使用Java&在MongoDB中存储和检索文件网格文件 [英] Storing and retriving file in MongoDB using Java & GridFs

问题描述

我想将文件存储在mongoDB中，然后从那里检索文件以进行处理. 我已经用GRIDFS来存储它了

I would like to store a file in mongoDB and retrieve it from there to process it. I have used the GRIDFS to store it

 Mongo mongo = new Mongo("localhost", 27017);
    DB db = mongo.getDB("HelloWorldDB");
    DBCollection collection = db.getCollection("Uploaded_Exclusion_files"); 
    GridFS gridfs = new GridFS(db, "downloads");
    GridFSInputFile gfsFile = gridfs.createFile(new File(fileName));
    gfsFile.setFilename("filename");
    gfsFile.save();

    BasicDBObject info = new BasicDBObject();
    info.put("name", "MongoDB");
    info.put("fileName", "filename");
    info.put("rawName", "fromJSON.csv");
    info.put("rawPath", "d:/fromJSON.csv");

    //
    // Let's store our document to MongoDB
    //
    collection.insert(info, WriteConcern.SAFE);


    DBCursor cursor= collection.find(info);
    while(cursor.hasNext()){
        System.out.println("Result "+cursor.next());
    }
        System.out.println("Done");     

但是在检索文件时，我不知道将其作为文件进行处理的方式.

but at the time of retrieving the file I don't l know what to make it as a file and process it.

            GridFSDBFile gfsFileOut = (GridFSDBFile) gridfs.findOne("filename");
            System.out.println(gfsFileOut.getInputStream());
            //##### WHAT TO DO TO GET THE FILE

    BufferedReader br = null;
    try {
        String sCurrentLine;
        br = new BufferedReader(new FileReader(<#####I WANT TO PASS THE FILE TO PROCESS IT######>));

        // ...          
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            if (br != null)
                br.close();
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }

我想删除服务器中的文件创建部分，只想存储在mongodb中并检索它以进行处理.

I want to remove the file creation part in server and only wants to store in mongodb and retrieve it for processing it.

推荐答案

我得到了使用GridFS从MongoDB中获取文件的答案

I got the answer to Get the file from MongoDB using GridFS

GridFSDBFile gfsFileOut = (GridFSDBFile) gridfs.findOne(rawName);
    System.out.println(gfsFileOut.getInputStream());
    InputStream is = gfsFileOut.getInputStream();

    // Reading the excel file
    List<String> list = null;
    BufferedReader br = null;
    try {
        String sCurrentLine;
        br = new BufferedReader(new InputStreamReader(is, "UTF-8"));

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