MVC模式在Java Web应用程序中的实例分析

MVC实例应用模式

完成：MVC模式在Java Web应用程序中的实例分析

结合六个基本质量属性

分析具体功能模块的MVC设计实现（例如登录、用户权限等功能模块）

在实际项目中的具体应用

或分析MVC设计模式在具体网站中的应用（需要列举实例）

首先了解一下MVC框架是什么

模型-视图-控制器（MVC）是一个众所周知的以设计界面应用程序为基础的。它主要通过分离模型、视图及控制器在应用程序中的角色将业务逻辑从界面中解耦。通常，模型负责封装应用程序数据在视图层展示。视图仅仅只是展示这些数据，不包含任何业务逻辑。控制器负责接收来自用户的请求，并调用后台服务（manager或者dao）来处理业务逻辑。处理后，后台业务层可能会返回了一些数据在视图层展示。控制器收集这些数据及准备模型在视图层展示。MVC模式的核心思想是将业务逻辑从界面中分离出来，允许它们单独改变而不会相互影响。

 

 

以下介绍MVC实例

Controller部分

LoginController.java

package com.flf.controller;

import java.util.Date;
import java.util.List;

import javax.servlet.http.HttpSession;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.servlet.ModelAndView;

import com.flf.entity.Menu;
import com.flf.entity.Role;
import com.flf.entity.User;
import com.flf.service.MenuService;
import com.flf.service.UserService;
import com.flf.util.Const;
import com.flf.util.RightsHelper;
import com.flf.util.Tools;

@Controller
public class LoginController {

	@Autowired
	private UserService userService;
	@Autowired
	private MenuService menuService;
	
	/**
	 * 访问登录页
	 * @return
	 */
	@RequestMapping(value="/login",method=RequestMethod.GET)
	public String loginGet(){
		return "login";
	}
	
	/**
	 * 请求登录，验证用户
	 * @param session
	 * @param loginname
	 * @param password
	 * @param code
	 * @return
	 */
	@RequestMapping(value="/login",method=RequestMethod.POST)
	public ModelAndView loginPost(HttpSession session,@RequestParam String loginname,@RequestParam String password,@RequestParam String code){
		String sessionCode = (String)session.getAttribute(Const.SESSION_SECURITY_CODE);
		ModelAndView mv = new ModelAndView();
		String errInfo = "";
		if(Tools.notEmpty(sessionCode) && sessionCode.equalsIgnoreCase(code)){
			User user = userService.getUserByNameAndPwd(loginname, password);
			if(user!=null){
				user.setLastLogin(new Date());
				userService.updateLastLogin(user);
				session.setAttribute(Const.SESSION_USER, user);
				session.removeAttribute(Const.SESSION_SECURITY_CODE);
			}else{
				errInfo = "用户名或密码有误！";
			}
		}else{
			errInfo = "验证码输入有误！";
		}
		if(Tools.isEmpty(errInfo)){
			mv.setViewName("redirect:index.html");
		}else{
			mv.addObject("errInfo", errInfo);
			mv.addObject("loginname",loginname);
			mv.addObject("password",password);
			mv.setViewName("login");
		}
		return mv;
	}
	
	/**
	 * 访问系统首页
	 * @param session
	 * @param model
	 * @return
	 */
	@RequestMapping(value="/index")
	public String index(HttpSession session,Model model){
		User user = (User)session.getAttribute(Const.SESSION_USER);
		user = userService.getUserAndRoleById(user.getUserId());
		Role role = user.getRole();
		String roleRights = role!=null ? role.getRights() : "";
		String userRights = user.getRights();
		//避免每次拦截用户操作时查询数据库，以下将用户所属角色权限、用户权限限都存入session
		session.setAttribute(Const.SESSION_ROLE_RIGHTS, roleRights); //将角色权限存入session
		session.setAttribute(Const.SESSION_USER_RIGHTS, userRights); //将用户权限存入session
		
