忘了配置哪出的错了

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后来上网找到了解决方案：只要把JAVA_HOME/lib/tools.jar拷到TOMCAT_HOME/common/lib下，重启动
Tomcat，就可以了