MVC分层实现管理员后台商品查询

 

　　MVC层即model view controller

　　Model(模型)：模型代表着核心的业务逻辑和数据（不要理解成Model只是实体类）

　　View（视图）：视图应该关注与如何展示数据，而不应该包含任何业务逻辑（业务逻辑应写在Model中）

　　Controller（控制器）：控制器控制着程序的逻辑，并充当着视图和模型之间的协调角色。控制器从视图层接收用户输入的信息，然后使用模型来执行特定的操作，并把最终的结果回传给视图

　　model层：存放业务逻辑处理，不直接和数据库打交道但存放关于数据库处理的操作

　　Dao层：对数据库进行数据持久化操作，操作直接针对数据库

 

　　index.jsp进行首页的展示，用户可以在首页进行普通用户的注册和登录，当使用管理员账号登录时候可以进入商品后台对其进行进一步管理(LoginServlet.java中实现)

　　项目结构

　　

 

　　DBUtil.java模拟数据库，已存在的管理员用户和商品信息列表如下，注册时只能对普通用户进行注册，Gary和Gary2的isAdmin为True

public static Map
     
       userMap = new HashMap
      
       ();    public static List
       
         goodsList = new ArrayList
        
         ();        static {        addUser(new User("Gary","123",10,"男",true));        addUser(new User("Gary2","456",20,"男",true));                goodsList.add(new Goods("香蕉","这个是香蕉",100,110));        goodsList.add(new Goods("苹果","这个是苹果",200,120));        goodsList.add(new Goods("西瓜","这个是西瓜",300,130));        goodsList.add(new Goods("桃子","这个是桃子",400,140));    }
        
       
      
     

 

 

逻辑层：处理代码请求

package com.Gary.controller;import java.io.IOException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.Gary.model.Goods;import com.Gary.service.GoodsService;@WebServlet("/admin/goods_list")public class GoodsListServlet extends HttpServlet {        @Override    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {            doGet(req, resp);    }        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        List
      
        list = new GoodsService().selectAllGoods();        request.setAttribute("list", list);        request.getRequestDispatcher("/admin/goods_list.jsp").forward(request, response);    }}
      

 

package com.Gary.controller;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.Gary.model.User;import com.Gary.service.UserService;@WebServlet("/login_do")public class LoginServlet extends HttpServlet {    @Override    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        String username = request.getParameter("username");        String password = request.getParameter("password");                UserService service = new UserService();        User user =service.login(username, password);                System.out.println(user);        if(user!=null) {            request.getSession().setAttribute("user", user);            //System.out.println(user);            //TODO            if(user.isAdmin()) {                //管理员                //response.sendRedirect(request.getContextPath()+"/admin/goods_list.jsp");                request.getRequestDispatcher("admin/goods_list").forward(request, response);                //不需要传递数据时可以使用重定向                //response.sendRedirect(request.getContextPath()+"/admin/good_list");            }else {                //普通用户                //System.out.println("完成");                request.getRequestDispatcher("/").forward(request, response);            }        }else {            request.setAttribute("msg", "用户名或密码错误，请重新登录！");            request.getRequestDispatcher("/login.jsp").forward(request, response);        }    }}

 

package com.Gary.controller;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.Gary.service.UserService;/** * Servlet implementation class RegisterService */@WebServlet("/register_do")public class RegisterService extends HttpServlet {        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        //设置中文编码        request.setCharacterEncoding("utf-8");        String username = request.getParameter("username");        String password = request.getParameter("password");        int age = Integer.parseInt(request.getParameter("age"));        String sex = request.getParameter("sex");                UserService  userService = new UserService();        boolean isSuccess = userService.register(username,password,age,sex);        if(isSuccess) {            request.setAttribute("msg", "注册成功，请登录！");            request.getRequestDispatcher("/login.jsp").forward(request, response);        }else {            request.setAttribute("msg", "用户名重复，请重新填写");            request.getRequestDispatcher("/register.jsp").forward(request, response);        }    }}

 