		List<Menu> menuList = menuService.listAllMenu();
		if(Tools.notEmpty(userRights) || Tools.notEmpty(roleRights)){
			for(Menu menu : menuList){
				menu.setHasMenu(RightsHelper.testRights(userRights, menu.getMenuId()) || RightsHelper.testRights(roleRights, menu.getMenuId()));
				if(menu.isHasMenu()){
					List<Menu> subMenuList = menu.getSubMenu();
					for(Menu sub : subMenuList){
						sub.setHasMenu(RightsHelper.testRights(userRights, sub.getMenuId()) || RightsHelper.testRights(roleRights, sub.getMenuId()));
					}
				}
			}
		}
		model.addAttribute("user", user);
		model.addAttribute("menuList", menuList);
		return "index";
	}
	
	/**
	 * 进入首页后的默认页面
	 * @return
	 */
	@RequestMapping(value="/default")
	public String defaultPage(){
		return "default";
	}
	
	/**
	 * 用户注销
	 * @param session
	 * @return
	 */
	@RequestMapping(value="/logout")
	public String logout(HttpSession session){
		session.removeAttribute(Const.SESSION_USER);
		session.removeAttribute(Const.SESSION_ROLE_RIGHTS);
		session.removeAttribute(Const.SESSION_USER_RIGHTS);
		return "login";
	}
}

View部分

Login.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>XXX管理系统</title>
<style type="text/css">
	body{margin-left: 0px;margin-top: 0px;margin-right: 0px;margin-bottom: 0px;background-color: #1B3142;}
	.header{100%;height:41px;background: url(images/login-top-bg.gif) repeat-x;}
	.center{100%;height:532px;background: url(images/login_bg.jpg) repeat-x;}
	.login_right{float:right;50%;height:100%;background: url(images/login-wel.gif) bottom no-repeat;}
	.login_left{float:right;295px;height:100%;background: url(images/login-content-bg.gif) no-repeat;}
	.login_title{margin-left:35px;font-family: Arial, Helvetica, sans-serif;font-size: 14px;height:36px;line-height: 36px;color: #666666;font-weight: bold;}
	.login_info{margin-left:35px;font-family: Arial, Helvetica, sans-serif;font-size: 12px;height:36px;line-height: 36px;color: #333333;}
	.login_input{150px;height:20px;margin-left:30px;border:1px solid #7F9DB9;vertical-align: middle;}
	.login_code{70px;height:20px;margin-left:30px;border:1px solid #7F9DB9;vertical-align: middle;}
	.btn{60px;height:25px;border-0px;background-image: url(images/btn-bg2.gif);letter-spacing: 3px;margin-right:70px;cursor: pointer;}
	.login_info img{vertical-align: middle;cursor: pointer;}
	
	.errInfo{display:none;color:red;}
	
	.logo{100%;height:68px;background: url(images/logo2.png) no-repeat;_background:none;_filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(src='images/logo2.png';)}
	.left_txt{font-family: Arial, Helvetica, sans-serif;font-size: 12px;line-height: 25px;color: #666666;}
	
	.bottom{100%;height:auto;text-align:center;font-family: Arial, Helvetica, sans-serif;font-size: 10px;color: #ABCAD3;text-decoration: none;line-height: 20px;}
</style>
<script type="text/javascript" src="js/jquery-1.5.1.min.js"></script>
</head>
<body>
<div style="100%;height:645px;position: absolute;top:50%;left:50%;margin-top:-320px;margin-left:-50%;">
	<div class="header"></div>
	<div class="center">
		<div class="login_right">
			<div style="100%;height:auto;margin-top:150px;">
			<form action="login.html" method="post" name="loginForm" onsubmit="check();">
				<div class="login_title">
					管理员登录
				</div>
				<div class="login_info">
					<label>用户名：</label><input type="text" name="loginname" id="loginname" class="login_input" value="${loginname }"/>
					 <span id="nameerr" class="errInfo"></span>
				</div>
				<div class="login_info">
					<label>密　码：</label><input type="password" name="password" id="password" class="login_input" value="${password }"/>
					 <span id="pwderr" class="errInfo"></span>
				</div>
				<div class="login_info">
					<label>验证码：</label><input type="text" name="code" id="code" class="login_code"/>  
					<img id="codeImg" alt="点击更换" title="点击更换" src=""/>
					 <span id="codeerr" class="errInfo"></span>
				</div>
				<div class="login_info">
					<input type="submit" name="loginBtn" value="登录" class="btn"/>
					<input type="reset" name="cancelBtn" value="取消" class="btn"/>
				</div>
			</form>
			</div>
		</div>
		<div class="login_left">
			<div style="100%;height:auto;margin-top:150px;">
				<div class="logo"></div>
				<div class="left_txt">
				
