Eclipse使用Ant编译时报错Perhaps JAVA_HOME does not point to the JDK

Ant编译时报错，内容如下：

com.sun.tools.javac.Main is not on the classpath.
Perhaps JAVA_HOME does not point to the JDK.
It is currently set to "D:\Java_Tools\Java\jre7"

解决，需要指定Eclipse编译时JREs，根据提示，应指定到JDK

如下图，点击window--> preferences--> Java --> Installed JREs ，点击Add，选择电脑中安装的jdk路径，此处选择jdk路径而不是jre路径，然后勾选新增加的jdk，确定，重新编译即可。