SpringBoot整合Mybatis

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.6.4
         
    
    com.example
    demo
    0.0.1-SNAPSHOT
    demo
    Demo project for Spring Boot
    
        1.8
    


    
        
            org.springframework.boot
            spring-boot-starter-data-jdbc
        

        
            org.springframework.boot
            spring-boot-starter-web
        


        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            2.2.2
        


        
            mysql
            mysql-connector-java
            runtime
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        

    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

在resource文件夹下创建application.yml配置文件（备注：其实SpringBoot底层会把application.yml文件解析为application.properties），本文创建了两个yml文件（application.yml和application-dev.yml），分别来看一下内容

spring:
  profiles:
    active: dev

server:
  port: 8080

spring:
  datasource:
    username: root
    password: 1234
    url: jdbc:mysql://localhost:3306/mybatis?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC
    driver-class-name: com.mysql.jdbc.Driver

mybatis:
#  配置MyBatis的Mapper.xml文件所在位置:
  mapper-locations: classpath:mapper
@Repository
public interface UserMapper {

    User Sel(int id);
}

    
        
        
        
        
    
    
        select * from user where id = #{id}
    
    

package com.example.demo.service;

import com.example.demo.entity.User;
import com.example.demo.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;


@Service
public class UserService {

    
    @Autowired
    UserMapper userMapper;

    public User Sel(int id){
        return userMapper.Sel(id);
    }
}

package com.example.demo.controller;

import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;



@RestController
@RequestMapping("/testBoot")
public class UserController {

    
    @Autowired
    private UserService userService;

    @RequestMapping("getUser/{id}")
    public String GetUser(@PathVariable int id){
        return userService.Sel(id).toString();
    }
}

 完成以上，下面在启动类里加上注解用于给出需要扫描的mapper文件路径

 @MapperScan("com.example.demo.mapper")

package com.example.demo;

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



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

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

}

最后启动，浏览器输入地址看看吧：http://localhost:8080/testBoot/getUser/1