JSP之错误信息提示

MessageResource.properties配置文件：

RegisterAction注册：

package com.caiduping.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 cn.itcast.web.formbean.UserFormbean;

public class RegisterAction extends Action {

	//actionServlet
	@Override
	public ActionForward execute(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {	
		String param = mapping.getParameter();
		System.out.println(param);
		UserFormbean bean = (UserFormbean) request.getSession().getAttribute("UserFormBean");
		System.out.println(bean.getUsername());
		System.out.println(bean.getPassword());
		System.out.println(bean.getEmail());
		try{
			System.out.println("向数据注册用户！！");
			request.setAttribute("message", "注册成功");
		}catch (Exception e) {
			request.setAttribute("message", "注册失败");
		}
		
		return mapping.findForward("message");
	}

	
	
}

UserFormbean表格：

package com.caiduping.formbean;

import java.util.ResourceBundle;

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;
import org.apache.struts.util.MessageResources;


//actionServlet
public class UserFormbean extends ActionForm {

	private String username;
	private String password;
	private String email;
	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;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	//actionServlet
	@Override
	public ActionErrors validate(ActionMapping mapping,
			HttpServletRequest request) {
		
		ActionErrors errors = new ActionErrors();
		if(this.username==null || this.username.trim().equals("")){
			errors.add("username", new ActionMessage("用户名不能为空",false));
			errors.add("username", new ActionMessage("errors.username.required"));	
			errors.add("username", new ActionMessage("errors.required","用户名"));	
			MessageResources mr = MessageResources.getMessageResources("cn.itcast.resource.MessageResource");
			errors.add("username", new ActionMessage("errors.required",mr.getMessage("prompt.username")));
		}
		return errors;
	}
	
	
	
}

页面不存在404.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>My JSP '404.jsp' starting page</title>
  </head>
  
  <body>
    对不起，您要访问资源不存在
  </body>
</html>

index.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<%@taglib uri="http://struts.apache.org/tags-html" prefix="html" %>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>My JSP 'index.jsp' starting page</title>
  </head>
  
  <body>
   	<a href="${pageContext.request.contextPath }/RegisterUI.do">注册</a>
   	
   	<c:url var="register" value="/RegisterUI.do"/>
   	<a href="${register }">注册</a>
   	
   	
   	<% 
   		request.setAttribute("name","中国");
   	%>
   	<html:link action="/RegisterUI" paramId="name" paramName="name">注册</html:link>
   	
   	
   	<% 
   		Map map = new HashMap();
   		map.put("aa","1");
   		map.put("bb","2");
   		map.put("cc","3");
   		
   		request.setAttribute("map",map);
   	%>
   	
   	<html:link action="/RegisterUI" name="map">注册</html:link>
   	
   	<% 
   		request.setAttribute("now",new Date());
   	%>
   	<html:link action="/RegisterUI" paramId="now" paramName="now" paramProperty="time">注册</html:link>
   	
  </body>
</html>

传递消息message.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>


<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <title>My JSP 'message.jsp' starting page</title>
  </head>
  
  <body>
    ${message }
  </body>
</html>

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>ActionServlet</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>ActionServlet</servlet-name>
  	<url-pattern>*.do</url-pattern>
  </servlet-mapping>
  

  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

run:

不努力，还要青春干什么？