I'm trying to create a REST Service using Spring Boot and I'm having problems using @Autowired between Service and Repositories.

EDIT AFTER ANSWERS:

This is my code:

Entity

import javax.persistence.*;

@Entity
@Table(name= Constants.USERS, schema = Constants.SCHEMA)
public class Users {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;   //<----like this
    @Column(name = "username", nullable = false)
    private String username;

    @Column(name = "lastname", nullable = false)
    private String lastname;

    public Users() {
    }

    public Users(String username, String lastname) {
        this.username = username;
        this.lastname = lastname;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getLastname() {
        return lastname;
    }

    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

}

Repository

   import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public interface UsersRepository extends JpaRepository<Users,Integer> {

    public List<Users> findAll();
    public long count(); // and no need to define function here
}

Service

    import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UsersService{

    private UsersRepository usersRepository;

    @Autowired
    public UsersService(UsersRepository usersRepository) {
        this.usersRepository = usersRepository;
    }


    public long count() {
        long conteggio = usersRepository.count();
        return conteggio;
    }
}
    

This is the traceback

Error creating bean with name 'usersService' .Unsatisfied dependency expressed through 
constructor paramet
er 0; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.repository.UsersRepository' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}.
No qualifying bean of type 'com.intesasanpaolo.dsi.core.bear.ptrm0.connector.jpa.UsersRepository' available:

expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}

CodePudding user response：

It seems you do not have any primary key in your User table.

JPA requires that every entity has an ID. So no, entity w/o an ID is not allowed. Try adding a primary key of type Integer as it is required when extending to the JPa repository as the second argument passed is the type of primary key. You can define a field as primary key by using @Id annotation. You can do something like below:

package com.model;
import javax.persistence.*;

@Entity
@Table(name=Constants.USERS, schema = Constants.SCHEMA)
public class Users {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY) 
    private int id;   //<----like this
@Column(name= "username", nullable=false)
private String username;

@Column(name="lastname", nullable = false)
private String lastname;

public Users() {
}

public Users(String username, String lastname) {
    this.username = username;
    this.lastname = lastname;
}

public Long getId() {
    return id;
}

public void setId(Long id) {
    this.id = id;
}

public String getUsername() {
    return username;
}

public void setUsername(String username) {
    this.username = username;
}

public String getLastname() {
    return lastname;
}

public void setLastname(String lastname) {
    this.lastname = lastname;
}

}

Keep your repository same

Also , you do not have to write @Autowire on the field as the constructor will automatically inject the bean to the field

@Autowired   // this is not necessary you can remove this too
    private final UsersRepository usersRepository;

    public UsersService(UsersRepository usersRepository) {
        this.usersRepository = usersRepository;
    }

Also, I think you should be extending to JpaRepository like below instead of JpaConnector

@Repository
public interface UsersRepository extends JpaRepository<Users,Integer> {

    public List<Users> findAll();
    public long count(); // and no need to define function here
}

CodePudding user response：

    public UsersService(UsersRepository usersRepository) {
        this.usersRepository = usersRepository;
    }

try removing this contructor