Re: Servlet making HTTP requests

Question

Hi,
          We are using an application that uses a servlet to perform some JDBC calls
          (which take about 30 minutes) and then make some HTTP requests (which takes
          about 5 to 10 minutes) to another application.
          Once the client has made the request to initiate this process it waits for
          the complete process (40 minutes) to complete. I know this is not ideal but
          its what we've got to live with.
          After a minute or so after the servlet has started making the HTTP requests
          the browser stops responding and has a blank frame displayed instead of the
          response data. We have assumed that after the servlet makes the HTTP
          requests the other application it is not interacting with the HTTP session
          on the server the client is connected to and a timeout occurrs. This
          termintes the request and is why we see a blank frame. Is this correct ? The
          HTTP requests complete successfully in the background.
          Any advice would be greatly appreciated.
          Kev
          

Answer 1

          Your application is really tough and interesting. Web browser usually has timeout
          limit. Proxy server also has timeout limit (usually 30 seconds). If no communication
          after such kind of timeout limit, your browser will stop.
          When your code calls getWriter() or getOutputStream(), your servlet will flush
          all HTTP response header data to your browser and your browser then will get the
          response from your servlet. Beyond that, if you don't send any data from your
          servlet to your browser before proxy or browser timeout, you can only get a blank
          screen.
          If you want to monitor how your servlet works, try to BUILD INTERCATION. At least,
          send data from your servlet to your browser for each time interval which will
          not be longer than browser/proxy timeout. You can send out any information you
          like, if your browser understand it. NOTE YOU SHOULD EXPLICITLY CALL FLUSH() of
          your OutputStream() or Writer() to flush() your data following each write(). This
          way, you can keep the connection alive.
          On the other hand, you can also try set content-length field of response to some
          predefined number, and set Connection field as Keep-Alive, before you call getWriter()
          or getOutputStream(). Then send some data to your browser, for example, one byte
          at a time, until you have sent the number of bytes as specified.
          "Kev" <[email protected]> wrote:
          >Hi,
          >
          >We are using an application that uses a servlet to perform some JDBC
          >calls
          >(which take about 30 minutes) and then make some HTTP requests (which
          >takes
          >about 5 to 10 minutes) to another application.
          >
          >Once the client has made the request to initiate this process it waits
          >for
          >the complete process (40 minutes) to complete. I know this is not ideal
          >but
          >its what we've got to live with.
          >
          >After a minute or so after the servlet has started making the HTTP requests
          >the browser stops responding and has a blank frame displayed instead
          >of the
          >response data. We have assumed that after the servlet makes the HTTP
          >requests the other application it is not interacting with the HTTP session
          >on the server the client is connected to and a timeout occurrs. This
          >termintes the request and is why we see a blank frame. Is this correct
          >? The
          >HTTP requests complete successfully in the background.
          >
          >Any advice would be greatly appreciated.
          >
          >Kev
          >
          >