Multiple POST requests

Question

Greetings everybody,
For this particular question I am not getting any help from the Java forums and Google.
Not very long ago I had to send a stream of bytes from an applet to a servlet (the applet and its helper classes are packed inside a signed jar file), but I used to fail miserably at every step.
I tried every trick in the book (for me the books were Google and Java forums!!). I set the servlet's path in the Windows CLASSPATH, I tried to call the applet from within a servlet- of course after placing the applet file in the servlets folder- (in the hope that since the applet was in the same location as the servlets the URL would get established) e.t.c but still URL url=new URL(<servlet URL>) refused to invoke the servlet.
Finally somehow I managed to get it done using the code below:
public class Xyz extends Applet
//DONT BE SURPRISED RIGHT NOW!!
Class cls=this.getClass();
ClassLoader cldr=cls.getClassLoader();
//THE ACTUAL SERVLET CONNECTING CODE
URL url=cldr.getResource("http://localhost:8000/servlet/<SomeServlet>");
/*This statement does not work........ URL url=new URL("http://localhost:8000/servlet/<SomeServlet>").A NULL URL OBJECT GETS CREATED!! */
HttpURLConnection hurlc=(HttpURLConnection)url.getConnection();
//ALL THE NECESSARY FORMALITIES TO BE PERFORMED TO WRITE THE STREAM TO THE SERVLET
hurlc.setDoInput(false);
hurlc.setDoOutput(true);
hurlc.setUseCaches(false);
hurlc.setRequestMethod("POST");
OutputStream os=hurlc.getOutputStream();
//WRITING THE STREAM
os.write(<some byte buffer>);
//NOW COMES THE TRICKY PART
hurlc.getResponseCode();
I had to do getResponseCode() because once ClassLoader.getResource(<servlet URL>) invoked the servlet using the GET method I COULD NOT INVOKE THE SERVLET AGAIN. I had to force an invokation using getResponseCode().
Well all is well now excepting for a small irritant. Instead of issuing one POST request the URLConnection is issuing multiple POST requests. In the Apache logs I get to see something like:
GET /snodx/callapplet.htm 200 116
GET /snodx/keystore_for_holding_fingerprint_for_trusted_applet 200 234
GET /snodx/applet_and_helpers.jar 200 105
HEAD /servlet/<SomeServlet> 200 187
POST /servlet/<SomeServlet> 200 312
POST /servlet/<SomeServlet> 500 604
POST /servlet/<SomeServlet> 500 604
The last 2 lines indicate that the servlet was invoked but the connection closed somehow. This is confirmed by taking a look at the Apache error logs:
Premature end of script headers.
Premature end of script headers.
In the JServ servlet engine error logs I am getting:
(500)apj12 returned an error handling request
cannot scan servlet headers.
The problem is occurring somewhere in getResponseCode().This statement is invoking the servlet using the request method set (POST) several times (2 or 3 times).
Can someone explain what's going on?
This is briefly the servlet code:
public class SomeServlet extends HttpServlet
//THE SERVICE METHOD IS CALLED BY A HEAD REQUEST TO THIS SERVLET
public void service(ServletRequest reque,ServletResponse respon) throws ServletException,IOException
this.doPost((HttpServletResponse)reque,(HttpServletResponse)respon);
//GO DIRECTLY TO THE POST METHOD
public void doPost(HttpServletRequest req,HttpServletResponse resp) throws ServletException,IOException
ServletInputStream sis=req.getInputStream();
if(sis.available()<2) //CHECK THAT THERE IS STREAM WHICH HAS AT LEAST 2 BYTES OF DATA!!
log("NO STREAM FROM APPLET");
else
//PERFORM ALL ACTIONS TO WRITE TO STREAM OF BYTES TO A LOCAL FILE
I have the servlet engine JServ 1.1.2 configured to run with Apache 1.3.19 on Windows 2000.
I compiled the Applet and the Servlet using JDK1.3 and JSDK2.0. I have JRE 1.3.1_02 installed on my Win2k machine.
Sorry for the long winded story here.
Awaiting a reply.
SNODX
(The search keywords combination getResponseCode multiple POST requests +Applet and many other related keyword combinations did not match any document in the Java forums. The search string "Multiple POST requests" "getResponseCode" and many other related search strings did not match any document in Google.I am continuing the search effort however                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

interresting the classloader solution. Well if that works, i would keep it like that so far.
But maybe this can help:
os.write(<some byte buffer>);
..and then
os.flush()//to make sure the outputstream is sent immediatly.
//i think getResponseCode() is not necsessary in that case
//but not certain, after all ...setUseCaches(false);
One thing you should do is remove the complete
service() {
...this.doPost();
the reason is that when a POST arrives at the servlet, the default service-method of the ancestor class (which is javax.servlet.Servlet) will automaticaly make a call to doPost() of the javax.servlet.http.HttpServlet subclass. You should not overide it I believe.
maybe... -try to establish an OutputStream only once in the Applet.
- receive the other end exactly once (as you did) in the doPost as an InputStream;
- eventually wrap both sides in respective Buffered(In)(Out)putStream(Reader)(Writer)
- start looping and .write() and .read() at both sides on the single and same in-and-outputStream();
(i.e avoid establishing the connection from the applet several times..., get one connection and keep it)
sorry if this story would be irrelevant,
Papyrus