MyBatisPlius

0、创建表

DROP TABLE IF EXISTS user;

CREATE TABLE user
(
    id BIGINT(20) NOT NULL COMMENT '主键ID',
    name VARCHAR(30) NULL DEFAULT NULL COMMENT '姓名',
    age INT(11) NULL DEFAULT NULL COMMENT '年龄',
    email VARCHAR(50) NULL DEFAULT NULL COMMENT '邮箱',
    PRIMARY KEY (id)
);

DELETE FROM user;

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');

1、导入依赖

    <!--数据库驱动-->
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.23</version> <!-- 使用适当的版本号 -->
</dependency>
<!--lombok-->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
</dependency>
<!--mybatis-plus-->
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.0.5</version>
</dependency>

• 我们使用mybaits-plus可以节省我们大量的代码，尽量不要同时导入mybatis和mybaits-plus

2、连接数据库

spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=PRC&characterEncoding=UTF8
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

3、做一个小测试

• pojo：com.yap.mybatis_plus.mapper

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private Long id;
    private String name;
    private String age;
    private String email;
}

• mapper：com.yap.mybatis_plus.mapper

import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.yap.mybatis_plus.pojo.User;
import org.springframework.stereotype.Repository;

/**
 * @author yap
 * @version 1.0
 */
//在对应的mapper 上面继承基本的类 BaseMapper
@Repository//代表持久层
public interface UserMapper extends BaseMapper<User> {
}

• 启动类：

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
//扫描mapper 文件夹
@MapperScan("com.yap.mybatis_plus.mapper")
@SpringBootApplication
public class MybatisPlusApplication {

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

}

4、测试

• 引入

//继承了BaseMapper,所以的方法都来自父类
//我们也可以编写自己的扩展方法
@Autowired
private UserMapper userMapper;