'com.example.mybatisplus.mapper.PersonMapper' that could not be found.

There are usually two reasons, configuration reason, or mapper relevant documents, mapper.java internal error or mapper.xml

If the configuration is the reason

1 solution

Unified configuration mapper

// Import org.mybatis.spring.annotation.MapperScan; 
Import org.springframework.boot.SpringApplication;
 Import org.springframework.boot.autoconfigure.SpringBootApplication;

 @SpringBootApplication
 @MapperScan ( "com.example.mybatisplus.mapper")   // put this together, do not write on the right path, if it is modular general path @MapperScan ( "com.kfit. *. mapper   ")

public class Application {

    public static void main(String[] args){
        System.out.println("hahahaha");
         SpringApplication.run(Application.class, args);
    }

    
}

Solution 2

Each mapper file configuration @Mapper

package com.example.mybatisplus.mapper;

//import org.apache.ibatis.annotations.Mapper;

import com.baomidou.mybatisplus.mapper.BaseMapper;
import com.example.mybatisplus.entity.Person;
@Mapper     //每个文件配置这个
public interface PersonMapper extends BaseMapper<Person> { 
  Integer listCount(); 
  Person findPersonById(Integer id); 
}

Both can be used in combination