春季班未在主要班級自動接線

Question

這是我的SourceRepository類，它不會覆蓋自動返回的Iterable的常規通用findAll（）。

package com.infostream.repositories;

import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.repository.PagingAndSortingRepository;

import com.infostream.models.Source;

public interface SourceRepositoryImpl extends PagingAndSortingRepository<Source, Long>{

    Page<Source> findAll(Pageable pageRequest);

}

這是我的服務班級：

package com.infostream.services;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Component;

import com.infostream.models.Source;
import com.infostream.repositories.SourceRepositoryImpl;

@Component
public class SourcesService {
    @Autowired
    private SourceRepositoryImpl sourceRepository;

    public PageImpl<Source> getPaginatedSources(Pageable pageRequest) {
        Page<Source> searchResultPage = sourceRepository.findAll(pageRequest);
        return new PageImpl<Source>(searchResultPage.getContent(), pageRequest, searchResultPage.getTotalElements()); 
    }

    public Iterable<Source> getAllSources() {
        return sourceRepository.findAll();
    }
}

這是我作為Java應用程序運行的主類。

package com.infostream.services;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.SpringBootApplication;

import com.infostream.consumers.RssArticleConsumer;
import com.infostream.models.Article;
import com.infostream.models.Source;
import com.infostream.producers.RssXmlProducer;

public class HarvestService {

    private static BlockingQueue<Article> article_queue = new ArrayBlockingQueue<Article>(10);

    @Autowired
    private static SourcesService sourcesService;

    public static void main(String[] args) throws InterruptedException {

        Iterable<Source> sources = sourcesService.getAllSources();

        /*
        for(Source s : sources) {
            System.out.println(s.getUrl());
        }

        Thread t1 = new Thread(new RssXmlProducer(sources.iterator().next(), article_queue));
        Thread t2 = new Thread(new RssArticleConsumer(article_queue));

        t1.start();
        t2.start();

        t1.join();
        t2.join();
        */      
    }


}

sourcesService變量為null，我看到自動裝配不起作用，但我不知道為什么。 是因為我通過右鍵單擊包資源管理器中的文件並單擊“以Java應用程序運行”來將HarvestService文件作為Java應用程序運行嗎？

Answer 1

我也遇到了同樣的問題，@ @Autowired在主類中不起作用我所做的是獲取對ApplicationContext的引用，然后使用它來獲取sourcesService作為bean

重寫了您的課程，如下所示

package com.infostream.services;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.SpringBootApplication;
// adedd import file
import org.springframework.context.ApplicationContext;

import com.infostream.consumers.RssArticleConsumer;
import com.infostream.models.Article;
import com.infostream.models.Source;
import com.infostream.producers.RssXmlProducer;

@SpringBootApplication // added this here
public class HarvestService 
{
    private static BlockingQueue<Article> article_queue = new ArrayBlockingQueue<Article>(10);

    @Autowired
    private static SourcesService sourcesService;

    ApplicationContext context; // added this here


    public static void main(String[] args) throws InterruptedException {

        // added this - get reference to application context
        context = SpringApplication.run(HarvestService.class, args);
        // added this - get the object via the context as a bean
        sourcesService = (SourcesService) context.getBean("sourcesService");


        Iterable<Source> sources = sourcesService.getAllSources();

        /*
        for(Source s : sources) {
            System.out.println(s.getUrl());
        }

        Thread t1 = new Thread(new RssXmlProducer(sources.iterator().next(),article_queue));
        Thread t2 = new Thread(new RssArticleConsumer(article_queue));

        t1.start();
        t2.start();

        t1.join();
        t2.join();
        */      
    }
}

Answer 2

您正在使用彈簧靴嗎？ 看起來您的HarvestService類需要@SpringBootApplication並在主函數中添加@SpringBootApplication

SpringApplication.run(HarvestService.class, args);

並確保您在maven / gradle中具有正確的依賴性。 希望能幫助到你

Answer 3

您必須實現CommandLineRunner並將代碼放入方法運行中，因為spring需要加載所有組件，並且使用常規main不能正常工作

@Override
    public void run(String... args) throws Exception {
        main(args);
    }

SpringApplication.run主要方法