java - 考虑在您的配置中定义类型为 'com.gisapp.gisapp.dao.IUserDAO' 的 bean

Question

当我启动我的 spring-boot 应用程序时，我收到以下消息:

APPLICATION FAILED TO START

---

Description:

Field userDAO in com.gisapp.services.impl.UserService required a bean of type 'com.gisapp.gisapp.dao.IUserDAO' that could not be found.

The injection point has the following annotations: - @org.springframework.beans.factory.annotation.Autowired(required=true)

Action:

Consider defining a bean of type 'com.gisapp.gisapp.dao.IUserDAO' in your configuration.

我在与此问题相关的其他帖子中读到的是我必须配置注释@ComponentScan，但它不起作用

主要类(class):

package com.gisapp.gisapp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@ComponentScan("com.gisapp")
public class GisappApplication {

    public static void main(String[] args) {
        SpringApplication.run(GisappApplication.class, args);
    }

}

服务等级

@Service
public class UserService implements IUserService {

    @Autowired
    IUserDAO userDAO;

    @Override
    @Transactional(readOnly=true)
    public  Object login() {


        return userDAO.login();
    }

}

-UserDAO

package com.gisapp.gisapp.dao.impl;

import java.util.List;

import javax.persistence.EntityManager;
import javax.persistence.Query;

import com.gisapp.gisapp.dao.IUserDAO;
import com.gisapp.models.entity.User;

public class UserDAO implements IUserDAO{

    @Override
    public Object login() {

        StringBuilder query = new StringBuilder();

        query.append("SELECT * FROM User");

        EntityManager em = null;
        Query q = em.createNativeQuery(query.toString());

        List<User> result=q.getResultList();

        return result;

    }

}

IUserDAO 应该被识别为一个 bean 并且应用程序应该运行

Answer 1

1) 添加 @Repository 注解，以便将 DAO 作为 bean 加载到 spring 上下文中:

@Repository
public class UserDAO implements IUserDAO{

2) 就在旁边..您很可能还应该在其中注入(inject) EntityManager :

@PersistenceContext
private EntityManager em;