CODEWITHSUNDEEP
javagoogle-app-enginegoogle-cloud-storage
Mohamed Kawia
Mohamed Kawia

Reputation: 21

App Engine / Google Cloud storage Input stream error

I am having a problem with writing bytes of a retrieved ObjectInputStream object. I need this to be able to access the file in the format.

This is the code I am currently using:

public ObjectInputStream serve(String fileName) throws IOException,
        ClassNotFoundException {

    GcsFilename gcsFileName = getFileName(fileName, defaultbucketName);

    int fileSize = (int) gcsService.getMetadata(gcsFileName).getLength();
    GcsInputChannel readChannel = null;

    readChannel = gcsService.openPrefetchingReadChannel(gcsFileName, 0,
            fileSize);

    try (ObjectInputStream oin = new ObjectInputStream(
            Channels.newInputStream(readChannel))) {
        return oin;
    }


}

When I run the code it fails at the line ObjectInputStream oin = new ObjectInputStream(Channels.newInputStream(readChannel)) with an error, e.g.:

java.io.StreamCorruptedException: invalid stream header: FFD8FFE0

However there are no problems when I emmit the stream to a HTTPRESPONSE object.

Upvotes: 2

Views: 585

Answers (1)

Matoe
Matoe

Reputation: 2758

You are likely attempting to access a file which hasn't been written by a ObjectOutputStream, which contains a special header.

Therefore, to access the file you should either rewrite its contents with the Google Cloud Storage writing APIs or with a dummy Java program like this one:

FileOutputStream fos = new FileOutputStream("test.txt");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject("your content");
oos.close();

Later, upload test.txt to your GCS bucket.

Upvotes: 2

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