可能重复：
ant 错误 JAVA_HOME 未指向 SDK
我收到以下错误：
BUILD FAILED C:\Users\myname\Documents\CMSC\Proj1\build.xml:22: Unable to find a javac compiler; com.sun.tools.javac.Main is not on the classpath. Perhaps JAVA_HOME does not point to the JDK. It is currently set to "C:\Program Files (x86)\Java\jre7" Total time: 1 second
我的 build.xml 文件包含以下代码：
<project name="Project1" default="compile" basedir=".">
<description>
Build file for Project1
</description>
<!-- global properties for this build file -->
<property name="source.dir" location="src"/>
<property name="build.dir" location="bin"/>
<property name="doc.dir" location="doc"/>
<property name="main.class" value="proj1.Project1"/>
<!-- set up some directories used by this project -->
<target name="init" description="setup project directories">
<mkdir dir="${build.dir}"/>
<mkdir dir="${doc.dir}"/>
</target>
<!-- Compile the java code in ${src.dir} into ${build.dir} -->
<target name="compile" depends="init" description="compile java sources">
<javac srcdir="${source.dir}" destdir="${build.dir}"/>
</target>
<!-- execute the program with the fully qualified name in ${build.dir} -->
<target name="run" description="run the project">
<java dir="${build.dir}" classname="${main.class}" fork="yes">
<arg line="${args}"/>
</java>
</target>
<!-- Delete the build & doc directories and Emacs backup (*~) files -->
<target name="clean" description="tidy up the workspace">
<delete dir="${build.dir}"/>
<delete dir="${doc.dir}"/>
<delete>
<fileset defaultexcludes="no" dir="${source.dir}" includes="**/*~"/>
</delete>
</target>
<!-- Generate javadocs for current project into ${doc.dir} -->
<target name="doc" depends="init" description="generate documentation">
<javadoc sourcepath="${source.dir}" destdir="${doc.dir}"/>
</target>
</project>
我在这里做错了什么？它似乎试图在我的 src 文件夹中找到一个 javac 文件，但我不知道如何解决这个问题。