Http Request Headers Display in a JSP page
A JSP page can access the information in the
request header by using the implicit object request. An Http client sends a
request, it sends the request in the form of get or post method or any other
Http Request methods. It can also sends the headers with it.
Here is the list of most commonly used headers are
Accept |
The MIME types the browser prefers. |
Accept-
Encoding |
The types of data
encodings the browser knows how to decode. |
Accept- Charset |
The character set the
browser expects. |
Content-Length |
It is mostly used for POST messages,
it tells how much data is attached. |
Cookie |
It is one of the most frequently used
headers, it returns the cookies. |
Accept- Language |
The language the browser is expecting. |
There are many another headers , here we are
going to develop an application in JSP to show the request headers.
For developing the application we follow the following steps
Steps 1: Create a new web application
First we use an web application in java web and click on the next button
Steps 2: Name and Location
In this step we use a specific name and location to the project
Step 3: Select server and setting
In this step we select a specific server GlassFish 3.1 and java EE 6 version
Step 4: Select Framework
There is no need to select any framework for this application
Step 5: Create a new jsp file
In this step we create a new jsp file index.jsp.
Index.jsp
<%@ page import="java.util.*"
%>
<html>
<body bgcolor="cyan">
<h1>HTTP Request
Headers Received</h1>
<table border="1"
cellpadding="4" cellspacing="0">
<%
Enumeration eNames = request.getHeaderNames();
while (eNames.hasMoreElements())
{
String name = (String) eNames.nextElement();
String value = normalize(request.getHeader(name));
%>
<tr><td><%= name %></td><td><%=
value %></td></tr>
<%
}
%>
</table>
</body>
</html>
<%!
private String normalize(String value)
{
StringBuffer sb = new StringBuffer();
for (int i = 0; i < value.length(); i++) {
char c = value.charAt(i);
sb.append(c);
if (c == ';')
sb.append("<br>");
}
return sb.toString();
}
%>
Compiling and Running the application
Now we first compile it and run it on server and then we will see the output as:
Output
index.jsp
In this application we will get the information about all the headers, and
the information which we will get from this example. Through 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.