菜鸟紧急求助 初学struts 找不出错误
struts-config.xml
<?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="com.pdsu.cbx.LoginForm "></form-bean>
   </form-beans>
   <action-mappings >
   <action path="/login" type="com.pdsu.cbx.LoginAction" name="loginForm">
   <forward name="loginSucess" path="/welcome.jsp"></forward>
   <forward name="loginFailure" path="/login.jsp"></forward>
   </action>
   </action-mappings>
   <message-resources parameter="com.yourcompany.struts.ApplicationResources" />
</struts-config>
LoginAction.java
package com.pdsu.cbx;
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;
public class LoginAction extends Action {
	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {		
		LoginForm  loginForm=(LoginForm) form;				
		if(loginForm.getUsername().equals("admin")&&loginForm.getPassword().equals("123")){
			return mapping.findForward("loginSucess");
		}
		else{
			return mapping.findForward("loginFailure");
		}							
	}
}
LoginForm.java
package com.pdsu.cbx;
import org.apache.struts.action.ActionForm;
public class LoginForm extends ActionForm {
private String username;
private String password;
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;
}
}
login.jsp
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<html>
   <head>           
     <title>My JSP 'login.jsp' starting page</title>	
   </head>    
   <body>
   <form action="login.do" method="post">
   username:<input type="text" name="username" ><br>
   password:<input type="password" name="password"/><br>
   <input type="submit" value="login"/>
   </form>
   </body>
</html>
错误提示
HTTP Status 500 -  
--------------------------------------------
type Exception report
message  
description 
The server encountered an internal error () that prevented it from fulfilling this req