Chapter 18. Working With the Client Request
number of web applications must examine
the client request before sending a
response. An example is a servlet that
has to read (or sniff) the browser type
(often through the
header). Servlets or other web
components read information about the
request by examining HTTP request
are composed of header names followed by
colon characters and their values, such
en. The headers precede any
message body that the client is sending
to the server, such as text that has
been posted from an HTML form.
Here is an example of a group of request headers sent with a request for a JSP named contextBind.jsp:
GET /home/contextBind.jsp HTTP/1.1 User-Agent: Opera/5.02 (Windows NT 4.0; U) [en] Host: localhost:9000 Accept: text/html, image/png, image/jpeg, image/gif, image/x-xbitmap, */* Accept-Language: en Accept-Encoding: deflate, gzip, x-gzip, identity, *;q=0 Cookie: mycookie=1051567248639; JSESSIONID=1D51575F3F0B17D26537338B5A29DB1D Connection: Keep-Alive
The recipes in this chapter show how to examine request headers with servlet and JSPs, use filters to alter requests, automatically refresh servlets and JSPs, and count the number of application requests.
18.1. Examining HTTP Request Headers in a Servlet
You want to examine the HTTP request headers in a servlet.
) methods to access the names and ...