?
Solved

Java Socket Program Hangs

Posted on 2009-04-01
5
Medium Priority
?
513 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 400 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 800 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 800 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

Free Tool: Subnet Calculator

The subnet calculator helps you design networks by taking an IP address and network mask and returning information such as network, broadcast address, and host range.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

In this post we will learn how to connect and configure Android Device (Smartphone etc.) with Android Studio. After that we will run a simple Hello World Program.
These days, all we hear about hacktivists took down so and so websites and retrieved thousands of user’s data. One of the techniques to get unauthorized access to database is by performing SQL injection. This article is quite lengthy which gives bas…
This video teaches users how to migrate an existing Wordpress website to a new domain.
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.
Suggested Courses
Course of the Month6 days, 18 hours left to enroll

593 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