SpringBoot整合Mybatis 引入maven依赖

（IDEA建项目的时候直接选就可以了）

	org.mybatis.spring.boot
	mybatis-spring-boot-starter
	2.1.4

配置application.yml文件

server:
 port: 8144
spring:
 #redis
 redis:
  host: 127.0.0.1
  port: 6379
  password: 123456
  timeout: 3000
 datasource:
  username: root
  password: root
  driver-class-name: com.mysql.cj.jdbc.Driver
  url: jdbc:mysql://localhost:3306/hellomybatis?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8

建实体类、Controller类、Service类 实体类

package com.example.mybatisDemo.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class User {
  private long id;
  private String name;
  private String pwd;
}

Controller类

package com.example.mybatisDemo.controller;

import com.example.mybatisDemo.entity.User;
import com.example.mybatisDemo.service.UserService;
import org.springframework.web.bind.annotation.*;

import java.util.*;


@RestController
@RequestMapping("api/user")
public class UserController {
  private final UserService userService;

  public UserController(UserService userService) {
    this.userService = userService;
  }

  @GetMapping()
  public List getAllUsers(){
    return userService.getUsers();
  }

  @DeleteMapping("{id}")
  public int deleteUser(@PathVariable long id){
    return userService.deleteUser(id);
  }

  @PostMapping
  public int saveUser(@RequestBody User user){
    return userService.insertUser(user);
  }

  @PutMapping
  public int updateUser(@RequestBody User user){
    return userService.updateUser(user);
  }

  @GetMapping("{id}")
  public User getUser(@PathVariable long id){
    return userService.getUser(id);
  }
}

Service类

package com.example.mybatisDemo.service;

import com.example.mybatisDemo.entity.User;
import com.example.mybatisDemo.repository.UserRepository;
import org.springframework.stereotype.Service;
import java.util.*;


@Service
public class UserService {
  private final UserRepository userRepository;

  public UserService(UserRepository userRepository) {
    this.userRepository = userRepository;
  }

  public List getUsers(){
    return userRepository.getUsers();
  }

  public int deleteUser(long id){
    return userRepository.deleteUser(id);
  }

  public User getUser(long id){
    return userRepository.getUser(id);
  }

  public int updateUser(User user){
    return userRepository.updateUser(user);
  }

  public int insertUser(User user){
    return userRepository.addUser(user);
  }
}

建Repository类

package com.example.mybatisDemo.repository;

import com.example.mybatisDemo.entity.User;
import org.apache.ibatis.annotations.*;
import org.springframework.stereotype.Repository;

import java.util.*;

/**
 * Mapper注解能省去以前复杂的xml配置，直接用注解写sql语句
 * 不添加Repository注解依赖注入会报错（不影响运行），强迫症还是加上吧
 */
@Mapper
@Repository
public interface UserRepository {
  @Select("select * from user")
  List getUsers();

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

  @Insert("insert into user(id,name,pwd) values (#{id},#{name},#{pwd})")
  int addUser(User user);

  @Update("update user set name=#{name},pwd=#{pwd} where id = #{id}")
  int updateUser(User user);

  @Select("select * from user where id = #{id}")
  User getUser(long id);
}