HTTP Status 500 -
type Exception report

message

description The server encountered an internal error that prevented it from fulfilling this request.

exception

java.lang.NullPointerException
	cn.zzw.mess.servlet.UserServlet.doPost(UserServlet.java:82)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:650)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
	cn.zzw.mess.filter.MyFilter.doFilter(MyFilter.java:27)
note The full stack trace of the root cause is available in the Apache Tomcat/7.0.69 logs.