Request Headers in JSP
Whenever an http client sends a request, it sends the request in the form of get or post method or any other HttpRequest methhods. It can also sends the headers with it. All the headers are optional except Content-length, which is required only for POST requests. Here is the list of most commonly used headers are:
1) Accept : The MIME types the browser prefers.
2) Accept- Encoding: The types of data encodings the browser knows how to decode.
3) Accept- Charset: The character set the browser expects.
4) Content-Length: It is mostly used for POST messages, it tells how much data is attached.
5) Cookie: It is one of the most frequently used headers, it returns the cookies.
6) Accept- Language: The language the browser is expecting.
There are many more request headers availables. These headers you can see in the output of the program.
In this example we are going to retrieve all the headers available in the request object. We can retrieve these by using the Enumeration interface of the java.util package. Use while condition to check whether there are more headers or not. And at last print the headers on the browsers by using the out implicit object.
The code of the program is given below:
<%@ page import = " java.util.* " %>
<html>
<head>
<title>Getting a header in Jsp</title>
</head>
<body>
<%
Enumeration enumeration = request.getHeaderNames();
while (enumeration.hasMoreElements()) {
String string = (String)enumeration.nextElement();
out.println("<font size = 6
>" +string +": " + request.getHeader(string)+ "</font><br>");
}
%>
</body>
</html>
|
Output of the program is given below:
