?? ? ? 最近同事在碰到一個棘手的問題,用了一天還是調試不出到底哪里出錯了,郁悶中時老大過來就說了一個很好的解決方法,用日志跟蹤.沒過半小時,問題就找到了,定位很準確.這讓我看到日志的重要性了.
?????? 一開始我還是寫一些log的,但是那時候覺得好像沒什么必要,后來就從來沒有寫過,因為我想不出他的好處.現在在知道日志真正的作用,而且也是一個很強大 的工具.平時在寫代碼的時候,花個幾秒鐘寫個log,也許會覺得很煩,但是我覺得還是值得的.
?????? 這也是一個習慣的問題,好的程序員之所以是個好的程序員是因為他有好的習慣,這些好的習慣帶來的好處也是很多的.寫日志只是其中一個好習慣,我也要慢慢留意一些好的習慣,慢慢總結.

??? ?? Quartz作為一個開源的作業調度框架，已經廣泛應用于j2ee中，在這里提供一些資料以供參考：
??? ?? 首先是官方網站：http://www.opensymphony.com/quartz/ 這里可以下載源代碼，還有論壇，jira等最原始的資料。?? ??
??? ?? 一個寫的不錯的介紹Quartz的中文文章：詳細講解Quartz如何從入門到精通，英文不好的可以參考這個。這篇文章大致的講了Quartz的框架，很多細節并沒有涉及，這也難怪，一篇文章不可能都寫上去的。
??? ?? 如果你想繼續了解Quartz，官方網站有面向開發人員的文檔，但是放在不起眼的角落，我以前閑逛時找到，現在一時找不到，什么時候什么找到了在加上去，我在 另外地方找到其中的幾章，這兩章是其中最重要的兩章，可以作為參考，http://javaforge.com/proj/doc.do?doc_id= 1740
??? ?? 如果你還要繼續深入研究，就請自己到cvs去下載最新源碼，自己研讀了，祝大家成功，我會接下去寫一些自己從中學到的東西。

在完全剛裝好的fc4上用jdbc進行數據庫操作出現了一下錯誤：
?java.net.SocketException: Invalid argument or cannot assign requested address
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:305)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:171)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:158)
at java.net.Socket.connect(Socket.java:452)
at java.net.Socket.connect(Socket.java:402)
at java.net.Socket.<init>(Socket.java:309)
at java.net.Socket.<init>(Socket.java:124)?
?????? 這是IP地址的問題,在FC4中默認的是IPv6 socket,JDK1.4支持的應該是IPv4,具體原因可以查看SUN公司給出的解釋.
解決辦法是在運行JAVA程序時加上 -Djava.net.preferIPv4Stack=true 如:

java -Djava.net.preferIPv4Stack=true application.

但是這個在每次都要加上這句話，另有解決方法是 修改 /etc/modprobe.conf 文件,增加

alias net-pf-10 off
alias ipv6 off

這樣就不用增加參數 "-Djava.net.preferIPv4Stack=true ",重起即可.

但是既要ipv6又能解決這個問題的方法還沒找到。希望高人指點

附：最近在弄cc，也找了一些ant資料，順便轉載記錄一下

轉自http://ant.apache.org/manual/OptionalTasks/junit.html

JUnit

Description

This task runs tests from the JUnit testing framework. The latest version of the framework can be found at http://www.junit.org. This task has been tested with JUnit 3.0 up to JUnit 3.8.1; it won't work with versions prior to JUnit 3.0.

Note: This task depends on external libraries not included in the Ant distribution. See Library Dependencies for more information.

Note: You must have junit.jar and the class files for the <junit> task in the same classpath. You can do one of:

1. Put both junit.jar and the optional tasks jar file in ANT_HOME/lib.
2. Do not put either in ANT_HOME/lib, and instead include their locations in your CLASSPATH environment variable.
3. Do neither of the above, and instead, specify their locations using a <classpath> element in the build file. See the FAQ for details.

Tests are defined by nested test or batchtest tags (see nested elements).

