Controller.Controller 中的错误字段存储库需要找不到类型为“Controller.Repository”的 bean

Question

I'm trying to connect my Controller to Repository in one of the spring application but I'm getting an error saying "Field tweetRepository in TweetsController.TweetsController required a bean of type 'TweetsController.TweetRepository' that could not be found."

Can someone help me with this? Thanks in advance. I've attached code samples as well.

TwitterApplication.java

package SpringMVC.Twitter;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;

@SpringBootApplication
@ComponentScan("AuthController")
@ComponentScan("TweetsController")
public class TwitterApplication {

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

TwitterController.java

package TweetsController;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.Optional;

@RestController
public class TweetsController {

    @Autowired
    private TweetRepository tweetRepository;

    @RequestMapping("/tweets")
    public Iterable<TweetsContent> getAllTweets() {
        return tweetRepository.findAll();
    }

    @RequestMapping("tweet/{id}")
    public Optional<TweetsContent> getTweet(@PathVariable int id) {
        return tweetRepository.findById(id);
    }

    @RequestMapping(method = RequestMethod.POST, value = "/tweets")
    public boolean addTweet(@RequestBody TweetsContent tweet) {
        TweetsContent t = tweetRepository.save(new TweetsContent(tweet.getTitle(), tweet.getContent()));
        if (t != null)
            return true;
        else
            return false;
    }
}

TwitterRepository.java

package TweetsController;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface TweetRepository extends CrudRepository<TweetsContent, Integer> { }

Answer 1

Add the spring data dependency on your pom:

<dependency>
       <groupId>org.springframework.boot</groupId>
       <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

Answer 2

Add this too. @ComponentScan("TweetRepository")

Answer 3

You don't need to use @ComponentScan("AuthController") and @ComponentScan("TweetsController") because if you use @SpringBootApplication, scanning will occur from the package of the class that declares this annotation. But you need to put TwitterApplication like this:

Answer 4

You don't have to specify @ComponentScan in your TwitterApplication , because spring boot application is scanning its own directory at the startup. and remove the @Repository annotation from your repository class, it is also not needed.