AB Infinity feb 2014 | Página 5

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Chapter 5

Accessing the Standard CGI Variables

REMOTE_HOST
REMOTE_HOST indicates the fully qualified domain name (e.g., whitehouse.gov) of the client that made the request. The IP address is

returned if the domain name cannot be determined. You can access this
variable with request.getRemoteHost().
REMOTE_USER
If an Authorization header was supplied and decoded by the server
itself, the REMOTE_USER variable gives the user part, which is useful
for session tracking in protected sites. Access it with request.getRemoteUser(). For decoding Authorization information directly in
servlets, see Section 4.5 (Restricting Access to Web Pages).
REQUEST_METHOD
This variable stipulates the HTTP request type, which is usually GET or
POST but is occasionally HEAD, PUT, DELETE, OPTIONS, or TRACE. Servlets
rarely need to look up REQUEST_METHOD explicitly, since each of the
request types is typically handled by a different servlet method (doGet,
doPost, etc.). An exception is HEAD, which is handled automatically by
the service method returning whatever headers and status codes the
doGet method would use. Access this variable by means of
request.getMethod().
SCRIPT_NAME
This variable specifies the path to the servlet, relative to the server’s root
directory. It can be accessed through request.getServletPath().
SERVER_NAME
SERVER_NAME gives the host name of the server machine. It can be
accessed by means of request.getServerName().

SERVER_PORT
This variable stores the port the server is listening on. Technically, the
servlet equivalent is String.valueOf(request.getServerPort()),
which returns a String. You’ll usually just want request.getServerPort(), which returns an int.
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Servlet and JSP training courses by book’s author: courses.coreservlets.com.