				</div>
			</div>
		</div>
	</div>
	<div class="bottom">
	
	</div>
</div>
	<script type="text/javascript">
		var errInfo = "${errInfo}";
		$(document).ready(function(){
			changeCode();
			$("#codeImg").bind("click",changeCode);
			if(errInfo!=""){
				if(errInfo.indexOf("验证码")>-1){
					$("#codeerr").show();
					$("#codeerr").html(errInfo);
					$("#code").focus();
				}else{
					$("#nameerr").show();
					$("#nameerr").html(errInfo);
				}
			}
			$("#loginname").focus();
		});
	
		function genTimestamp(){
			var time = new Date();
			return time.getTime();
		}
	
		function changeCode(){
			$("#codeImg").attr("src","code.html?t="+genTimestamp());
		}
		
		function resetErr(){
			$("#nameerr").hide();
			$("#nameerr").html("");
			$("#pwderr").hide();
			$("#pwderr").html("");
			$("#codeerr").hide();
			$("#codeerr").html("");
		}
		
		function check(){
			resetErr();
			if($("#loginname").val()==""){
				$("#nameerr").show();
				$("#nameerr").html("用户名不得为空！");
				$("#loginname").focus();
				return false;
			}
			if($("#password").val()==""){
				$("#pwderr").show();
				$("#pwderr").html("密码不得为空！");
				$("#password").focus();
				return false;
			}
			if($("#code").val()==""){
				$("#codeerr").show();
				$("#codeerr").html("验证码不得为空！");
				$("#code").focus();
				return false;
			}
			return true;
		}
	</script>
</body>
</html>

 Model

 

user.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 
	"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.flf.mapper.UserMapper">
	<sql id="userColumns">loginname,username,password,rights,status,role_id</sql>

	<resultMap type="User" id="userAndRoleResultMap">
		<id column="user_id" property="userId"/>
		<result column="loginname" property="loginname"/>
		<result column="username" property="username"/>
		<result column="password" property="password"/>
		<result column="user_rights" property="rights"/>
		<result column="status" property="status"/>
		<result column="last_login" property="lastLogin"/>
		<association property="role" column="role_id" javaType="Role">
			<id column="role_id" property="roleId"/>
			<result column="role_name" property="roleName"/>
			<result column="role_rights" property="rights"/>
		</association>
	</resultMap>
	<resultMap type="User" id="userResultMap">
		<id column="user_id" property="userId"/>
		<result column="loginname" property="loginname"/>
		<result column="username" property="username"/>
		<result column="password" property="password"/>
		<result column="rights" property="rights"/>
		<result column="status" property="status"/>
		<result column="role_id" property="roleId"/>
	</resultMap>
	
	<select id="listAllUser" resultMap="userAndRoleResultMap">
		select u.user_id,u.username,u.loginname,u.password,r.role_id,r.role_name ,u.last_login
		from tb_user u 
		left join tb_role r on u.role_id=r.role_id 
		where u.status=0 
	</select>
	
