Question

For the second time I have this extremely anoying problem with an InputStream.
This InputStream belongs to a Socket that is supposed to receive an image. The code for reading this image is as below:

InputStream input = socket.getInputStream();

InputStreamReader reader = new InputStreamReader(input);
BufferedReader bufferedReader = new BufferedReader(reader);
int total = Integer.parseInt(bufferedReader.readLine());
int bytesRead = 0;
byte[] buffer = new byte[total]; // total is the total size of the image

while (bytesRead < total) {
    int next = input.read(buffer, bytesRead, total-bytesRead);
    if (next > 0) {
        bytesRead += next;
        System.out.println("Read: " + bytesRead);
    }
}

Now the strange thing is that this code skips the first 1182 bytes of the image, and then reads the remaining part. So when the total size is 15000 bytes, it reads byte 1182-15000.

I checked Wireshark and the whole image is transmitted. The code throws no exceptions. input.read() returns -1 as usual.

Pervious data has been readed from the stream using a BufferedReader. This data is only 5 characters long so it can’t contain the missing 1K, but my guess is that the BufferedReader.readLine() method reads (buffers) more bytes from the InputStream than needed. Could this be correct?

I’ve had the same problem a few months ago but I absolutely have no clue on how I solved it.

Hope anyone can help.

Thanks in advance.

EDIT: I can solve the problem by adding a 100 ms sleep between sending the image size and the image data. It solves the problem but I would still realy like to know a more appropriate solution

Answer 1

As the name **Buffererd**Reader indicates it will snarf more bytes than just the first line from the underlying reader and hence also from the stream. Otherwise if would not be called “buffered”.

Unfortunately I’m not aware of any non-deprecated class in Java which allows mixing of binary and textual data in the way you want.

I suggest, that you modify your protocol and transfer the length of the image also in some binary encoding. Then you can stick to InputStream.