A brief in JSP client request
When a browser from the client side requests for a web page, it send lots of information to the web server which can not be read directly because
this information travel as a part of header of HTTP request. Now this request are handled by important headers that is sent by our browser while sending the request.
Following are the important header information that comes from browser
part .
Header
|
Description
|
Accept
|
This header says the MIME types that the browser or other clients can
handle. Values of image/png or image/jpeg are the two
most common possibilities.
|
Accept-Charset
|
This header says the character sets the browser can use to display
the information. For example ISO-8859-1.
|
Accept-Encoding
|
This header talk about the types of encodings that the browser knows
how to handle. Values of gzip or compress are the two
most common possibilities.
|
Accept-Language
|
This header says the client's preferred languages in case the servlet
can produce results in more than one language. For example en, en-us, ru,
etc.
|
Authorization
|
This header is used by clients to identify themselves when accessing
password-protected Web pages.
|
Connection
|
This header indicates whether the client can handle persistent HTTP
connections. Persistent connections permit the client or other browser to
retrieve multiple files with a single request. A value
of Keep-Alivemeans that persistent connections should be used
|
Content-Length
|
This header is applicable only to POST requests and gives the size of
the POST data in bytes.
|
Cookie
|
This header returns cookies to servers that previously sent them to
the browser.
|
Host
|
This header specifies the host and port as given in the original URL.
|
If-Modified-Since
|
This header indicates that the client wants the page only if it has
been changed after the specified date. The server sends a code, 304 which means Not
Modified header if no newer result is available.
|
If-Unmodified-Since
|
This header is the reverse of If-Modified-Since; it specifies that
the operation should succeed only if the document is older than the specified
date.
|
Referer
|
This header indicates the URL of the referring Web page. For example,
if you are at Web page 1 and click on a link to Web page 2, the URL of Web
page 1 is included in the Referer header when the browser requests Web page
2.
|
User-Agent
|
This header find out the browser or other client making the request
and can be used to return different content to different types of browsers
|
Example:
JSP File (client-request.jsp)
<%@ page import="java.io.*,java.util.*" %>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
<title>nirajanghimireyworkshop.blogspot.com</title>
</head>
<body>
<center>
<h2>HTTP Header Request Example</h2>
<table width="100%" border="1" align="center">
<trbgcolor="lightsalmon">
<th>Header Name</th><th>Header Value(s)</th>
</tr>
<%
Enumeration headerNames = request.getHeaderNames();
while(headerNames.hasMoreElements()) {
String paramName = (String)headerNames.nextElement();
out.print("<tr><td>" + paramName + "</td>\n");
String paramValue = request.getHeader(paramName);
out.println("<td> " + paramValue + "</td></tr>\n");
}
%>
</table>
</center>
</body>
</html>
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