An application talking to a Servlet... problem!

[Vanchi Nathan]

Hello all,

Spec..:
currently i have an Java application trying to send a String data to a Servlet that must receive and save it as a file in the server side. The problem is there occurs an Server 500 error..

D:\codes\classes>java -cp %CLASSPATH% vlv.mjava.Test
java.io.IOException: Server returned HTTP response code: 500 for URL: <a href="http://it-" target="_blank" rel="nofollow">http://it-</a>
pc36924.sf.sp.edu.sg:8000/work/testSt
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown So
urce)
        at vlv.mjava.Test.main(Test.java:30)
 
D:\codes\classes>  

Can anyone figure why this comes... My application code is as follows:

static URL u;
    public static void main(String args[])
    {
String s=URLEncoder.encode("A Test string to send to a servlet");

try
{
   URL u = new URL("http://it-pc36924.sf.sp.edu.sg:8000/work/testSt");
      
    // Open the connection and prepare to POST
    URLConnection uc = u.openConnection();
    uc.setDoOutput(true);
    uc.setDoInput(true);
    uc.setAllowUserInteraction(true);

    DataOutputStream dstream = new DataOutputStream(uc.getOutputStream());
      
    // The POST line
    dstream.writeBytes(s);
    dstream.close();

    // Read Response
    InputStream in = uc.getInputStream();
   /* int x;
    while ( (x = in.read()) != -1)
    {
System.out.write(x);
    }
   */

    BufferedReader r = new BufferedReader(new InputStreamReader(in));
    StringBuffer buf = new StringBuffer();
    String line;
    while ((line = r.readLine())!=null) {
buf.append(line);
    }
 in.close();
} catch (MalformedURLException e2) {
e2.printStackTrace();
}
catch (IOException e)
{ 
    e.printStackTrace();// should do real exception handling
}
    }  

[William Brogden]

It could be this line:

dstream.close();  

When doing a URLConnection you should NEVER close a stream until the response has been read. Use flush() to make sure the request is sent. The reason being that close() causes the socket to be closed.
Bill

[Vanchi Nathan]

Hello William,

Thanks for the response....very

My servlet is a simple one and it works when i invoke by a browser...(codes below):

public void doGet (HttpServletRequest req, HttpServletResponse res) 
throws ServletException, IOException {
res.setContentType("text/plain");
OutputStream out = res.getOutputStream();
 PrintWriter send = new PrintWriter(out);
 send.println("Thanks updated");
 send.flush();
 send.close();
}

...the problem is with the code in the following java application...(codes below):

public static void main(String args[])
    {
BufferedReader r = null;
BufferedWriter bw = null;
try
{
  URL u = new URL("http://164.78.104.122:8080/work/testSt");
     
   // Open the connection and prepare to POST
   URLConnection uc = u.openConnection();
   uc.setDoOutput(true);
   uc.setDoInput(true);
   uc.setAllowUserInteraction(true);

    bw = new BufferedWriter(new OutputStreamWriter(uc.getOutputStream()));
      
    // The POST line
    bw.write("Hello world");
    bw.flush();
    
// to read the response.
    r = new BufferedReader(new InputStreamReader(uc.getInputStream()));
   String line;
    while ((line = r.readLine())!=null) {
System.out.println(line);
    }
 
} catch (MalformedURLException e2) {
e2.printStackTrace();
}
catch (IOException e)
{ 
    e.printStackTrace();// should do real exception handling
} finally {
try {
   bw.close();
   r.close();
} catch (IOException e3) {}
}
    }
 

The error i get is as follows:

 
D:\codes\classes>java -cp %CLASSPATH% vlv.mjava.Test
java.io.IOException: Server returned HTTP response code: 405 for URL: <a href="http://164" target="_blank" rel="nofollow">http://164</a>
.78.104.122:8080/work/testSt
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown So
urce)
        at vlv.mjava.Test.main(Test.java:30)
Exception in thread "main" java.lang.NullPointerException
        at vlv.mjava.Test.main(Test.java:45)
 
D:\codes\classes>

I don't know why the application is not served by the doGet method instead it tell "Unknown Source"...

pl. help...

[Vanchi Nathan]

Correction please..What i stated..

I don't know why the application is not served by the doGet method instead it tell "Unknown Source"...

actually not with doGet method but by doPostmethod..