java.lang.NoClassDefFoundError ANT build

Question

我在运行阶段遇到类路径错误.错误是

run:
    [java] java.lang.NoClassDefFoundError: org/openqa/selenium/WebDriver
    [java]  at java.lang.Class.getDeclaredMethods0(Native Method)
    [java]  at java.lang.Class.privateGetDeclaredMethods(Unknown Source)
    [java]  at java.lang.Class.privateGetMethodRecursive(Unknown Source)
    [java]  at java.lang.Class.getMethod0(Unknown Source)
    [java]  at java.lang.Class.getMethod(Unknown Source)
    [java]  at sun.launcher.LauncherHelper.validateMainClass(Unknown Source)
    [java]  at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
    [java] Caused by: java.lang.ClassNotFoundException: org.openqa.selenium.WebDriver
    [java]  at java.net.URLClassLoader.findClass(Unknown Source)
    [java]  at java.lang.ClassLoader.loadClass(Unknown Source)
    [java]  at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    [java]  at java.lang.ClassLoader.loadClass(Unknown Source)
    [java]  ... 7 more
    [java] Error: A JNI error has occurred, please check your installation and try again
    [java] Exception in thread "main" 
    [java] Java Result: 1
BUILD SUCCESSFUL
Total time: 1 second

这是我编写的xml构建代码.我正在引用RunningPower jars文件夹,我相信正在引用正确的文件夹,因为我能够编译.我的基本目录还包含.classpath和.project文件,但不确定它们是否重要.

 <?xml version="1.0" ?>

<project name="SeleniumProjectDataDriven" basedir="." default="run">
    <target name="init">
        <property name="src.dir" value="src" />
        <property name="build.dir" value="build" />
        <property name="classes.dir" value="${build.dir}/class" />
        <property name="lib.dir" value="RunningPowerJars" />
    </target>

    <target name="clean" depends="init">
         <delete dir="build"/>
     </target>

    <target name="compile" description="Compiles the code" depends="clean" >
        <mkdir dir="${classes.dir}" />
        <javac srcdir="${src.dir}" destdir="${classes.dir}" includeantruntime="false">
            <classpath>
                <fileset dir="${lib.dir}">
                    <include name="**/*.jar" />
                </fileset>
            </classpath>
        </javac>
    </target>

    <target name="jar" description="Packages the code into jar" depends="compile">
        <mkdir dir="build/jar"/>
            <jar destfile="build/jar/RunningPower.jar" basedir="build/class">
                <manifest>
                    <attribute name="Main-Class" value="RunningPower"/>
                </manifest> 
            </jar> 
    </target>

    <target name="run" description="Run the jar file" depends="jar" >
        <java jar="build/jar/RunningPower.jar" fork="true"/>
    </target>
</project>

在我的RunningPowerJars文件夹中,它们包含

junit-4.8.1.jar
ojdbc6.jar
poi-3.7-20101029.jar
selenium-java-2.46.0.jar
selenium-server-standalone-2.46.0.jar
testng-6.1.1.jar

更新(太平洋标准时间上午7:32 8/21/2015)

<target name="run" description="Run the jar file" depends="jar" >
    <java jar="build/jar/RunningPower.jar" fork="true">
        <classpath>
            <fileset dir="${lib.dir}">
            <include name="**/*.jar" /> 
            </fileset> 
        </classpath>
    </java>
</target>

我修改了代码但遇到了另一个错误.

BUILD FAILED
C:\Users\dt208672\Perforce\depot\ebill\Automation\Selenium_eBill\RunningPower\build.xml:37: Problem: failed to create task or type classpath
Cause: The name is undefined.
Action: Check the spelling.
Action: Check that any custom tasks/types have been declared.
Action: Check that any <presetdef>/<macrodef> declarations have taken place.

Answer 1

运行Jar文件时也需要类路径,以便JVM可以找到库类.但是,jar在java任务中使用该属性时,"忽略所有类路径设置"(请参阅https://ant.apache.org/manual/Tasks/java.html).最简单的方法是指定主类并添加已编译的Jar以及位于RunningPowerJars目录中的库Jars :

<target name="run" description="Run the jar file" depends="jar" >
    <java classname="RunningPower" fork="true">
       <classpath>
            <pathelement location="build/jar/RunningPower.jar"/>
            <fileset dir="${lib.dir}">
                <include name="**/*.jar" />
            </fileset>
        </classpath>
   </java>
</target>

一个不相关的注意事项是您可以使用init整个构建文件中定义的属性.例如,在jar目标中,您可以使用${classes.dir}而不是重复build/class.

如果在使用属性时classpath在java任务内添加元素,构建将失败的原因仍然没有意义jar.尽管它被忽略了,但是由于"创建任务或类型失败"错误而失败是很奇怪的.