Web Component to Web Component Communication

 

JSP

            <jsp:include>

                        http://java.sun.com/products/jsp/syntax/1.2/syntaxref1214.html#8828

-include static content, OR content generated from another web component (URL) directly into a .jsp page.  JSP continues to process the page after the content is inserted.

 

<jsp:forward>

http://java.sun.com/products/jsp/syntax/1.2/syntaxref1212.html#15694

-transfer control by forwarding a request to another web component (URL), the clients browser is redirected, but the request object information is forwarded.

 

java.net.*

            url

            httpUrlConnection (subclass of URLConnection)

                        getResponseCode: 200, 401,…

                        getResponseMessage: message associated with code

 

Working with URLs – Java Trail: http://java.sun.com/docs/books/tutorial/networking/urls/index.html

Reading and Writing from an URLConnection: http://java.sun.com/docs/books/tutorial/networking/urls/readingWriting.html

 

      /**

      *     Acts as a web client and fetches the HTML code from the given URL

      *

      *     @Param            URL for HTTP request

      *

      *     @Return           HTML code or the virtual path

      */

 

      private String getThatPage(String p_sUrl) throws Exception

      {

            URL                     url               = null;

            InputStream             isIn              = null;

            DataOutputStream        dosOut;

            String                  sOut              = "";

            StringBuffer            sUrlContent = new StringBuffer();

            BufferedReader          disIn;

 

            try

            {

                  url = new URL (p_sUrl);

                  isIn = url.openStream();

                  disIn = new BufferedReader(new InputStreamReader(isIn));

 

                  while ((sOut = disIn.readLine()) != null)

                  {

                        if (sUrlContent.length() ==0)

                        {     // Url not found

                              if (sOut.indexOf("Error 404")> 0)

                                     throw ( new Exception("Error 404"));

                        }

                        sUrlContent.append("\n" + sOut);

                  }

 

                  disIn.close();

                  isIn.close();

            }

            catch (Exception ex)

            {

                  throw ex;

            }

            finally

            {

                  disIn = null;

                  isIn = null;

                  dosOut = null;

            }

            return sUrlContent.toString();

      }

 

 

 

For posting:

 

HttpURLConnection myHTTPConn = null;

myHttpConn = url.openConnection();

OutputStream os = myHttpConn.getOutputStream();

PrintWriter out = new PrintWriter(os);

while

      out.write

}

out.close();

os.close();

status = myHTTPConn.getResponseCode();

message = myHttpConn.getResponseMessage();

if (status >= HttpURLConnection.HTTP_OK) && (status < HttpUrlConnection.HTTP_MULT_CHOICE)

{

      read response