今天配置 Eclipse下配置tomcat  
server时报出异常  The Tomcat installation directory is not valid. It is missing
expected file or folder lib/jasper-el.jar 解决办法如下:The Tomcat installation directory is not valid. It is missing expected file or folder lib/jasper-el_tomcat 点击Download
and install 按操作完成。该问题解决。