Neither the JAVA_HOME nor the JRE_HOME environment variable is defined

先讲一个Tomcat的问题。很多人兴冲冲的下载了一个Tomcat，跑到bin看到一个startup.bat就去执行，结果提示Neither the JAVA_HOME nor the JRE_HOME environment variable is defined At least one of these environment variable is needed to run this program。好，再去下载个最新版本的JDK,Install完成之后却还是提示Neither the JAVA_HOME nor the JRE_HOME environment variable is defined At least one of these environment variable is needed to run this program。搞得对Tomcat的学习热情冷了一半。 

原因是后来较新版本的JDK（例如我使用的JDK1.6）安装完不会自动登记环境变量JAVA_HOME，JRE_HOME。像我在单位的环境，我的用户是受限制的(PowerUser)，不方便设环境变量，于是我就找到了另外一个方法。 

先看Tomcat的startup.bat，它调用了catalina.bat,而catalina.bat则调用了setclasspath.bat。只要在setclasspath.bat的开头声明环境变量，如我的就是：

 rem ---------------------------------------------------------------------------

rem Set CLASSPATH and Java options
rem
rem $Id: setclasspath.bat 505241 2007-02-09 10:22:58Z jfclere $
rem ---------------------------------------------------------------------------

set JAVA_HOME=D:\Java\jdk1.6.0_11
set JRE_HOME=D:\Java\jre6

rem Make sure prerequisite environment variables are set
if not "%JAVA_HOME%" == "" goto gotJdkHome
if not "%JRE_HOME%" == "" goto gotJreHome
echo Neither the JAVA_HOME nor the JRE_HOME environment variable is defined
echo At least one of these environment variable is needed to run this program
goto exit
...... 

这样在每次运行startup.bat时就注册了JAVA_HOME，JRE_HOME。控制台窗口关闭后，这两个变量也将消失，不会再占用内存。运行一下，最终提示“信息：Server startup in xxxxx ms”就大功告成了。

转自：http://www.cnblogs.com/nuke/archive/2009/05/11/1454039.html