Parameters

Attribute	Description	Required
printsummary	Print one-line statistics for each testcase. Can take the values on, off, and withOutAndErr. withOutAndErr is the same as on but also includes the output of the test as written to System.out and System.err.	No; default is off.
fork	Run the tests in a separate VM.	No; default is off.
forkmode	Controls how many Java Virtual Machines get created if you want to fork some tests. Possible values are "perTest" (the default), "perBatch" and "once". "once" creates only a single Java VM for all tests while "perTest" creates a new VM for each TestCase class. "perBatch" creates a VM for each nested <batchtest> and one collecting all nested <test>s. Note that only tests with the same settings of filtertrace, haltonerror, haltonfailure, errorproperty and failureproperty can share a VM, so even if you set forkmode to "once", Ant may have to create more than a single Java VM. This attribute is ignored for tests that don't get forked into a new Java VM. since Ant 1.6.2	No; default is perTest.
haltonerror	Stop the build process if an error occurs during the test run.	No; default is off.
errorproperty	The name of a property to set in the event of an error.	No
haltonfailure	Stop the build process if a test fails (errors are considered failures as well).	No; default is off.
failureproperty	The name of a property to set in the event of a failure (errors are considered failures as well).	No.
filtertrace	Filter out Junit and Ant stack frames from error and failure stack traces.	No; default is on.
timeout	Cancel the individual tests if they don't finish in the given time (measured in milliseconds). Ignored if fork is disabled.	No
maxmemory	Maximum amount of memory to allocate to the forked VM. Ignored if fork is disabled.	No
jvm	The command used to invoke the Java Virtual Machine, default is 'java'. The command is resolved by java.lang.Runtime.exec(). Ignored if fork is disabled.	No; default is java.
dir	The directory in which to invoke the VM. Ignored if fork is disabled.	No
newenvironment	Do not propagate the old environment when new environment variables are specified. Ignored if fork is disabled.	No; default is false.
includeantruntime	Implicitly add the Ant classes required to run the tests and JUnit to the classpath in forked mode. Note: Please read the Ant FAQ if you want to set this to false and use the XML formatter at the same time.	No; default is true.
showoutput	Send any output generated by tests to Ant's logging system as well as to the formatters. By default only the formatters receive the output.	No
tempdir	Where Ant should place temporary files. Since Ant 1.6.	No; default is the project's base directory.
reloading	Whether or not a new classloader should be instantiated for each test case. Ignore if fork is set to true. Since Ant 1.6.	No; default is true.

By using the errorproperty and failureproperty attributes, it is possible to perform setup work (such as starting an external server), execute the test, clean up, and still fail the build in the event of a failure.

The filtertrace attribute condenses error and failure stack traces before reporting them. It works with both the plain and XML formatters. It filters out any lines that begin with the following string patterns:

   "junit.framework.TestCase"
   "junit.framework.TestResult"
   "junit.framework.TestSuite"
   "junit.framework.Assert."
   "junit.swingui.TestRunner"
   "junit.awtui.TestRunner"
   "junit.textui.TestRunner"
   "java.lang.reflect.Method.invoke("
   "sun.reflect."
   "org.apache.tools.ant."

Nested Elements

The <junit> task supports a nested <classpath> element that represents a PATH like structure.

jvmarg

If fork is enabled, additional parameters may be passed to the new VM via nested <jvmarg> elements. For example:

<junit fork="yes">
  <jvmarg value="/-Djava.compiler=NONE"/>
  ...
</junit>

would run the test in a VM without JIT.

<jvmarg> allows all attributes described in Command-line Arguments.

sysproperty

Use nested <sysproperty> elements to specify system properties required by the class. These properties will be made available to the VM during the execution of the test (either ANT's VM or the forked VM, if fork is enabled). The attributes for this element are the same as for environment variables.

<junit fork="no">
  <sysproperty key="basedir" value="${basedir}"/>
  ...
</junit>

would run the test in ANT's VM and make the basedir property available to the test.

syspropertyset

You can specify a set of properties to be used as system properties with syspropertysets.

since Ant 1.6.

env

It is possible to specify environment variables to pass to the forked VM via nested <env> elements. For a description of the <env> element's attributes, see the description in the exec task.

Settings will be ignored if fork is disabled.

bootclasspath

The location of bootstrap class files can be specified using this PATH like structure - will be ignored if fork is not true or the target VM doesn't support it (i.e. Java 1.1).

since Ant 1.6.

permissions

Security permissions can be revoked and granted during the execution of the class via a nested permissions element. For more information please see permissions

Settings will be ignored if fork is enabled.

since Ant 1.6.

assertions

You can control enablement of Java 1.4 assertions with an <assertions> subelement.

Assertion statements are currently ignored in non-forked mode.

since Ant 1.6.

formatter

The results of the tests can be printed in different formats. Output will always be sent to a file, unless you set the usefile attribute to false. The name of the file is determined by the name of the test and can be set by the outfile attribute of <test>.

