我尝试使用Sping Boot 创建REST服务，但在服务和存储库之间使用@Autowired时遇到问题。
回答后编辑：
这是我的代码：
实体名称

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;
    }

}

资料档案库

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
}

服务

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;
    }
}

这是回溯

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:

至少应有1个符合自动连接候选条件的Bean。依赖关系注解：{}