GridFS

GridFS介紹

GridFS是MongoDB提供的用於持久化存儲文件的模塊，CMS使用MongoDB存儲數據，使用GridFS可以快速集成開發。

//缺點是效率沒有那麼高效..

 

工作原理的話我在百度找了一張圖,

 

// 詳細的話可以參考 https://docs.mongodb.com/manual/core/gridfs/

 

 

gridfs使用 - . -

存儲文件

 
@Resource
GridFsTemplate gridFsTemplate;

@Test
    public void test2() throws FileNotFoundException {


        File file = new File("D:\\Code\\xuecheng\\XcEduCode\\testfreemark\\src\\main\\resources\\templates\\index_banner.ftl");

        //創建輸入流
        FileInputStream inputStream = new FileInputStream(file);


        //向 gridtemplate 存儲文件

        ObjectId objId = gridFsTemplate.store(inputStream, "輪播圖測試文件", "");

        //id 轉換成字符串格式
        String id = objId.toString();

        System.out.println(id);
//        5bfb661d4402c333342a9c6a
//        gridFsTemplate.store(, );
    }

 

查詢文件

 

1. 需要配置一個bean,這個bean的作用是打開下載流文件

 

import com.mongodb.MongoClient;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.gridfs.GridFSBucket;
import com.mongodb.client.gridfs.GridFSBuckets;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MongoConfig {
    @Value("${spring.data.mongodb.database}")
    String db;
//
    @Bean
    public GridFSBucket getGridFSBucket(MongoClient mongoClient){
        MongoDatabase database = mongoClient.getDatabase(db);
        GridFSBucket bucket = GridFSBuckets.create(database);
        return bucket;
    }
}

  @Resource
    GridFSBucket gridFSBucket;
    //模板查詢
    @Test
    public void fun02() throws IOException {

        String id = "5bfbad494402c33ad0b6dc05";
        GridFSFile fsFile = gridFsTemplate.findOne(Query.query(Criteria.where("_id").is(id)));

        //打開下載流文件
        GridFSDownloadStream gridFSDownloadStream = gridFSBucket.openDownloadStream(fsFile.getObjectId());


        //創建gridFsResource，用於獲取流對象
        GridFsResource gridFsResource = new GridFsResource(fsFile, gridFSDownloadStream);

        //獲取流中的數據
        String s = IOUtils.toString(gridFsResource.getInputStream(), "UTF‐8");

        System.out.println(s);
    }