There are three predefined formatters - one prints the test results in XML format, the other emits plain text. The formatter named brief will only print detailed information for testcases that failed, while plain gives a little statistics line for all test cases. Custom formatters that need to implement org.apache.tools.ant.taskdefs.optional.junit.JUnitResultFormatter can be specified.

If you use the XML formatter, it may not include the same output that your tests have written as some characters are illegal in XML documents and will be dropped.

Note: Please read the Ant FAQ if you want to set the fork attribute to true, the includeAntRuntime attribute to false and use the XML formatter at the same time.

Attribute	Description	Required
type	Use a predefined formatter (either xml, plain, or brief).	Exactly one of these.
classname	Name of a custom formatter class.
extension	Extension to append to the output filename.	Yes, if classname has been used.
usefile	Boolean that determines whether output should be sent to a file.	No; default is true.
if	Only use formatter if the named property is set.	No; default is true.
unless	Only use formatter if the named property is not set.	No; default is true.

test

Defines a single test class.

Attribute	Description	Required
name	Name of the test class.	Yes
fork	Run the tests in a separate VM. Overrides value set in <junit>.	No
haltonerror	Stop the build process if an error occurs during the test run. Overrides value set in <junit>.	No
errorproperty	The name of a property to set in the event of an error. Overrides value set in <junit>.	No
haltonfailure	Stop the build process if a test fails (errors are considered failures as well). Overrides value set in <junit>.	No
failureproperty	The name of a property to set in the event of a failure (errors are considered failures as well). Overrides value set in <junit>.	No
filtertrace	Filter out Junit and Ant stack frames from error and failure stack traces. Overrides value set in <junit>.	No; default is on.
todir	Directory to write the reports to.	No; default is the current directory.
outfile	Base name of the test result. The full filename is determined by this attribute and the extension of formatter.	No; default is TEST-name, where name is the name of the test specified in the name attribute.
if	Only run test if the named property is set.	No
unless	Only run test if the named property is not set.	No

Tests can define their own formatters via nested <formatter> elements.

batchtest

Define a number of tests based on pattern matching.

batchtest collects the included files from any number of nested <fileset>s. It then generates a test class name for each file that ends in .java or .class.

Attribute	Description	Required
fork	Run the tests in a separate VM. Overrides value set in <junit>.	No
haltonerror	Stop the build process if an error occurs during the test run. Overrides value set in <junit>.	No
errorproperty	The name of a property to set in the event of an error. Overrides value set in <junit>.	No
haltonfailure	Stop the build process if a test fails (errors are considered failures as well). Overrides value set in <junit>.	No
failureproperty	The name of a property to set in the event of a failure (errors are considered failures as well). Overrides value set in <junit>	No
filtertrace	Filter out Junit and Ant stack frames from error and failure stack traces. Overrides value set in <junit>.	No; default is on.
todir	Directory to write the reports to.	No; default is the current directory.
if	Only run tests if the named property is set.	No
unless	Only run tests if the named property is not set.	No

Batchtests can define their own formatters via nested <formatter> elements.

Examples

<junit>
  <test name="my.test.TestCase"/>
</junit>

Runs the test defined in my.test.TestCase in the same VM. No output will be generated unless the test fails.

<junit printsummary="yes" fork="yes" haltonfailure="yes">
  <formatter type="plain"/>
  <test name="my.test.TestCase"/>
</junit>

Runs the test defined in my.test.TestCase in a separate VM. At the end of the test, a one-line summary will be printed. A detailed report of the test can be found in TEST-my.test.TestCase.txt. The build process will be stopped if the test fails.

<junit printsummary="yes" haltonfailure="yes">
  <classpath>
    <pathelement location="${build.tests}"/>
    <pathelement path="${java.class.path}"/>
  </classpath>

  <formatter type="plain"/>

  <test name="my.test.TestCase" haltonfailure="no" outfile="result">
    <formatter type="xml"/>
  </test>

  <batchtest fork="yes" todir="${reports.tests}">
    <fileset dir="${src.tests}">
      <include name="**/*Test*.java"/>
      <exclude name="**/AllTests.java"/>
    </fileset>
  </batchtest>
</junit>

Runs my.test.TestCase in the same VM, ignoring the given CLASSPATH; only a warning is printed if this test fails. In addition to the plain text test results, for this test a XML result will be output to result.xml. Then, for each matching file in the directory defined for ${src.tests} a test is run in a separate VM. If a test fails, the build process is aborted. Results are collected in files named TEST-name.txt and written to ${reports.tests}.