3招解决ant构建时任务找不到(taskdef cann't be found)的问题

在用ant编译项目时，有时会碰到build.xml中所定义的任务找不到的问题：

[root@tivu25 test]# ant -f build.xml local_war
Buildfile: build.xml

local_war:

BUILD FAILED
/home/haoqf/software/APM/test/build.xml:18: taskdef class com.ibm.team.build.ant.task.LogPublisherTask cannot be found

Total time: 0 seconds

这是因为ant在当前java的classpath中找不到类LogPublisherTask（LogPublisherTask由 org.apache.tools.ant.Task派生而来），这时候需要重新指定当前的classpath，让它包含LogPublisherTask所属jar库或者class的路径。有三种方法：
1. 在ant命令行指定：

[root@tivu25 test]# ant -f build.xml local_war -lib /home/haoqf/software/RTC/RTC-BuildSystem-Toolkit-Linux-3.0iFix1/jazz/buildsystem/buildtoolkit/

2. 在build.xml指定：

<?xml version="1.0" encoding="UTF-8"?>

<project name="BVT_CVT" default="local_war">

     <target name="local_war">
        <taskdef name="logPublisher" classname="com.ibm.team.build.ant.task.LogPublisherTask">
        <classpath>
            <pathelement location="/home/haoqf/software/RTC/RTC-BuildSystem-Toolkit-Linux-3.0iFix1/jazz/buildsystem/buildtoolkit/"/>
            <fileset dir="/home/haoqf/software/RTC/RTC-BuildSystem-Toolkit-Linux-3.0iFix1/jazz/buildsystem/buildtoolkit/">
                <include name="**/*.jar"/>
            </fileset>
        </classpath>
        </taskdef>

        <logPublisher repositoryAddress="${repositoryAddress}"    />

     </target>
</project>

3. 设定当前环境变量CLASSPATH：

[root@tivu25 test]# export CLASSPATH=$CLASSPATH:/home/haoqf/software/RTC/RTC-BuildSystem-Toolkit-Linux-3.0iFix1/jazz/buildsystem/buildtoolkit/com.ibm.team.build.toolkit_2.2.0.v20110308_0258.jar

其中com.ibm.team.build.toolkit_2.2.0.v20110308_0258.jar包含了类LogPublisherTask的实现。