	<select id="listPageUser" parameterType="User" resultMap="userAndRoleResultMap">
		select u.user_id,u.username,u.loginname,u.password,r.role_id,r.role_name ,u.last_login
		from tb_user u 
		left join tb_role r on u.role_id=r.role_id 
		where u.status=0 
		<if test="loginname!=null and loginname!=''">
			and u.loginname like "%"#{loginname}"%" 
		</if>
		<if test="roleId!=null and roleId!=0">
			and u.role_id=#{roleId} 
		</if>
		<if test="lastLoginStart!=null">
		and u.last_login>=#{lastLoginStart} 
		</if>
		<if test="lastLoginEnd!=null">
		and u.last_login<=#{lastLoginEnd} 
		</if>
	</select>
	
	<select id="getUserInfo" parameterType="User" resultMap="userResultMap">
		select * from tb_user where 1=1
		<if test="loginname!=null and password!=null">
		and loginname = #{loginname} and password=#{password}
		</if>
		<if test="userId!=null and userId>0">
		and user_id = #{userId}
		</if>
	</select>
	<select id="getUserById" parameterType="int" resultMap="userResultMap">
		select * from tb_user u where u.user_id = #{userId}
	</select>
	<select id="getUserAndRoleById" parameterType="int" resultMap="userAndRoleResultMap">
		select u.user_id,u.username,u.rights as user_rights,u.loginname,u.password,r.role_id,r.role_name,r.rights as role_rights 
		from tb_user u 
		left join tb_role r on u.role_id=r.role_id 
		where u.status=0 and u.user_id=#{userId}
	</select>
	<select id="getCountByName" parameterType="User" resultType="int">
		select count(user_id) from tb_user where loginname=#{loginname}
	</select>
	<select id="getCount" parameterType="User" resultType="int">
		select count(user_id) from tb_user where status=0 
		<if test="loginname!=null and loginname!=''">
		 and loginname like "%"#{loginname}"%" 
		</if>
		<if test="roleId!=null and roleId!=0">
		and role_id=#{roleId} 
		</if>
		<if test="lastLoginStart!=null">
		and last_login>=#{lastLoginStart} 
		</if>
		<if test="lastLoginEnd!=null">
		and last_login<=#{lastLoginEnd} 
		</if>
	</select>
	
	<insert id="insertUser" parameterType="User" useGeneratedKeys="true" keyProperty="userId">
		insert tb_user (<include refid="userColumns"/>) values (#{loginname},#{username},#{password},#{rights},0,#{roleId})
	</insert>
	<update id="updateUser" parameterType="User">
		update tb_user set 
		loginname=#{loginname},
		username=#{username},password=#{password},
		rights=#{rights},
		status=#{status},
		role_id=#{roleId},
		last_login=#{lastLogin} 
		where user_id=#{userId}
	</update>
	<update id="updateLastLogin" parameterType="User">
		update tb_user set last_login=#{lastLogin} where user_id=#{userId}
	</update>
	<update id="updateUserBaseInfo" parameterType="User">
		update tb_user set 
		loginname=#{loginname},
		username=#{username},
		role_id=#{roleId} 
		<if test="password!=null and password!=''">,password=#{password} </if>
		 where user_id=#{userId}
	</update>
	<update id="updateUserRights" parameterType="User">
		update tb_user set rights=#{rights} where user_id=#{userId}
	</update>
	<delete id="deleteUser" parameterType="int">
		delete from tb_user where user_id=#{userId}
	</delete>
</mapper>

 在本实例中，还通过MyExceptionResolver.java检测异常，提高了系统的可用性，代码如下

package com.flf.resolver;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;
//可用性
public class MyExceptionResolver implements HandlerExceptionResolver{

	public ModelAndView resolveException(HttpServletRequest request,
			HttpServletResponse response, Object handler, Exception ex) {
		// TODO Auto-generated method stub
		System.out.println("==============异常开始=============");
		ex.printStackTrace();
		System.out.println("==============异常结束=============");
		ModelAndView mv = new ModelAndView("error");
		mv.addObject("exception", ex.toString().replaceAll("
", "<br/>"));
		return mv;
	}

}

与此同时通过登录的权限控制提高了系统的安全性