APPLICATION FAILED TO START error encountered on SpringBoot - spring

Question

I'm self-studying in Spring boot application and encountered this problem. Weird thing is that I only followed the tutorial but still encountered this
Parameter 0 of constructor in com.example.Project1.service.PersonService required a bean of type 'com.example.Project1.dao.PersonDao' that could not be found.
I have one controller, 2 DAO files, 1 Person for model and 1 for service class.
These are my codes:
PersonController:
package com.example.Project1.api;
import com.example.Project1.model.Person;
import com.example.Project1.service.PersonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#RequestMapping("api/v1/person")
#RestController
public class PersonController {
private final PersonService personService;
#Autowired
public PersonController(PersonService personService){
this.personService = personService;
}
#PostMapping
public void addPerson(#RequestBody Person person){
personService.addPerson(person);
}
}
FakePersonDataAccessService
package com.example.Project1.dao;
import com.example.Project1.model.Person;
import org.springframework.stereotype.Repository;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
#Repository("fakeDao")
public class FakePersonDataAccessService implements PersonDao {
private static List<Person> DB = new ArrayList<>();
#Override
public int insertPerson(UUID id, Person person){
DB.add(new Person(id, person.getName()));
return 1;
}
}
PersonDao
package com.example.Project1.dao;
import com.example.Project1.model.Person;
import java.util.UUID;
public interface PersonDao {
int insertPerson(UUID id, Person person);
default int insertPerson(Person person){
UUID id = UUID.randomUUID();
return insertPerson(id, person);
}
}
Person
package com.example.Project1.model;
import com.fasterxml.jackson.annotation.JsonProperty;
import java.util.UUID;
public class Person {
private final UUID id;
private final String name;
public Person(#JsonProperty("id") UUID id, #JsonProperty("name") String name){
this.id = id;
this.name = name;
}
public UUID getId(){
return id;
}
public String getName(){
return name;
}
}
PersonService
package com.example.Project1.service;
import com.example.Project1.dao.PersonDao;
import com.example.Project1.model.Person;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.stereotype.Service;
#Service
public class PersonService {
private final PersonDao personDao;
#Autowired
public PersonService(#Qualifier("mongo") PersonDao personDao){
this.personDao = personDao;
}
public int addPerson(Person person){
return personDao.insertPerson(person);
}
}
I've tried googling the error but found no answer. Hope someone can enlighten me about the error encountered. Thank you~!

Answer 1

You only have "fakeDao" qualifier class that implements PersonDao but your injecting "mongo" qualifier. As another option, you can just removed the #Qualifier annotation in PersonService constructor since you only have one class that implements PersonDao