类Action继承DispatchAction的问题

Question

类Action继承DispatchAction的问题我写了一个登陆程序。Action类是如下方式
public class LoginAction extends DispatchAction {
public ActionForward selectOneUser(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response) throws Exception {
// TODO Auto-generated method stub
String name=request.getParameter("name");
LoginForm loginForm = LoginImplFactory.getLoginInstance().selectOneUser(name);
if(loginForm==null){
request.setAttribute("errors", "用户名不存在");
return mapping.findForward("login_failure");
}else if(!loginForm.getPassword().equals(request.getParameter("password"))){
request.setAttribute("errors", "密码不正确");
return mapping.findForward("login_failure");
}else{
request.setAttribute("person", loginForm);
return mapping.findForward("login_success");
}
}
}
Login.jsp    主要代码如下：<html:form action="login.do?method=selectOneUser">...</form>
但是无法运行,错误如下：

Answer 1

配置文件如下：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.2//EN" "http://struts.apache.org/dtds/struts-config_1_2.dtd"><struts-config>
  <data-sources />
  <form-beans >
    <form-bean name="loginForm" type="org.shuye100.struts.form.LoginForm" />  </form-beans>  <global-exceptions />
  <global-forwards />
  <action-mappings >
    <action
      attribute="loginForm"
      input="/login.jsp"
      name="loginForm"
      path="/login"
      scope="request"
      type="org.shuye100.struts.action.LoginAction" >
      <forward name="login_success" path="/login_success.jsp"/>
      <forward name="login_failure" path="/login_failure.jsp"/>
      </action>  </action-mappings>  <message-resources parameter="org.shuye100.struts.ApplicationResources" />
</struts-config>

Answer 2

错误如下：
HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: DispatchMapping[/login] does not define a handler property
org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:176)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.13 logs.
--------------------------------------------------------------------------------Apache Tomcat/6.0.13

Answer 3

后台错误如下：
严重: DispatchMapping[/login] does not define a handler property
2007-11-9 11:16:00 org.apache.struts.action.RequestProcessor processException
警告: Unhandled Exception thrown: class javax.servlet.ServletException
2007-11-9 11:16:00 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
javax.servlet.ServletException: DispatchMapping[/login] does not define a handler property
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:176)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)

Answer 4

  <action 
            --这里少了一个参数
              parameter="method"
            attribute= "loginForm " 
            input= "/login.jsp " 
            name= "loginForm " 
            path= "/login " 
            scope= "request " 
            type= "org.shuye100.struts.action.LoginAction "   > 
            <forward   name= "login_success "   path= "/login_success.jsp "/> 
            <forward   name= "login_failure "   path= "/login_failure.jsp "/> 
            </action> 

Answer 5

不行啊！加了parameter= "method " 以后重启tomcat还是出错！如下：
警告: Unhandled Exception thrown: class java.lang.NullPointerException
2007-11-9 11:27:57 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at org.shuye100.struts.action.LoginAction.selectOneUser(LoginAction.java:45)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:274)
at org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:194)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
at org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Unknown Source)

Answer 6

8楼正解,parameter= "method " 
这个必须有.

Answer 7

HTTP Status 500 - --------------------------------------------------------------------------------type Exception reportmessage 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:523)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:421)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
root cause java.lang.NullPointerException
org.shuye100.struts.action.LoginAction.selectOneUser(LoginAction.java:45)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
java.lang.reflect.Method.invoke(Unknown Source)
org.apache.struts.actions.DispatchAction.dispatchMethod(DispatchAction.java:274)
org.apache.struts.actions.DispatchAction.execute(DispatchAction.java:194)
org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1194)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:710)
javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.13 logs.
--------------------------------------------------------------------------------

Answer 8

LoginAction的selectOneUser方法的４５行报出的空指针啊，这个不是配置问题！
既然是登录，那你写的这是什么意思？String　name=request.getParameter( "name "); 
LoginForm　loginForm　=　LoginImplFactory.getLoginInstance().selectOneUser(name);应该提交表单的时候在form里面取值，而不是request范围内，getParameter("name")这个方法是得到url地址后的值，如:/login.do?method=selectOneUser&name="test",得到name的值为test.

Answer 9

sdfsdf