How JSP returns to the upper page URL

The first:

Enumeration Qnames = Request.getParameterNames ();

String Qstring = "";

While (QNAMES.hasMoreElements ()) {

String Qname = (string) Qnames.nexTelement ();

String [] qValues ​​= request.getParameterValues ​​(QNAME);

For (int J = 0; j

Qstring = qstring java.net.urlencoder.Encode (QNAME) "=" java.net.urlencoder.encode (QVALUES [J]) "&"

}

}

Second:

String REFURL = Request.getHeader ("Referer") "?" Qstring