struts1.3 问题 Unhandled exception

Question

感谢帮助错误信息
警告: Unhandled exception
java.lang.NullPointerException
at org.apache.struts.config.FormBeanConfig.createActionForm(FormBeanConfig.java:289)
at org.apache.struts.config.FormBeanConfig.createActionForm(FormBeanConfig.java:357)
at org.apache.struts.chain.commands.CreateActionForm.execute(CreateActionForm.java:92)
at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:305)
at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
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.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:128)
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:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Thread.java:619)
2009-12-20 4:07:27 org.apache.struts.chain.commands.ExceptionCatcher postprocess
警告: Exception from exceptionCommand 'servlet-exception'
java.lang.NullPointerException
at org.apache.struts.config.FormBeanConfig.createActionForm(FormBeanConfig.java:289)
at org.apache.struts.config.FormBeanConfig.createActionForm(FormBeanConfig.java:357)
at org.apache.struts.chain.commands.CreateActionForm.execute(CreateActionForm.java:92)
at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:305)
at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
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.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:128)
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:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Thread.java:619)
2009-12-20 4:07:27 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet action threw exception
java.lang.NullPointerException
at org.apache.struts.config.FormBeanConfig.createActionForm(FormBeanConfig.java:289)
at org.apache.struts.config.FormBeanConfig.createActionForm(FormBeanConfig.java:357)
at org.apache.struts.chain.commands.CreateActionForm.execute(CreateActionForm.java:92)
at org.apache.struts.chain.commands.ActionCommandBase.execute(ActionCommandBase.java:51)
at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
at org.apache.commons.chain.generic.LookupCommand.execute(LookupCommand.java:305)
at org.apache.commons.chain.impl.ChainBase.execute(ChainBase.java:191)
at org.apache.struts.chain.ComposableRequestProcessor.process(ComposableRequestProcessor.java:283)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1913)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:449)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
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.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:128)
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:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:849)
web.xml<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
xmlns="http://java.sun.com/xml/ns/j2ee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
  <servlet>
   <servlet-name>action</servlet-name>
   <servlet-class>org.apache.struts.action.ActionServlet</servlet-class>
      
   <init-param>
<param-name>config</param-name>
<param-value>/WEB-INF/struts-config.xml</param-value>  
   </init-param>
   <load-on-startup>2</load-on-startup>
  </servlet>
  
  <servlet-mapping>
   <servlet-name>action</servlet-name>
   <url-pattern>*.do</url-pattern>
  </servlet-mapping>
  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>
struts-config.xml<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts-config PUBLIC "-//Apache Software Foundation//DTD Struts Configuration 1.1//EN" "http://jakarta.apache.org/struts/dtds/struts-config_1_1.dtd"><struts-config> <form-beans>
<form-bean name="LoginForm" type="com.zxl.test.form.LoginForm"></form-bean>
</form-beans>

<global-forwards />

<action-mappings>
<action path="/login" type="com.zxl.test.action.LoginAction"  name="LoginForm">
<forward name="success" path="/success.jsp" />
<forward name="fail" path="/fail.jsp" />
</action>
</action-mappings>

<message-resources parameter="ApplicationResources" />
</struts-config>LoginAction.javapackage com.zxl.test.action;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;import org.apache.struts.action.Action;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;import com.zxl.test.AccountBean;
import com.zxl.test.from.LoginForm;public class LoginAction extends Action{ public ActionForward execute(ActionMapping mapping, ActionForm form,
HttpServletRequest request, HttpServletResponse response)
throws Exception {
LoginForm loginForm=(LoginForm)form;
AccountBean ab=new AccountBean();
String userName=loginForm.getUserName();
String password=loginForm.getPassword();
ab.setUserName(userName);
ab.setPassword(password);

if(userName.equals("admin") && password.equals("admin")){
return mapping.findForward("success");
}else{
return mapping.findForward("fail");
}
}
}LoginForm.javapackage com.zxl.test.from;import javax.servlet.http.HttpServletRequest;import org.apache.struts.action.ActionErrors;
import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.action.ActionMessage;public class LoginForm extends ActionForm{
private String userName;
private String password;


public void reset(ActionMapping mapping, HttpServletRequest request) {
userName=null;
password=null;
}

public ActionErrors validate(ActionMapping mapping,
HttpServletRequest request) {
ActionErrors errors=new ActionErrors();
if(userName==null || userName.length()<1){
errors.add("userName",new ActionMessage("name.error"));
}else if(password==null || password.length()<1){
errors.add("password",new ActionMessage("password.error"));
}
return errors;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}

public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}

Answer 1

错误信息的最后三行：
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:454)
at java.lang.Thread.run(Thread.java:619)login.jsp<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%@ taglib uri="http://struts.apache.org/tags-bean" prefix="bean" %>   
<%@ taglib uri="http://struts.apache.org/tags-html" prefix="html" %>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%><!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>" />
    
    <title>test</title>
    
<meta http-equiv="pragma" content="no-cache" />
<meta http-equiv="cache-control" content="no-cache" />
<meta http-equiv="expires" content="0" />    
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3" />
<meta http-equiv="description" content="This is my page" />
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->  </head>
  
  <body>
     <form action="<%=path%>/login.do">
     <bean:message key="jsp.userName" />：<input type="text" name="userName" />
     <html:errors property="name.error"/><br/>
     密  　码：
     <input type="password" name="password"/><br />
     <html:errors property="password.error"/><br />
     <input type="submit" />
     <input type="reset"/>
     </form>
  </body>
</html>当点击登陆的时候就报错！

Answer 2

 <form action="<%=path%>/login.do">
改为 <form action="<%=path%>/login.do" name="LoginForm">
试试

Answer 3

jsp里面的form你用的是html的,改成
<html:form action="/login">
   <bean:message key="jsp.userName" />：<html:text property="userName" />
   <html:errors property="name.error"/><br/>
   密  　码：
    <html:password property="password"/><br />
            <html:errors property="password.error"/><br />
            <input type="submit" />
            <input type="reset"/>
</html>你jsp里面既有struts的标签又有普通html的标签，很混乱。提交和reset按钮也就罢了,关键用户名和密码两个文本框也用的是html的那一套，这样就算你把form提交到了action,但是在进行ActionForm造型到你的LoginForm的时候,这个Form所有的成员都是null 的,你去equals比较,不报NullPointerException才怪。

Answer 4

呵呵，  搞错了， 不好意思， 我把 com.zxl.test.form  写成 com.zxl.test.from 了， 我改成3楼的报错了才知道。