XML over HTTP between client and server

Question

We are trying to pass XML between a client and servlet over HTTP.
          We used the code from the StockClient/StockServlet examples as a
          starting point but cannot get it to work. Basically we
          have a simple command line java client that is trying to access
          a VERY simple servlet. When the client tries to write data into
          the output stream associated with the connection I get:
          "Connection rejected: 'Login timed out after: '15000' ms....."
          I have read several postings that instruct me to raise the
          timeout limit, but as you can see, I surely don't need 15 seconds
          to write this data out! Is there something special I need to do?
          Does this have anything to do with known issue #10065
          (http://www.weblogic.com/docs51/release_notes/rn_knownprob51.html)
          I have followed all of the instructions in the example code
          (http://www.weblogic.com/docs51/classdocs/xml.html)...
          Any assistance is appreciated...
          here is the client code:
          import java.io.*;
          import java.net.*;
          public class TestClient
          public static void main(String aa[])
          URL url = null;
          HttpURLConnection urlc = null;
          PrintWriter pw = null;
          file://Commented lines indicate other things I have tried
          try
          url = new URL("http://localhost:7001/ParserServlet");
          file://urlc = url.openConnection();
          urlc = (HttpURLConnection)url.openConnection();
          file://urlc.setRequestProperty("Content-Type", "text/xml");
          urlc.setDoOutput(true);
          urlc.setDoInput(true);
          file://urlc.connect();
          pw = new PrintWriter(new OutputStreamWriter
          (urlc.getOutputStream()), true);
          pw.println("<?xml version='1.0'?><test>testing123</test>");
          pw.flush();
          file://urlc.disconnect();
          } catch(IOException ex) {
          System.out.println(ex.getMessage());
          Here is the servlet code:
          import javax.servlet.*;
          import javax.servlet.http.*;
          import java.io.*;
          import java.net.*;
          public class TestServlet extends HttpServlet
          public synchronized void init(ServletConfig config) throws
          ServletException
          super.init(config);
          System.out.println("Inside init()");
          public final void doPost(HttpServletRequest request, HttpServletResponse
          response)
          throws ServletException, IOException
          System.out.println("Inside doPost()");
          protected void doGet(HttpServletRequest req,
          HttpServletResponse resp)
          throws ServletException,
          java.io.IOException
          System.out.println("Inside doGet()");
          

Answer 1

          Jon,
          One thing is missed in your client code. When you use HTTP POST to send request,
          you have two ways to tell the Web server when to stop reading from your input and
          to start process your input: the first one is using "Content-Lenght" header property
          to specify how many bytes you want to send to your servlet, the seocnd is use "Transfer-Code:
          Chunked" and is much more complicated. I didn't see you pass "Content-Length" in
          your client code, in which case, the Web server (Weblogic) cannot know the end of
          your request data and could keep waiting for last byte to come out or waiting for
          the socket time out (that is what you get).
          Since you use servlet, not JSP, I would recommend to code in this way (it works fine
          for me, no guranttee for your situation):
          Client code: Use a big temprary string, or StringBuffer, or StringWriter to store
          all the request data (your xml file content) before you send out the request. After
          you finish to form your XML string, calculate the number of bytes (should equal to
          the length of the string) and add the request header as
          urlc.setRequestProperty("Content-Length", bytes_length);
          I will not suggest you using PrintWriter. Think use BufferedOutputStream constructed
          from URLConnection and write the bytes (use String.getBytes()) to the servlet and
          then flush.
          Servlet code: in the doPost() of your servlet, try to find the request data length
          by calling request.getContentLength(), then open the InputStream (think to use BufferedInputStream
          for performance). Read the contents from the InputStream byte by byte and counter
          the number of bytes. Once you get the number of bytes as specified via request Content-Length,
          break your reading loop and start whatever you want.
          Hope it helps.
          "Jon Clark" <[email protected]> wrote:
          >We are trying to pass XML between a client and servlet over HTTP.
          >We used the code from the StockClient/StockServlet examples as a
          >starting point but cannot get it to work. Basically we
          >have a simple command line java client that is trying to access
          >a VERY simple servlet. When the client tries to write data into
          >the output stream associated with the connection I get:
          >"Connection rejected: 'Login timed out after: '15000' ms....."
          >I have read several postings that instruct me to raise the
          >timeout limit, but as you can see, I surely don't need 15 seconds
          >to write this data out! Is there something special I need to do?
          >Does this have anything to do with known issue #10065
          >(http://www.weblogic.com/docs51/release_notes/rn_knownprob51.html)
          >I have followed all of the instructions in the example code
          >(http://www.weblogic.com/docs51/classdocs/xml.html)...
          >
          >Any assistance is appreciated...
          >
          >here is the client code:
          >import java.io.*;
          >import java.net.*;
          >
          >public class TestClient
          >{
          > public static void main(String aa[])
          > {
          > URL url = null;
          > HttpURLConnection urlc = null;
          > PrintWriter pw = null;
          >
          > file://Commented lines indicate other things I have tried
          > try
          > {
          > url = new URL("http://localhost:7001/ParserServlet");
          > file://urlc = url.openConnection();
          > urlc = (HttpURLConnection)url.openConnection();
          > file://urlc.setRequestProperty("Content-Type", "text/xml");
          > urlc.setDoOutput(true);
          > urlc.setDoInput(true);
          > file://urlc.connect();
          > pw = new PrintWriter(new OutputStreamWriter
          > (urlc.getOutputStream()), true);
          > pw.println("<?xml version='1.0'?><test>testing123</test>");
          > pw.flush();
          > file://urlc.disconnect();
          > } catch(IOException ex) {
          > System.out.println(ex.getMessage());
          > }
          > }
          >}
          >
          >
          >
          >Here is the servlet code:
          >
          >import javax.servlet.*;
          >import javax.servlet.http.*;
          >import java.io.*;
          >import java.net.*;
          >
          >public class TestServlet extends HttpServlet
          >{
          > public synchronized void init(ServletConfig config) throws
          >ServletException
          >
          >
          > super.init(config);
          > System.out.println("Inside init()");
          > }
          >
          > public final void doPost(HttpServletRequest request, HttpServletResponse
          >response)
          > throws ServletException, IOException
          > {
          > System.out.println("Inside doPost()");
          > }
          >
          > protected void doGet(HttpServletRequest req,
          > HttpServletResponse resp)
          > throws ServletException,
          > java.io.IOException
          > {
          > System.out.println("Inside doGet()");
          > }
          >}
          >
          >
          >
          >