DAO层：将数据存到数据库中

package com.Gary.dao;import java.util.List;import com.Gary.model.Goods;import com.Gary.util.DBUtil;public class GoodsDao {    public    List
      
        getAllGoods(){        return DBUtil.goodsList;    }}
      

 

package com.Gary.dao;import com.Gary.model.User;import com.Gary.util.DBUtil;public class UserDao {        public boolean isExist(String username) {        return DBUtil.userMap.containsKey(username);    }        public boolean addUser(String username,String password,int age,String sex) {        if(isExist(username))    return false;        User u = new User(username,password,age,sex,false);        DBUtil.userMap.put(u.getUsername(),u);        return true;    }        public User getUserByUP(String username,String password) {        if(isExist(username)==false)     return null;        User u = DBUtil.userMap.get(username);        if(u.getPassword().equals(password))return u;        else    return null;    }        }

 

model层：存放我们的实体类，与数据库中的属性值基本保持一致

package com.Gary.model;public class Goods {    private String name;    private String des;    private int price;    private int inventory;    public Goods(String name, String des, int price, int inventory) {        super();        this.name = name;        this.des = des;        this.price = price;        this.inventory = inventory;    }        public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getDes() {        return des;    }    public void setDes(String des) {        this.des = des;    }    public int getPrice() {        return price;    }    public void setPrice(int price) {        this.price = price;    }    public int getInventory() {        return inventory;    }    public void setInventory(int inventory) {        this.inventory = inventory;    }    }

 

package com.Gary.model;public class User {    private String username;    private String password;    private int age;    private String sex;    private boolean isAdmin=false;    //判断是否是管理员账号        public User(String username, String password, int age, String sex, boolean isAdmin) {        super();        this.username = username;        this.password = password;        this.age = age;        this.sex = sex;        this.isAdmin = isAdmin;    }    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 int getAge() {        return age;    }    public void setAge(int age) {        this.age = age;    }    public String getSex() {        return sex;    }    public void setSex(String sex) {        this.sex = sex;    }    public boolean isAdmin() {        return isAdmin;    }    public void setAdmin(boolean isAdmin) {        this.isAdmin = isAdmin;    }    }

 

service层：存放业务逻辑处理

package com.Gary.service;import java.util.List;import com.Gary.dao.GoodsDao;import com.Gary.model.Goods;public class GoodsService {    public List
      
        selectAllGoods(){        return new GoodsDao().getAllGoods();    }}
      

 

package com.Gary.service;import com.Gary.dao.UserDao;import com.Gary.model.User;public class UserService {    //处理注册请求    public boolean register(String username,String password,int age ,String sex) {        UserDao userDao = new UserDao();        boolean isExist =userDao.isExist(username);        if(isExist)                return false;        else             userDao.addUser(username, password, age, sex);        return true;    }        public User login(String username,String password) {        return new UserDao().getUserByUP(username, password);    }}

 

util层：辅助作用　　【我用来做数据库的模拟】

package com.Gary.util;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import com.Gary.model.Goods;import com.Gary.model.User;//模拟数据库public class DBUtil {    public static Map
      
        userMap = new HashMap
       
        ();    public static List
        
          goodsList = new ArrayList
         
          ();        static {        addUser(new User("Gary","123",10,"男",true));        addUser(new User("Gary2","456",20,"男",true));                goodsList.add(new Goods("香蕉","这个是香蕉",100,110));        goodsList.add(new Goods("苹果","这个是苹果",200,120));        goodsList.add(new Goods("西瓜","这个是西瓜",300,130));        goodsList.add(new Goods("桃子","这个是桃子",400,140));    }        private static void addUser(User user) {        userMap.put(user.getUsername(), user);    }    }
         
        
       
      

 

商品列表页面

<%@page import="com.Gary.model.Goods"%><%@page import="java.util.List"%><%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%>
      
商品管理
添加
      
        list = (List
       
        )request.getAttribute("list");for(Goods goods : list){    %>    
       
      
      
<%List
    <%}%>
       
        
         
商品名
         
描述
         
价格
         
库存
         
操作
        
        
                 
<%=goods.getName() %>
         
<%=goods.getDes() %>
         
<%=goods.getPrice() %>
         
<%=goods.getInventory() %>
         
删除 修改
            
                               
      

 

首页面

<%@ page import="com.Gary.model.User" %><%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%>
      <%Object user = session.getAttribute("user");if(user==null){    %>    登录    注册    <%         }else{    out.println("当前登录用户："+((User)user).getUsername());}%>
各种商品的展示

 

用户登录页面

<%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%>
      <%if(request.getAttribute("msg")!=null)    out.println(request.getAttribute("msg")+"
");%>登录 
      
