POJO
package com.lixiaobin.pojo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
private Integer id;
private String name;
private Integer age;
private String email;
}
mapper
package com.lixiaobin.mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.lixiaobin.pojo.User;
import java.util.List;
public interface UserMapper extends BaseMapper{
}
application.yaml
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.url=jdbc:mysql://localhost:3306/dormitory?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8&rewriteBatchedStatements=true
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
Test
```java
package com.lixiaobin.mapper;
import com.lixiaobin.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
class DemoApplicationTests {
@Autowired
private UserMapper userMapper;
@Test
void contextLoads() {
List<User> list = userMapper.selectList(null);
list.forEach(System.out::println);
}
}
public interface UserMapper extends BaseMapper<User>{}
启动类上面加注解：@MapperScan("com.lixiaobin.mapper")
没看到你写 启动类了， 需要在启动类上加@MapperScan 然后报名等于你mapper类的包，这样才会扫描Mapper
在mapper接口上打上@Mapper注解