Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

Java Socket Program Hangs

Posted on 2009-04-01
5
503 Views
Last Modified: 2013-11-24
This Java program acquires web content from a website.  I'm having issues with msnbc.com.  After the 24th loop of acquiring content the progam hangs.

So after about the 24th i:, the program stops and then, eventually the socket resets.

Any ideas what could be the problem?  Any suggestions to fix?
OutputStream os = null;
        ByteArrayOutputStream byteContainer = new ByteArrayOutputStream();
        try {
            Socket socket = new Socket("www.msnbc.msn.com", 80);
 
            String r = new String("GET / HTTP/1.1\n" +
                    "Host: www.msnbc.msn.com\n" +
                    "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.12) Gecko/20080201 Firefox/2.0.0.12\n" +
                    "Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5\n" +
                    "Accept-Language: en-us,en;q=0.5\n" +
                    "Accept-Encoding: gzip,deflate\n" +
                    "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\n" +
                    "Keep-Alive: 300\n" +
                    "Connection: keep-alive\n" +
                    "Cookie: MC1=GUID=e72def902864496fa1074688e1697ab7; TZM=-240; __g_c=w%3A0; PageNo=1; s_cc=true; s_sq=%5B%5BB%5D%5D; MUID=F496E73B351C49BF8120BEECED8B6A98\n");
 
            System.out.println("Connecting using the following get request: " + r);
 
            os = socket.getOutputStream();
            boolean autoflush = true;
            PrintWriter out = new PrintWriter(socket.getOutputStream(), autoflush);
            out.println(new String(r));
            out.println('\r');
            out.println('\n');
            out.flush();
            socket.shutdownOutput();
 
            // Read the response
            byte[] b = new byte[1024];
            InputStream in = socket.getInputStream();
            int i = in.read(b);
            while (i != -1) {
                byteContainer.write(b, 0, i);
                i = in.read(b);
                System.out.println("i: " + i);
            }
 
            socket.close();
            in.close();
            out.close();
            os.close();
 
            byte[] content = byteContainer.toByteArray();
            byteContainer.close();
 
        } catch (IOException ex) {
            ex.printStackTrace();
        }

Open in new window

0
Comment
Question by:lcor
5 Comments
 
LVL 17

Assisted Solution

by:Thomas4019
Thomas4019 earned 100 total points
ID: 24044552
Maybe their website is categorizing you calls as excessive. Maybe try waiting for a few hundred milliseconds between each call.
0
 
LVL 92

Accepted Solution

by:
objects earned 200 total points
ID: 24044555
0
 

Author Comment

by:lcor
ID: 24044978
Thomas4019,
I added a Thread.sleep(300) in the while loop.

Each i comes back with a value of 1024 but it eventually ends up hanging.
0
 
LVL 8

Assisted Solution

by:n_sachin1
n_sachin1 earned 200 total points
ID: 24047181
IMHO, the read method of an inputstream is supposed to block till the end of stream is reached or there was an IO error/exception, if there is no more data available to be read. Thats what is happening in your program.

With HTTP1.1 calls, that have persistent connections, the server does not drop the connection after writing the data, but instead, sends information in the packets that the current response is complete(via content-length, etc.). You should look towards using the HTTP classes instead of plain Sockets, as they are higher level abstractions and understand the HTTP packets better.

Use java.net.HttpURLConnection as the entry point, or use the Apache Http Client library which is simpler to use.



0
 

Author Closing Comment

by:lcor
ID: 31565568
n_sachin1 and objects are the solution but Thomas4019 was helpful with debug
0

Featured Post

How Do You Stack Up Against Your Peers?

With today’s modern enterprise so dependent on digital infrastructures, the impact of major incidents has increased dramatically. Grab the report now to gain insight into how your organization ranks against your peers and learn best-in-class strategies to resolve incidents.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

New Relic: Our company recently started researching several products to figure out what were the best ways for us to increase our web page speed and to quickly identify performance problems that we may be having. One of the products we evaluated wa…
Developer tools in browsers have been around for a while, yet they are still heavily underused by developers. Developers still fix html or CSS then refresh page to see effect, or they put alert or debugger in JavaScript and then try again and again …
This tutorial covers a practical example of lazy loading technique and early loading technique in a Singleton Design Pattern.
Learn how to set-up PayPal payment integration in your Wufoo form. Allow your users to remit payment through PayPal upon completion of your online form. This is helpful for collecting membership payments, customer payments, donations, and more.

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question