      
       用户名：
       
       
密码：
       
       
       
      

 

用户注册页面

<%@ page language="java" contentType="text/html; charset=utf-8"    pageEncoding="utf-8"%>
      <%if(request.getAttribute("msg")!=null)    out.println(request.getAttribute("msg")+"
");%>注册
      
      
       用户名：
       
       
密码：
       
       
年龄：
       
       
性别： 男
       女
       
       
       
      

 

 

实现过程

　　index.jsp判断有无用户登录，有用户登录时展示用户信息，若无用户登录则显示用户注册登录

<%Object user = session.getAttribute("user");if(user==null){    %>    登录    注册    <%         }else{    out.println("当前登录用户："+((User)user).getUsername());}%>

 

　　用户注册后将表单提交给register_do

     
      用户名：
      
      
密码：
      
      
年龄：
      
      
性别： 男
      女
      
      
      
     

 

　　创建用户数据模型User,java和Goods.java

private String username;    private String password;    private int age;    private String sex;    private boolean isAdmin=false;    //判断是否是管理员账号

　　

private String name;    private String des;    //商品描述信息    private int price;    private int inventory;    //商品库存

 

　　DBUtil.java模拟数据库，将用户与商品存放到List<>集合中

public static Map
     
       userMap = new HashMap
      
       ();    public static List
       
         goodsList = new ArrayList
        
         ();        static {        addUser(new User("Gary","123",10,"男",true));        addUser(new User("Gary2","456",20,"男",true));                goodsList.add(new Goods("香蕉","这个是香蕉",100,110));        goodsList.add(new Goods("苹果","这个是苹果",200,120));        goodsList.add(new Goods("西瓜","这个是西瓜",300,130));        goodsList.add(new Goods("桃子","这个是桃子",400,140));    }        private static void addUser(User user) {        userMap.put(user.getUsername(), user);    }
        
       
      
     

 

　　UserDao.java和GoodDao.java处理数据库逻辑

//用户是否退出登录    public boolean isExist(String username) {        return DBUtil.userMap.containsKey(username);    }        //添加用户    public boolean addUser(String username,String password,int age,String sex) {        if(isExist(username))    return false;        User u = new User(username,password,age,sex,false);        DBUtil.userMap.put(u.getUsername(),u);        return true;    }        //判断用户是否登录成功    public User getUserByUP(String username,String password) {        if(isExist(username)==false)     return null;        User u = DBUtil.userMap.get(username);        if(u.getPassword().equals(password))return u;        else    return null;    }

 

public class GoodsDao {    //列出所有的商品    public    List
     
       getAllGoods(){        return DBUtil.goodsList;    }}
     

 

　　RegisterService.java处理用户注册信息，处理用户的注册和登录

@WebServlet("/register_do")public class RegisterService extends HttpServlet {        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        //设置中文编码        request.setCharacterEncoding("utf-8");        String username = request.getParameter("username");        String password = request.getParameter("password");        int age = Integer.parseInt(request.getParameter("age"));        String sex = request.getParameter("sex");                UserService  userService = new UserService();        boolean isSuccess = userService.register(username,password,age,sex);        if(isSuccess) {            request.setAttribute("msg", "注册成功，请登录！");            request.getRequestDispatcher("/login.jsp").forward(request, response);        }else {            request.setAttribute("msg", "用户名重复，请重新填写");            request.getRequestDispatcher("/register.jsp").forward(request, response);        }    }}

 

 　　LoginServlet.java处理用户登录后分用户和管理员操作，用户跳转到首页，管理员则转发到goods_list对商品后台信息进行处理

　　GoodsListServlet.java处理转发的goods_list请求

@WebServlet("/admin/goods_list")public class GoodsListServlet extends HttpServlet {        @Override    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {            doGet(req, resp);    }        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {        List
     
       list = new GoodsService().selectAllGoods();        request.setAttribute("list", list);        request.getRequestDispatcher("/admin/goods_list.jsp").forward(request, response);    }}
     

 

 　　goods_list.jsp展示数据库中商品信息列表

 

<%List
     
       list = (List
      
       )request.getAttribute("list");for(Goods goods : list){    %>            <%=goods.getName() %><%=goods.getDes() %><%=goods.getPrice() %><%=goods.getInventory() %>删除 修改        <%}%>