登录模块出错啊，我想知道是代码问题，还是数据库问题，错误代码如下

Question

严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
    at com.yourcompany.struts.action.LoginAction.execute(LoginAction.java:50)
    at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
    at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
    at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
    at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at com.jspdev.biyesheji.EncodingFilter.doFilter(EncodingFilter.java:29)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
    at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:864)
    at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:579)
    at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1665)
    at java.lang.Thread.run(Thread.java:619)

 

浏览器：type Exception report

message 

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

exception 

javax.servlet.ServletException: java.lang.NullPointerException
    org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:535)
    org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:433)
    org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
    org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    com.jspdev.biyesheji.EncodingFilter.doFilter(EncodingFilter.java:29)


root cause 

java.lang.NullPointerException
    com.yourcompany.struts.action.LoginAction.execute(LoginAction.java:50)
    org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:431)
    org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:236)
    org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
    org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    com.jspdev.biyesheji.EncodingFilter.doFilter(EncodingFilter.java:29)


note The full stack trace of the root cause is available in the Apache Tomcat/6.0.32 

Answer 1

[quote]
java.lang.NullPointerException

at com.yourcompany.struts.action.LoginAction.execute(LoginAction.java:50)
[/quote]
日志中说得很清楚了，LoginAction这个类的第50行出现了空指针异常，打个断点调试一下。