Java — How to read an unknown number of bytes from an inputStream (socket/socketServer)?

Question

Looking to read in some bytes over a socket using an inputStream. The bytes sent by the server may be of variable quantity, and the client doesn\'t know in advance the lengt

Answer 1

Without re-inventing the wheel, using Apache Commons:

IOUtils.toByteArray(inputStream);

For example, complete code with error handling:

    public static byte[] readInputStreamToByteArray(InputStream inputStream) {
    if (inputStream == null) {
        // normally, the caller should check for null after getting the InputStream object from a resource
        throw new FileProcessingException("Cannot read from InputStream that is NULL. The resource requested by the caller may not exist or was not looked up correctly.");
    }
    try {
        return IOUtils.toByteArray(inputStream);
    } catch (IOException e) {
        throw new FileProcessingException("Error reading input stream.", e);
    } finally {
        closeStream(inputStream);
    }
}

private static void closeStream(Closeable closeable) {
    try {
        if (closeable != null) {
            closeable.close();
        }
    } catch (Exception e) {
        throw new FileProcessingException("IO Error closing a stream.", e);
    }
}

Where FileProcessingException is your app-specific meaningful RT exception that will travel uninterrupted to your proper handler w/o polluting the code in between.