SSM 示例

User 实体类

package com.itheima.domain;

import java.io.Serializable;

public class User implements Serializable {

    private Integer id;       //用户id
    private String name;      //用户名称
    private String password;  //用户密码
    private String email;     //用户邮箱（用户账号）
    private String role;      //用户角色
    private String status;    //用户状态

    // get, set ......
}

UserMapper

package com.itheima.mapper;
import com.itheima.domain.User;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;

public interface UserMapper{
    @Select("select * from user where user_email=#{email} AND user_password=#{password} AND user_status!='1'")
    @Results(id = "userMap",value = {
            //id字段默认为false，表示不是主键
            //column表示数据库表字段，property表示实体类属性名。
            @Result(id = true,column = "user_id",property = "id"),
            @Result(column = "user_name",property = "name"),
            @Result(column = "user_password",property = "password"),
            @Result(column = "user_email",property = "email"),
            @Result(column = "user_role",property = "role"),
            @Result(column = "user_status",property = "status")
    })
    User login(User user);
}

UserService 接口

package com.itheima.service;
import com.itheima.domain.User;
/**
 *用户接口
 */
public interface UserService{
    //通过User的用户账号和用户密码查询用户信息
    User login(User user);
}

UserService 接口实现

package com.itheima.service.impl;
import com.itheima.domain.User;
import com.itheima.mapper.UserMapper;
import com.itheima.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
/**
 *用户接口实现类
 */
@Service
public class UserServiceImpl  implements UserService {
    //注入userMapper
    @Autowired
    private UserMapper userMapper;

    //通过User的用户账号和用户密码查询用户信息
    @Override
    public User login(User user) {

        return userMapper.login(user);
    }
}

 MyBatis-Spring 提供了一个动态代理的实现——MapperFactoryBean。这个类可以让你直接注入数据映射器接口到你的 service 层 bean 中。当使用映射器时,你仅仅如调用你的 DAO 一样调用它们就可以了,但是你不需要编写任何 DAO 实现的代码,因为 MyBatis-Spring将会为你创建代理。同样，MapperFactoryBean创建的代理控制开放和关闭 session。

    @Bean
    public MapperScannerConfigurer getMapperScannerConfigurer(){
        MapperScannerConfigurer msc = new MapperScannerConfigurer();
        //等同于<property name="basePackage" value="com.itheima.dao"/>
        msc.setBasePackage("com.itheima.mapper");
        return msc;
    }

UserController

package com.itheima.controller;
import com.itheima.domain.User;
import com.itheima.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
/**
 * 用户登录和注销Controller
 */
@Controller
public class UserController {
    @RequestMapping("/toMainPage")
    public String  toMainPage(){
        return "main";
    }

    //注入userService
    @Autowired
    private UserService userService;

    /*    用户登录    */
    @RequestMapping("/login")
    public String login(User user, HttpServletRequest request){
        try {
            User u=userService.login(user);
            /*
            用户账号和密码是否查询出用户信息
                是：将用户信息存入Session，并跳转到后台首页
                否：Request域中添加提示信息，并转发到登录页面
             */
            if(u!=null){
                request.getSession().setAttribute("USER_SESSION",u);
                 return "redirect:/admin/main.jsp";
            }
            request.setAttribute("msg","用户名或密码错误");
            return  "forward:/admin/login.jsp";
        }catch(Exception e){
            e.printStackTrace();
            request.setAttribute("msg","系统错误");
            return  "forward:/admin/login.jsp";
        }
    }
    
}