TCP connection is not reused for HTTP requests with HttpURLConnection

java connection httpurlconnection persistent
plithner picture plithner · Mar 28, 2011 · Viewed 9.3k times · Source

I'm have created an application which sends GET requests to a URL, and then downloads the full content of that page.

The client sends a GET to e.g. stackoverflow.com, and forwards the response to a parser, which has the resposibility to find all the sources from the page that needs to be downloaded with subsequent GET requests.

The method below is used to send those GET requests. It is called many times consecutively, with the URLs returned by the parser. Most of those URLs are located on the same host, and should be able to share the TCP connection.

public static void sendGetRequestToSubObject(String RecUrl)
    {
        URL url = new URL(recUrl.toString());
        URLConnection connection = url.openConnection ();
        InputStreamReader isr = new InputStreamReader(connection.getInputStream());
    }

Each time this method is called, a new TCP connection is created (with a TCP 3-way handshake) and the GET is then sent on that connection. But I want to reuse the TCP connections, to improve performance.

I guess that since I create a new URL object each time the method is called, this is the way it going to work...

Maybe someone can help me do this in a better way?

Thanks!

Answer

Joachim Sauer picture Joachim Sauer · Mar 28, 2011

HttpURLConnection will reuse connections if it can!

For this to work, several preconditions need to be fulfilled, mostly on the server side. Those preconditions are described in the article linked to above.

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