Mybatis-Plus 官网：https://mp.baomidou.com/
注解使用：https://mp.baomidou.com/guide/annotation.htm
Github：https://github.com/baomidou/mybatis-plus

1、什么是MyBatis-Plus

MyBatis-Plus（简称 MP）是一个 MyBatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。
mybatis plus 官网
建议安装 MybatisX 插件

只需要我们的Mapper继承 BaseMapper 就可以拥有crud能力

2、Quick start

mybatis-plus quick start：https://baomidou.com/guide/quick-start.html

文件目录结构

2.1、引入 MyBatis-Plus

<dependency>
  <groupId>com.baomidou</groupId>
  <artifactId>mybatis-plus-boot-starter</artifactId>
  <version>3.4.2</version>
</dependency>

2.2、配置 @MapperScan 注解

如果是放在主程序所在的包，@MapperScan 注解可以不写参数。

package com.example.boot;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@MapperScan("com.example.boot")
@SpringBootApplication
public class SpringBootApiTest01Application {
    public static void main(String[] args) {
        SpringApplication.run(SpringBootApiTest01Application.class, args);
    }
}

2.3、编写 Bean

Role

package com.example.boot.bean;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.Data;
@Data
@TableName("t_s_role")
public class Role {
    private String id;
    private String rolecode;
    private String rolename;
    private String role_type;
}

2.4、编写 Mapper 接口

继承 BaseMapper
RoleMapper

package com.example.boot.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.example.boot.bean.Role;
public interface RoleMapper extends BaseMapper<Role> {
}

2.5、编写 controller

/role 接口，当不传递 id 时

package com.example.boot.controller;
import com.example.boot.mapper.RoleMapper;
import com.example.boot.response.Response;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
@RestController
@Slf4j
public class RoleController extends BaseRestController {
    public RoleController() {
        log.info("RoleController 构造函数被调用了");
    }
    @Autowired
    private RoleMapper roleMapper;
    @GetMapping(path = {
            "/role",
    })
    public Response role(@RequestParam(name = "id", defaultValue = "") String id) {
        if (id == null || id.length() <= 0) {
            // 查全部 role
            return success("ok", roleMapper.selectList(null));
        } else {
            // 查单个 role
            return success("ok", roleMapper.selectById(id));
        }
    }
}

2.7、测试

单个
http://127.0.0.1/role?id=8a8ab0b246dc81120146dc8181870050

多个
http://127.0.0.1/role