";
System.out.println(str1);
}
}
q行l果为abcdeg,q程如下QString str1="abc",证明栈内存中有个str1Q在堆内存中的内Ҏ(gu)str1+="def";首先是先?#8220;def”在堆内存中开辟空_然后再进行str1+"def"q算所得的字符?#8220;abcdef”又在堆内存开辟一个空间。原来str1所占的堆内存空_现在str1+"def"q算所得的字符又赋lstr1,所以str1先断开指向“abc”的连接,最后就指向“abcdef”新的I间与其建立q接?br />
虽然以上昄String的内Ҏ(gu)变了Q但是实际上而言QString改变的只是其内存地址的指向,而其本n的内Ҏ(gu)有被改变。所以说q样写代码媄响程序的性能?br />
问题Q只要是字符串就是一个String匿名对象吗?
在StringcM如果一个字W串已经明确了一个对象的指向Q则以后其他的String对象如果声明的内Ҏ(gu)一LQ则自动指向同一个空间?br />
比如:
public class Text{
public static void main(String[] args){
String str1="abc";
String str2="abc";
System.out.println(str1==str2);
}
}
原来?/span>“ abc” 有没被引用到Q我们知道原来的 “ abc” 已经?/span>str1引用Q?那么׃可能再生成另外一?/span>“ abc” , 只会原来的 “ abc” 地址指向 str2Q那现在 str1?/span>str2都指向同一个内存空间地址Q?span style="font-family: 宋体">比如 “ abc” 内存I间地址?/span>0x1000哈,我们q行 System.out.println(str1==str2);
代码中进?/span>“ ==” 比较时得到的q算l果是 true了, 所以说如果内存中已l有相同内容的地址话,我们׃要再开辟新的空间了Q?span style="font-family: 宋体">如果没有的话Q那我们p重新声明开辟新的空间?/span>
?/span>String str1 = new String( “ abc ” ) ; 代码中我们知?/span>“ abc ” 是匿名对象,那么在堆内存中就 会有块空间是 “ abc ” Q紧接着 new String("abc") 使用 new 在堆内存中又开辟了一个空?/span>“ abc ” , 最?/span>String str1 = new String("abc") ; 代码最后生成的 “ abc ” 内存地址指向 str1, 最 早的一?/span>“ abc ” 没使用上?/span>
]]> Ҏ(gu)的覆写与Ҏ(gu)的重载的区别Q?/title> http://www.aygfsteel.com/Annebaby/articles/335372.html和贝?/dc:creator>和贝?/author>Sun, 17 Oct 2010 13:25:00 GMT http://www.aygfsteel.com/Annebaby/articles/335372.html http://www.aygfsteel.com/Annebaby/comments/335372.html http://www.aygfsteel.com/Annebaby/articles/335372.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335372.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335372.html
重写 / 覆写( Override ): 是发生在l承关系之中Q是由子c进行覆写的;Ҏ(gu)名称相同Q参数的cd或个数相同,Ҏ(gu)的访问权限不严格.
Ҏ(gu)的复写D例:
class A
{
public void fun(){}
}
class B extends A
{
public void fun(){}
}
fun被子cd写了 注意Q子cd写父cȝҎ(gu)Ӟ被复写的Ҏ(gu)不能比父cL有更严格的访问权限?nbsp; 卛_果我们把AcMfun()Ҏ(gu)的访问权限修Ҏ(gu)defaultQ则此时BcMfun()Ҏ(gu)的访问权限比Acd。被复写后父cM的方法被子类Ҏ(gu)覆盖。一个特D情况,如果父类中fun()Ҏ(gu)讉K权限为privateQ子cȝ讉K权限为defaultQ明说Q这不叫复写Q因为父cM的fun()Ҏ(gu)子类看不见即父类被重写的Ҏ(gu)被覆盖?
]]> 基本数据cd占用的存储空?/title> http://www.aygfsteel.com/Annebaby/articles/335313.html和贝?/dc:creator>和贝?/author>Sat, 16 Oct 2010 13:53:00 GMT http://www.aygfsteel.com/Annebaby/articles/335313.html http://www.aygfsteel.com/Annebaby/comments/335313.html http://www.aygfsteel.com/Annebaby/articles/335313.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335313.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335313.html
cd
占用存储I间
byte boolean
1字节
short char
2字节
int float
4字节
long double
8字节
注:点型常量默认ؓDouble型,如要声明一个常量ؓfloat型,则在候命加F或f。而String是引用类?br />
2010q?0?6?/div>
]]> JVM(Java Virtual Machine) http://www.aygfsteel.com/Annebaby/articles/335311.html和贝?/dc:creator>和贝?/author>Sat, 16 Oct 2010 13:45:00 GMT http://www.aygfsteel.com/Annebaby/articles/335311.html http://www.aygfsteel.com/Annebaby/comments/335311.html http://www.aygfsteel.com/Annebaby/articles/335311.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335311.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335311.html
垃圾回收机制攑֜JVM里,由JVM完全负责回收事宜Q即Java垃圾回收释放内存是Javaq行pȝ自己自动完成的,不需要程序员q预Q程序员也无法干预,负责回收的是垃圾回收器。当一个对象不再有M一个引用变量指向它Ӟq个对象׃被垃圑֛收机制回收了。就是说Q当在堆内存中的某一对象没有M引用Ӟ意呛_意味着告诉JVM“不要q个对象Q可以回收了”。JVM的垃圑֛收机制对堆空间做实时监测?br />
Java虚拟机的本质是实现Java代码在不同操作系l下都可以执行即Java的跨q_Q可以实?#8220;一ơ编写,到处执行”的效果。JavaE序先经q编写生?java源程序,然后l过Java~译器编译生?class字节码,q时q行虚拟机,虚拟Z启动cd载器Q然后类加蝲器会扑ֈAPT中相对应的类q行加蝲Q进行匹配后Q再q行字节码校验,解释器进行解释,最后交l操作系l控制硬件执行?br />
2010q?0?6?br />
]]> cd对象的联p?/title> http://www.aygfsteel.com/Annebaby/articles/335170.html和贝?/dc:creator>和贝?/author>Thu, 14 Oct 2010 11:42:00 GMT http://www.aygfsteel.com/Annebaby/articles/335170.html http://www.aygfsteel.com/Annebaby/comments/335170.html http://www.aygfsteel.com/Annebaby/articles/335170.html#Feedback 0 http://www.aygfsteel.com/Annebaby/comments/commentRss/335170.html http://www.aygfsteel.com/Annebaby/services/trackbacks/335170.html
ȝQ类是一个抽象的Q一个共性的东西Q对象是cȝ一个具体应用,是一个个性的东西?br />
比如Z个Peoplec?在类中描qChh的某U特征和行ؓ。h都有姓名q龄{属性,Z吃饭睡觉跑步{行为,q是对h的一个抽象的描述。如果对于张三,q是针对具体某个人的Q他们有具体的姓名年龄,也有PeoplecLh的行为,所以他是People的一个对象?br />
]]>
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