Springboot集成Mybatis

1 添加依赖(这里引用的是5.7驱动包)

     <dependency>
           <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

2 配置数据库连接
设置application.properties文件，添加如下配置

#Mybatis配置
spring.datasource.url=jdbc:mysql://localhost:3306/demo?characterEncoding=utf8&characterSetResults=utf8&autoReconnect=true&failOverReadOnly=false
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
mybatis.type-aliases-package=com.example.demo.xk.mapper

spring.datasource.url 数据库连接字符串
spring.datasource.username 数据库用户名
spring.datasource.password 数据库密码
spring.datasource.driver-class-name 驱动类型（注意MySQL 8.0的值是com.mysql.cj.jdbc.Driver和之前不同）
mybatis.type-aliases-package 配置mapper包名
Mapper文件说明

Mapper是MyBatis的核心，是SQL存储的地方，也是配置数据库映射的地方。
3 设置 MapperScan 包路径
直接在启动文件SpringbootApplication.java的类上配置@MapperScan，这样就可以省去，单独给每个Mapper上标识@Mapper的麻烦。

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan(value = "com.example.demo.xk.mapper")
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

4 添加测试代码
User 类：

package com.example.demo.xk.entity;

public class User {
    private Long id;
    private String name;
    private Integer age;
    
    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

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

UserMapper 接口：

package com.example.demo.xk.mapper;

import com.example.demo.xk.entity.User;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

public interface UserMapper {
    @Select("select * from user where id = #{id}")
    User queryUserById(@Param(value = "id") int id);
}

Controller 控制器：

package com.example.demo.xk.controller;

import com.example.demo.xk.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {
    @Autowired
    private UserMapper userMapper;
    
    @RequestMapping("/query")
    public Object queryById(int id){
        return userMapper.queryUserById(id);
    }
    
}

OK