Spring实战 - 用户登录

Posted 2021-03-16 9Coding

• 环境： MacOS + IntelliJ IDEA 2019.3.1 (Ultimate Edition)

基于Java Web项目单体架构，创建登录模块。

• 开发顺序：
  1、 entity 实体类
  2、dao 数据访问层
  3、service 业务逻辑
  4、view 视图层

• 开发示例：
  1、在entity目录下创建实体类User

package com.coding.demo.entity;

/**
 * @author 码出高薪
 * @date 2020/1/8
 */
public class User {
  private String name;
  private String password;
  
  public User(String name,String password){
    this.name = name;
    this.password = password;
  }
  
  public void setName(String name){
    this.name = name;
  }
  public void setPassword(String password){
    this.password = password;
  }
  public String getName(){
    return this.name;
  }
  public String getPassword(){
    return this.password;
  }
  @Override
  public String toString() {
    return "User{" +
        "name=\'" + name + \'\\\'\' +
        ", password=\'" + password + \'\\\'\' +
        \'}\';
  }
}

2、在dao目录下创建IUserDao接口

package com.coding.demo.dao;
/**
 * 用户数据访问
 * @author 码出高薪
 * @date 2020/1/8
 */
public interface IUserDao {
  /**
   * 用户登录
   * @param name 用户名
   * @param password 密码
   * @return User 用户
   */
  public User login(String name,String password);
}

3、在dao目录下创建存放数据访问层接口实现类的文件夹

mkdir -p ~/Documents/test/demo/src/main/java/com/coding/demo/dao/impl

4、在impl文件夹创建UserDao接口的实现类UserDaoImpl

package com.coding.demo.dao.impl;
import com.coding.demo.dao.IUserDao;
import com.coding.demo.entity.User;
/**
 * 用户数据访问
 * @author 码出高薪
 * @date 2020/1/8
 */
public class UserDaoImpl implements IUserDao {
  // 已知用户名和密码
  private String username = "Jack";
  private String password = "1234";
  /**
   * 用户登录
   * @param username 用户名
   * @param password 密码
   * @return User 用户
   */

  public User login(String username, String password) {
    User user = null;
//    根据用户名查找用户信息
    if(this.username.equals(username)){
      if(this.password.equals(password)){
        user = new User();
        user.setUsername(username);
        user.setPassword(password);
      }
    }
    return user;
  }
}

5、在service目录下创建IUserLoginService接口

package com.coding.demo.service;
import com.coding.demo.entity.User;
/**
 * 处理登录业务逻辑
 * @author 码出高薪
 * @date 2020/1/8
 */
public interface IUserLoginService {

  /**
   * 登录
   * @param username 用户名
   * @param password 密码
   * @return User 用户
   */
  User login(String username, String password);
}

6、在service目录下创建存放业务逻辑层接口实现类的文件夹

mkdir -p ~/Documents/test/demo/src/main/java/com/coding/demo/service/impl

7、在impl文件夹创建IUserLoginService接口的实现类

package com.coding.demo.service;

import com.coding.demo.entity.User;

/**
 * 实现登录业务逻辑接口
 * @author 码出高薪
 * @date 2020/1/8
 */
public interface IUserLoginService {

  /**
   * 登录
   * @param username
   * @param password
   * @return
   */
  User login(String username, String password);
}

8、在web文件夹创建controller

mkdir -p ~/Documents/test/demo/src/main/java/com/coding/demo/web/controller

9、在controller 文件夹下创建UserLoginController

package com.coding.demo.web.controller;

import com.coding.demo.entity.User;
import com.coding.demo.service.IUserLoginService;
import com.coding.demo.service.impl.IUserLoginServiceImpl;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 登录控制器
 * @author 码出高薪
 * @date 2020/1/8
 */
public class UserLoginController extends HttpServlet {

  private IUserLoginService userService = new IUserLoginServiceImpl();
  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp)
      throws ServletException, IOException {
  }

  @Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp)
      throws ServletException, IOException {
    String username = req.getParameter("username");
    String password = req.getParameter("password");
    User user = userService.login(username, password);
//    登录失败处理
    if(user == null){
      req.getRequestDispatcher("/fail.jsp").forward(req,resp);
    }
//    登录成功处理
    else {
      req.getRequestDispatcher("/success.jsp").forward(req,resp);
    }
  }
}

10、创建WEB-INF

mkdir -p /Users/liujia/Documents/test/demo/src/main/webapp/WEB-INF

11、在WEB-INF 目录下创建web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
  version="4.0">
  <display-name>demo</display-name>
  <servlet>
    <servlet-name>LoginController</servlet-name>
    <servlet-class>com.coding.demo.web.controller.UserLoginController</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LoginController</servlet-name>
    <url-pattern>/login</url-pattern>
  </servlet-mapping>
</web-app>

12、在webapp 目录下创建index.jsp

<%--
  Created by IntelliJ IDEA.
  User: 码出高薪
  Date: 2020/1/8
  Time: 11:36
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录</title>
</head>
<body>
<form action="/login" method="post" >
    用户名:<input name="username" type="text" /> <br>
    密码:<input name="password" type="password" /><br>
    <input type="submit" value="登录"/>
</form>
</body>
</html>

13、在webapp 目录下创建success.jsp

<%--
  Created by IntelliJ IDEA.
  User: 码出高薪
  Date: 2020/1/8
  Time: 12:23
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录成功</title>
</head>
<body>
登录成功
</body>
</html>

14、在webapp 目录下创建fail.jsp

<%--
  Created by IntelliJ IDEA.
  User: 码出高薪
  Date: 2020/1/8
  Time: 12:23
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录失败</title>
</head>
<body>
登录失败
</body>
</html>

15、运行，打开http://localhost:8080