MATLAB: Mongo and GridFS Java Driver with MATLAB

Question

I am trying to upload and download pictures from MATLAB to MongoDB using the Mongo Java Driver.

I am following below tutorial on GridFS java:

http://mongodb.github.io/mongo-java-driver/3.10/driver/tutorials/gridfs/#prerequisites

In MATLAB I did :

javaaddpath("C:\Users\****\Documents\jar_files\mongo-java-driver-3.11.0-beta3.jar")
import com.mongodb.Block;
import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.gridfs.*;
import com.mongodb.client.gridfs.model.*;
import org.bson.Document;
import org.bson.types.ObjectId;
import java.io.*;
import java.nio.file.Files;
import java.nio.charset.StandardCharsets;
import com.mongodb.client.model.Filters.eq;
mongoClient = MongoClients.create();
myDatabase = mongoClient.getDatabase("TestData");
gridFSFilesBucket = GridFSBuckets.create(myDatabase, "PicturesTest");
streamToUploadFrom = FileInputStream(File("C:\Users\****\Pictures\MyPicture.png"));

Until that point it works but then I can't do the following line:

fileId = gridFSBucket.uploadFromStream("mongodb-tutorial", streamToUploadFrom)

I get follwing error message ;

Undefined variable "gridFSBucket" or class "gridFSBucket.uploadFromStream".

I do not get why it is not able to find gridFSBucket function in the java driver.

I tried to play with the jar files it worked once but is not working anymore (do not know what I did exactly)…

Any help is much appreciated.

Thanks.

Answer 1

The error occurs because there is no such object "gridFSBucket".

You need to create an object "gridFSBucket" of type GridFSBucket. Just add this line to your code:

 gridFSBucket = GridFSBuckets.create(myDatabase);

Then add this:

fileId = gridFSBucket.uploadFromStream("mongodb-tutorial", streamToUploadFrom);