programming-examples/java/Servlets_Session_Swing_Util/Buffering servlet responses.java

Buffering servlet responses

package com.ack.web.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
  */
public class BufferingServletResponses extends HttpServlet {
  public void doGet( HttpServletRequest req, HttpServletResponse res )
      throws ServletException, IOException {
    res.setContentType( "text/html" );
    PrintWriter pw = res.getWriter();

    // create 32K buffer
    res.setBufferSize( 32 * 1024 );

    pw.println( "everything we send now is buffered " );
    pw.println( "at the server until we reach the " );
    pw.println( "buffer size limit or we do a flush!" );

    // check to see if anything has been sent to the client
    if( res.isCommitted() ) {
      pw.println( "<br>damned, something has been sent" );
    }
    else {
      // clear the buffer, so what has gone before is lost
      res.resetBuffer();

      pw.println( "we are going to clear this as well" );

      // clears buffer, status codes and headers
      res.reset();

      // we've blanked the ContentType header so lets add it back
      res.setContentType( "text/html" );

      pw.println( "<br>but we are going to see this" );
    }

    // send what we have now
    res.flushBuffer();

    pw.println( "<br>and this will get flushed at the end of the method" );
    pw.println( "<br>current response buffer size is: " + res.getBufferSize() );
  }
}