mp实现过程

步骤：

　　1，编写配置文件

spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=root

　　2，编写entity类

@Data
public class User {
    @TableId(type = IdType.ID_WORKER)
    private Long id;
    private String name;
    private Integer age;
    private String email;
    private Date createTime;
    private Date updateTime;
}

　　3，编写mapper类

@Repository
public interface UserMapper extends BaseMapper<User> {
　　// 需要继承BaseMapper<T>
}

　　4，再启动类上添加注解：扫描mapper

@SpringBootApplication
@MapperScan("com.nbg.mpdemo1010.mapper")
public class Mpdemo1010Application {

    public static void main(String[] args) {
        SpringApplication.run(Mpdemo1010Application.class, args);
    }

}

　　5，测试

@SpringBootTest
class Mpdemo1010ApplicationTests {
    @Autowired
    private UserMapper userMapper;

    @Test
    void contextLoads() {
        for (User user : userMapper.selectList(null)) {
            System.out.println(user);
        }
    }

    @Test
    void update(){
        com.nbg.mpdemo1010.entity.User user1 = new com.nbg.mpdemo1010.entity.User();
        User user = new User();
        user.setId(2L);
        user.setAge(111);
        int i = userMapper.updateById(user);
        System.out.println(i);
    }
}