异常总结

Tomcat发布项目时:
Exception loading sessions from persistent storage


删除Tomcat里面的work\Catalina\localhost下的内容即可解决

SSH
Illegal access: this web application instance has been stopped already.  Could not load com.mysql.jdbc.SQLError.  The eventual following stack trace is caused by an error thrown for debugging purposes as well as to attempt to terminate the thread which caused the illegal access, and has no functional impact.

这个不是问题，是由于this web application instance has been stopped already，不用管它


org.apache.jasper.JasperException: javax.servlet.ServletException: javax.servlet.jsp.JspException: Cannot retrieve mapping for action /userLogon

是由于在struts-config.xml没有配置相应的 action 的原因
如：
<action path="/userLogon" type="com.userManagement.action.UserLogonAction" name="userForm"></action>

项目右击->java build Path ：
Build path contains duplicate entry: XXX

说明项目中有重复的包，删掉即可


严重: IOException while loading persisted sessions: java.io.EOFException

是Tomcat启动时读取硬盘上的Session失败，是Tomcat本身的异常，不影响项目，解决方法，把Tomcat目录中的work文件夹清空