spring boot整合mybatis

1，导入mybatis的pom依赖

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.4</version>
        </dependency>

2，编写yml配置文件配置数据源和mybatis配置

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/chatroom?serverTimezone=UTC&userUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver
    
mybatis:
  type-aliases-package: com.example.pojo
  mapper-locations: classpath:mybatis/mapper/*.xml

3，编写mapper接口

package com.example.mapper;

import com.example.pojo.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;

//这个注解表示这是一个mybatis的mapper类
@Mapper
@Repository
public interface UserMapper {
    List<User> queryUserList();

    User queryUserById(int id);

    int addUser(User user);

    int updateUser(User user);

    int deleteUser(int id);
}

4，在resources/mybatis/mapper下新建xml配置文件UserMapper.xml配置文件，编写sql语句

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.mapper.UserMapper">

    <select id="queryUserList" resultType="User">
        select * from user
    </select>

    <select id="queryUserById" resultType="User">
        select * from user where id=#{id}
    </select>

    <insert id="addUser" parameterType="User">
        insert into user (id,username, password, type) values (#{id},#{username},#{password},#{type})
    </insert>

    <update id="updataUser" parameterType="User">
        update user set username=#{username},password=#{password}  where id=#{id}
    </update>

    <delete id="deleteUser" parameterType="int">
        delete from user where id=#{id}
    </delete>
</mapper>

5，编写Controller测试

package com.example.controller;

import com.example.mapper.UserMapper;
import com.example.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class UserController {
    @Autowired
    private UserMapper userMapper;

    @GetMapping("/queryUserList")
    public List<User> queryUserList(){
        List<User> list = userMapper.queryUserList();
        for (User user : list) {
            System.out.println(user);
        }
        return list;
    }

    @GetMapping("/delete")
    public String delete(){
        int i = userMapper.deleteUser(101);
        return "ok";
    }
}