JavaWeb三层架构

MVC

 

JavaWeb三层架构

案例：三层的HelloWorld程序

　　

　　User.java

U 
package cn.cmlx.user;

//把数据库查询出的数据保存到这个对象中
public class User {
    private String username;
    private String password;
    public User() {
        super();
        // TODO Auto-generated constructor stub
    }
    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 User(String username, String password) {
        super();
        this.username = username;
        this.password = password;
    }
    @Override
    public String toString() {
        return "User [username=" + username + ", password=" + password + "]";
    }

}
ser.java

　　UserDao.java

package cn.cmlx.userdao;

import cn.cmlx.user.User;

public class UserDao {
    //把xml中的数据查询出来之后，封装到user对象中，然后返回
    public User find() {
        return new User("赤名莉香","0218");
    }
}
UserDao.java

　　UserService.java

package cn.cmlx.service;

import cn.cmlx.user.User;
import cn.cmlx.userdao.UserDao;

public class UserService {
    //service层依赖dao层
    private UserDao userDao = new UserDao();
    //service的查询，需要使用dao来完成！
    public User find() {
        return userDao.find();
    }
}
UserService.java

　　UserServlet.java

package cn.cmlx.web.servlet;

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 cn.cmlx.service.UserService;
import cn.cmlx.user.User;

@WebServlet("/UserServlet")
public class UserServlet extends HttpServlet {

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        //在servlet中依赖service，然后通过service完成功能，把结果保存到request中
        //转发到jsp中显示
        UserService userService = new UserService();
        User user = userService.find();
        request.setAttribute("user", user);
        request.getRequestDispatcher("/sanceng/Show.jsp").forward(request, response);
    }

}
UserServlet.java

　　index.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>Insert title here</title>
</head>
<body>
<a href='<c:url value='/UserServlet'/>'>点击查看信息</a>
</body>
</html>
index.jsp

　　Show.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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>Insert title here</title>
</head>
<body>
用户名：${user.username }<br>
密　码：${user.password }<br>
</body>
</html>
Show.jsp

 

posted @ 2018-08-09 19:13  cmlx  阅读(151)  评论(0)    收藏  举报