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