导入依赖

普通Maven项目下的依赖

com.baomidou
mybatis-plus
3.4.2

SpringBoot环境下的MP（项目中使用）

com.baomidou
mybatis-plus-boot-starter
3.4.1

MP入门流程分析

1、数据库环境准备
2、创建SpringBoot工程，引入MyBatisPlus的启动器依赖
3、在yml中编写DataSource相关配置
4、编写mapper
5、测试

入门案例

SpringBoot 整合 MyBatis-Plus，并==实现根据Id查询功能==。

1.数据库环境准备

CREATE DATABASE /!32312 IF NOT EXISTS/mp_db /!40100 DEFAULT CHARACTER SET utf8 /;

USE mp;

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

— ——————————————
— Table structure for tb_user 没有给自增
— ——————————————
DROP TABLE IF EXISTS tb_user;
CREATE TABLE tb_user (
id bigint(20) NOT NULL AUTO_INCREMENT,
user_name varchar(255) DEFAULT NULL,
password varchar(255) DEFAULT NULL,
name varchar(255) DEFAULT NULL,
age int(11) DEFAULT NULL,
email varchar(255) DEFAULT NULL,
PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

— ——————————————
— Records of tb_user
— ——————————————
BEGIN;
INSERT INTO tb_user VALUES (1, ‘赵一伤’, ‘123456’, ‘zys’, 19, ‘zys@itcast.cn’);
INSERT INTO tb_user VALUES (2, ‘钱二败’, ‘123456’, ‘qes’, 18, ‘qes@itcast.cn’);
INSERT INTO tb_user VALUES (3, ‘孙三毁’, ‘123456’, ‘ssh’, 20, ‘ssh@itcast.cn’);
INSERT INTO tb_user VALUES (4, ‘李四摧’, ‘123456’, ‘lsc’, 20, ‘lsc@itcast.cn’);
INSERT INTO tb_user VALUES (5, ‘周五输’, ‘123456’, ‘zws’, 20, ‘zws@itcast.cn’);
INSERT INTO tb_user VALUES (6, ‘吴六破’, ‘123456’, ‘wlp’, 21, ‘wlp@itcast.cn’);
INSERT INTO tb_user VALUES (7, ‘郑七灭’, ‘123456’, ‘zqm’, 22, ‘zqm@itcast.cn’);
INSERT INTO tb_user VALUES (8, ‘王八衰’, ‘123456’, ‘wbs’, 22, ‘wbs@itcast.cn’);
INSERT INTO tb_user VALUES (9, ‘张无忌’, ‘123456’, ‘zwj’, 25, ‘zwj@itcast.cn’);
INSERT INTO tb_user VALUES (10, ‘赵敏’, ‘123456’, ‘zm’, 26, ‘zm@itcast.cn’);
INSERT INTO tb_user VALUES (11, ‘赵二伤’, ‘123456’, ‘zes’, 25, ‘zes@itcast.cn’);
INSERT INTO tb_user VALUES (12, ‘赵三伤’, ‘123456’, ‘zss1’, 28, ‘zss1@itcast.cn’);
INSERT INTO tb_user VALUES (13, ‘赵四伤’, ‘123456’, ‘zss2’, 29, ‘zss2@itcast.cn’);
INSERT INTO tb_user VALUES (14, ‘赵五伤’, ‘123456’, ‘zws’, 39, ‘zws@itcast.cn’);
INSERT INTO tb_user VALUES (15, ‘赵六伤’, ‘123456’, ‘zls’, 29, ‘zls@itcast.cn’);
INSERT INTO tb_user VALUES (16, ‘赵七伤’, ‘123456’, ‘zqs’, 39, ‘zqs@itcast.cn’);
COMMIT;

SET FOREIGN_KEY_CHECKS = 1;

2.

创建工程，引入场景依赖

3.编写DataSource相关配置

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

如果想在mybatis-plus自行是看打印的sql，可配置
#mybatis-plus配置控制台打印完整带参数SQL语句
mybatis-plus:
configuration:
log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

4.编码

实体类：
package com.itheima.pojo;

import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
@TableName(“tb_user”) // 指定表名
@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
public class User {
private Long id;
private String userName;
private String password;
private String name;
private Integer age;
private String email;
}
编写mapper：
package com.itheima.mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.itheima.pojo.User;

/*
使用mp定义Mapper，需要让Mapper接口继承 BaseMapper接口。
*/
public interface UserMapper extends BaseMapper {

}

启动类增加 @MapperScan 注解
package com.itheima;

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

@SpringBootApplication
@MapperScan(“com.itheima.mapper”)
public class MpApplication {
public static void main(String[] args) {
SpringApplication.run(MpApplication.class, args);
}
}

测试

package com.itheima;

import com.itheima.mapper.UserMapper;
import com.itheima.pojo.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class UserMapperTest {

@Autowired<br />    private UserMapper userMapper;
@Test<br />    public void testFindById(){<br />        User user = userMapper.selectById(1);<br />        System.out.println(user);<br />    }<br />}