Is it possible to check progress of URLconnection.getInputStream()?

Question

I want to check progress of downloading file by URLconnection. Is it possible or should I use another library? This is my urlconnection function:

public static String sendPostRequest(String httpURL, String data) throws UnsupportedEncodingException, MalformedURLException, IOException {
    URL url = new URL(httpURL);

    URLConnection conn = url.openConnection();
    //conn.addRequestProperty("Content-Type", "text/html; charset=iso-8859-2");
    conn.setDoOutput(true);
    OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
    wr.write(data);
    wr.flush();

    BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream(), "ISO-8859-2"));
    String line, all = "";
    while ((line = rd.readLine()) != null) {
        all = all + line;
    }
    wr.close();
    rd.close();
    return all;
}

I understand that whole file is downloaded in this line (or worng)?:

BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream(), "ISO-8859-2"));

So is it possible to do this in this code?

I posted a class that reports read bytes from an `InputStream` using `ChangeListener`. It is transparent and independent of encoding. http://stackoverflow.com/a/10071341/893578 — Sheepy, Apr 16 '15 at 02:35

score 11 · Accepted Answer · edited Jun 20 '20 at 09:12

Just check if the HTTP Content-Length header is present in the response.

int contentLength = connection.getContentLength();

if (contentLength != -1) {
    // Just do (readBytes / contentLength) * 100 to calculate the percentage.
} else {
    // You're lost. Show "Progress: unknown"
}

Update as per your update, you're wrapping the InputStream inside a BufferedReader and reading inside a while loop. You can count the bytes as follows:

int readBytes = 0;

while ((line = rd.readLine()) != null) {
    readBytes += line.getBytes("ISO-8859-2").length + 2; // CRLF bytes!!
    // Do something with line.
}

The + 2 is to cover the CRLF (carriage return and linefeed) bytes which are eaten by BufferedReader#readLine(). More clean approach would be to just read it by InputStream#read(buffer) so that you don't need to massage the bytes forth and back from characters to calculate the read bytes.

Uhm, how are you reading the bytes then? I'd expect that you just read the `connection.getInputStream()` inside a `for` or `while` loop. You just count the read bytes inside this loop. Primary school maths and so on. — BalusC, Mar 01 '11 at 23:19
Do you have any idea how i can make the same but using `HttpURLConnection` when i upload a file to server? Thanks! — Sirop4ik, May 02 '16 at 11:05

score 0 · Answer 2 · answered May 21 '14 at 22:10

    BufferedReader rd = new BufferedReader(new InputStreamReader(new FilterInputStream(conn.getInputStream())
    {
        public int read(byte[] buffer, int byteOffset, int byteCount) throws IOException
        {
            int count = super.read(buffer, byteOffset, byteCount);
            // do whatever with count, i.e. mDownloaded += count;
            return count;
        }
    }, "ISO-8859-2"));

score 0 · Answer 3 · answered Mar 01 '11 at 23:10

0

Wrap it in a javax.swing.ProgressMonitorInputStream. But note that Java may buffer the entire response before it starts delivering it to the stream ...

answered Mar 01 '11 at 23:10

user207421

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Is it possible to check progress of URLconnection.getInputStream()?

3 Answers3

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