入门案例

创建测试数据库和表

CREATE DATABASE `mybatis_plus` /*!40100 DEFAULT CHARACTER SET utf8mb4 */; use `mybatis_plus`;CREATE TABLE `user` ( `id` bigint(20) NOT NULL COMMENT '主键ID',`name` varchar(30) DEFAULT NULL COMMENT '姓名', `age` int(11) DEFAULT NULL COMMENT '年龄', `email` varchar(50) DEFAULT NULL COMMENT '邮箱', PRIMARY KEY (`id`) )ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO user (id, name, age, email) VALUES 
(1, 'Jone', 18, 'test1@baomidou.com'), 
(2, 'Jack', 20, 'test2@baomidou.com'), 
(3, 'Tom', 28, 'test3@baomidou.com'),(4, 'Sandy', 21, 'test4@baomidou.com'), (5, 'Billie', 24, 'test5@baomidou.com');

创建SpringBoot工程

引入依赖

<!--        mybatis plus 启动器--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.1</version></dependency><!--        lombok用于简化实体类开发--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency><!--        mysql驱动--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope></dependency>

idea中安装lombok插件

配置application.yml

spring:# 配置数据源信息datasource:# 配置数据源类型type: com.zaxxer.hikari.HikariDataSource# 配置连接数据库的各个信息driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=UTC&&characterEncoding=utf- 8&useSSL=falseusername: rootpassword: password

创建实体类

package com.xxxx.mybatisplus.pojo;import lombok.*;//@NoArgsConstructor
//@AllArgsConstructor
//@Getter
//@Setter
//@EqualsAndHashCode
@Data
public class User {// mybatis plus默认用雪花算法, id 会比较长private Long id;private String name;private Integer age;private String email;}

添加mapper

package com.xxxx.mybatisplus.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.xxxx.mybatisplus.pojo.User;// 将类或者接口标记为持久层组件 这样就不会看见test类中的红线警告了 
@Repository
public interface UserMapper extends BaseMapper<User> {}

在启动类上添加注解扫描mapper

package com.xxxx.mybatisplus;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication// 扫描mapper接口所在的包
@MapperScan("com.xxxx.mybatisplus.mapper")
public class MybatisplusApplication {public static void main(String[] args) {SpringApplication.run(MybatisplusApplication.class, args);}}

测试

package com.xxxx.mybatisplus;import com.xxxx.mybatisplus.mapper.UserMapper;
import com.xxxx.mybatisplus.pojo.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;import java.util.List;@SpringBootTest
public class MyBatisPlusTest {@Autowiredprivate UserMapper userMapper;@Testpublic void testSelectList(){// 通过条件构造器查询一个list集合,若没有条件,则可以设置null为参数List<User> list = userMapper.selectList(null);list.forEach(System.out::println);}}

加入日志功能

加入配置

mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl