1.新建项目：

 框架：

                

2.连接数据库 （application.yml）

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    username: root
    password: 115600LX
    driver-class-name: com.mysql.jdbc.Driver
server:
  port: 8080

3.创建实体类User

package com.lixin.sbmybatis.entity;

import javax.persistence.Entity;


public class User {
    private int id;
    private String username;
    private String password;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    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;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

 4.创建User映射的操作UserMapper

package com.lixin.sbmybatis.dao;

import com.lixin.sbmybatis.entity.User;
import org.apache.ibatis.annotations.*;

import java.util.List;

@Mapper
public interface UserMapper {
    @Select("select * from user")
    List<User>findAllUser();

    @Select("select * from user where id= #{id}")
    User findById(@Param("id") int id);

    @Insert("insert into user(username,password) values (#{user.getUsername()},#{user.getPassword()})")
    int addUser(@Param("user") User user);

    @Delete("delete from user where id=#{id}")
    int deleteUser(@Param("id") int id );
}

5.UserService类

（注：需要加上@Transactional注解来开启事务）

package com.lixin.sbmybatis.service;

import com.lixin.sbmybatis.dao.UserMapper;
import com.lixin.sbmybatis.entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;
@Service
@Transactional
public class UserService {
      @Autowired
     private UserMapper userMapper ;


    public List <User>findAllUser(){
        return userMapper .findAllUser() ;
    }
}

 6.UserController

package com.lixin.sbmybatis.controller;

import com.lixin.sbmybatis.entity.User;
import com.lixin.sbmybatis.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class UserController {
    @Autowired
    UserService userService ;

    @RequestMapping("test")
    public List <User >findAllUser(){
       return  userService .findAllUser() ;
    }
}