org.springframework.boot
spring-boot-starter-parent
2.7.5
com.brevity
mp
0.0.1-SNAPSHOT
mp
Mybatis-Plus Demo
1.8
org.springframework.boot
spring-boot-starter
org.springframework.boot
spring-boot-starter-test
test
com.baomidou
mybatis-plus-boot-starter
3.5.2
org.projectlombok
lombok
true
mysql
mysql-connector-java
runtime
junit
junit
新建数据库mp,创建user表,插入了10条数据,SQL如下:
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 `mp`.`user` (`id`, `name`, `age`, `email`) VALUES
(1, 'Tom', 18, '[email protected]'),
(2, 'Jack', 20, '[email protected]'),
(3, 'Brevity', 28, '[email protected]'),
(4, 'Brevity_520', 22, '[email protected]'),
(5, 'Billie', 24, '[email protected]'),
(6, 'Jone', 18, '[email protected]'),
(7, 'Jack', 20, '[email protected]'),
(8, 'John', 28, '[email protected]'),
(9, 'Sandys', 21, '[email protected]'),
(10, 'Bill', 24, '[email protected]');
在application.properties配置文件中添加数据库配置,具体内容如下所示:
spring.datasource.url=jdbc:mysql://localhost:3306/mp?serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=root
在SpringBoot启动类中添加@MapperScan注解,用来扫描Mapper文件夹,如下所示:
@SpringBootApplication
@MapperScan("com.brevity.mp.mapper")
public class MpApplication {
public static void main(String[] args) {
SpringApplication.run(MpApplication.class, args);
}
}
编写User实体类以及UserMapper接口:
@Data // Lombok注解
public class User implements Serializable {
private static final long SerialVersionUID = 1L;
private Long id;
private String name;
private Integer age;
private String email;
}
public interface UserMapper extends BaseMapper {
}
编写测试类开始测试代码:
@SpringBootTest
class MpApplicationTests {
@Autowired
private UserMapper userMapper;
@Test
void testMp() {
System.err.println("-------select method--------");
List userList = userMapper.selectList(null);
Assert.assertEquals(10, userList.size());
userList.forEach(System.out::println);
}
}
至此,入门代码已经编写完毕,且测试成功,可以看到,没有编写任何xml文件就实现了查询,仅需要添加maven依赖,配置扫描注解即可,这就是它的强大之处之一。