MyBatisPlus 出现的问题

Question

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);
    }

}

![img](https://img-mid.csdnimg.cn/release/static/image/mid/ask/167051038446159.png "#left")

Answer 1

public interface UserMapper extends BaseMapper<User>{}

启动类上面加注解：@MapperScan("com.lixiaobin.mapper")