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<String , User> userMap = new HashMap<String , User>();
public static List<Goods> goodsList = new ArrayList<Goods>();
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<Goods> list = new GoodsService().selectAllGoods();
request.setAttribute("list", list);
request.getRequestDispatcher("/admin/goods_list.jsp").forward(request, response);
}
}
GoodsListServlet.java
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", "<font color=‘red‘>用户名或密码错误，请重新登录！</font>");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}
}
}
LoginServlet.java
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", "<font color=‘green‘>注册成功，请登录！</font>");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}else {
request.setAttribute("msg", "<font color=‘red‘>用户名重复，请重新填写</font>");
request.getRequestDispatcher("/register.jsp").forward(request, response);
}
}
}
RegisterService.java
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<Goods> getAllGoods(){
return DBUtil.goodsList;
}
}
GoodsDao.java
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;
}
}
UserDao.java
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;
}
}
Goods.java
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;
}
}
User.java
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<Goods> selectAllGoods(){
return new GoodsDao().getAllGoods();
}
}
GoodsService.java
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);
}
}
UserService.java
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<String , User> userMap = new HashMap<String , User>();
public static List<Goods> goodsList = new ArrayList<Goods>();
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);
}
}
DBUtil.java
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"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
<style type="text/css">
*{
font-size = 20px;
}
</style>
</head>
<body>
<h1>商品管理</h1>
</hr>
<a>添加</a>
<table border = "1">
<tr>
<td>商品名</td><td>描述</td><td>价格</td><td>库存</td><td>操作</td>
</tr>
<%
List<Goods> list = (List<Goods>)request.getAttribute("list");
for(Goods goods : list){
%>
<tr>
<td><%=goods.getName() %></td><td><%=goods.getDes() %></td><td><%=goods.getPrice() %></td><td><%=goods.getInventory() %></td><td>删除 修改</td>
</tr>
<%
}
%>
<!-- <tr> -->
<!-- <td>香蕉</td><td>这个是香蕉</td><td>78</td><td>500</td><td>删除 修改</td> -->
<!-- </tr> -->
</body>
</html>
goods_list.jsp
首页面
<%@ page import="com.Gary.model.User" %>
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<%
Object user = session.getAttribute("user");
if(user==null){
%>
<a href="<%=request.getContextPath() %>/login.jsp">登录</a>
<a href="<%=request.getContextPath() %>/register.jsp">注册</a>
<%
}else{
out.println("当前登录用户："+((User)user).getUsername());
}
%>
<body>
</br>
各种商品的展示
</body>
</html>
index.jsp
用户登录页面
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<%
if(request.getAttribute("msg")!=null)
out.println(request.getAttribute("msg")+"<br/>");
%>
登录
<hr/>
<form action="<%=request.getContextPath() %>/login_do" method="post">
用户名：<input type="text" name="username" /><br/>
密码：<input type="password" name="password" /><br/>
<input type="submit" value="登录" />
</form>
</body>
</html>
login.jsp
用户注册页面
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Insert title here</title>
</head>
<body>
<%
if(request.getAttribute("msg")!=null)
out.println(request.getAttribute("msg")+"<br/>");
%>
注册
<hr/>
<form action="<%=request.getContextPath() %>/register_do" method="post">
用户名：<input type="text" name="username" /><br/>
密码：<input type="password" name="password" /><br/>
年龄：<input type="text" name="age" /><br/>
性别： 男<input type="radio" name="sex" value="男" checked="checked"/>女<input type="radio" name="sex" value="女" /><br/>
<input type="submit" value="注册" />
</form>
</body>
</html>
register.jsp
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){
%>
<a href="<%=request.getContextPath() %>/login.jsp">登录</a>
<a href="<%=request.getContextPath() %>/register.jsp">注册</a>
<%
}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
<form action="<%=request.getContextPath() %>/register_do" method="post"> 用户名：<input type="text" name="username" /><br/> 密码：<input type="password" name="password" /><br/> 年龄：<input type="text" name="age" /><br/> 性别： 男<input type="radio" name="sex" value="男" checked="checked"/>女<input type="radio" name="sex" value="女" /><br/> <input type="submit" value="注册" /> </form>
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<String , User> userMap = new HashMap<String , User>();
public static List<Goods> goodsList = new ArrayList<Goods>();
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<Goods> 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", "<font color=‘green‘>注册成功，请登录！</font>");
request.getRequestDispatcher("/login.jsp").forward(request, response);
}else {
request.setAttribute("msg", "<font color=‘red‘>用户名重复，请重新填写</font>");
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<Goods> 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<Goods> list = (List<Goods>)request.getAttribute("list");
for(Goods goods : list){
%>
<tr>
<td><%=goods.getName() %></td><td><%=goods.getDes() %></td><td><%=goods.getPrice() %></td><td><%=goods.getInventory() %></td><td>删除 修改</td>
</tr>
<%
}
%>
<!-- <tr> -->
<!-- <td>香蕉</td><td>这个是香蕉</td><td>78</td><td>500</td><td>删除 修改</td> -->
<!-- </tr> -->
原文地址：https://www.cnblogs.com/1138720556Gary/p/10308338.html
时间： 2024-08-26 15:14:10