Question

使用ssh框架做的一个项目，结果运行时报错。。。

严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at com.service.DeptServiceImpl.chekUser(DeptServiceImpl.java:19)
at com.web.action.LoginAction.execute(LoginAction.java:29)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:484)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:274)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1482)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:525)
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 org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:75)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
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.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:619)

Answer 1

DeptService ds = (DeptService)cxt.getBean("dsi");

仔细检查配置文件，可能ds值为null

Answer 2

com.service.DeptServiceImpl.chekUser(DeptServiceImpl.java:19)
看这里是不是调什么DAO了，但又没注入。

Answer 3

空指针,dao层方法没有注入吧

Answer 4

DeptServiceImpl 第19行，空指针。那个对象我猜是user。呵呵。

Answer 5

空指针你页面 的参数传过来没。打个断点 看下 接受的参数 USER对象是否为NULL

Answer 6

把LoginAction.java第29行上下代码贴出来

追问

LoginForm lf= (LoginForm)form;
WebApplicationContext cxt = WebApplicationContextUtils.getWebApplicationContext(this.getServlet().getServletContext());
DeptService ds = (DeptService)cxt.getBean("dsi");
第29行： if(ds.chekUser(lf)){
List depts = ds.getAll();
request.setAttribute("depts", depts);
return mapping.findForward("success");
}