iTP Secure WebServer System Administrator's Guide (iTPWebSvr 6.0+)

Using NonStop Servlets for JavaServer Pages
(NSJSP)
iTP Secure WebServer System Administrator’s Guide—523346-002
9-32
Classes that Facilitate Servlet Usage in an iTP
Secure WebServer Environment
Classes that Facilitate Servlet Usage in an iTP Secure
WebServer Environment
HttpServlet
This class extends the class GenericServlet by overriding the
service(ServletRequest,ServletResponse) method, which receives,
processes, and responds to a request from a web client. The HttpServlet class
inherits the init(ServletConfig) and destroy() methods from the
GenericServlet class.
A servlet that you write for the iTPWebServer environment must extend either the
GenericServlet class or the HttpServlet class; the HttpServlet class is
preferable for the web environment because it includes many features supporting
HTTP protocol. Your servlet should override the init(ServletConfig) method to
perform any necessary initialization, the
service(ServletRequest,ServletResponse) or
service(HttpServletRequest,HttpServletResponse) method to process
requests as the application requires, and the destroy() method to deallocate
resources gracefully.
Your servlet should also use the doGet() and doPost() methods where applicable.
HttpServletRequest
This class extends the ServletRequest class, which provides methods for retrieving
information from a standard input stream and obtaining the values of various headers
and environment variables. The HttpServletRequest class defines methods for
obtaining http-protocol header information and CGI environment variables such as
QUERY_STRING, PATH_INFO, and PATH_TRANSLATED.
To obtain an enumeration of all CGI environment variables in effect for a servlet, use
the getAttribute() method with the string parameter value
"com.tandem.servlet.attribute_names"
HttpServletResponse
This class extends the ServletResponse class, which provides methods for writing
to the standard output stream and error file. The HttpServletResponse class
defines methods for sending http response headers and error information to the web
client.
To generate its own response headers, a servlet must generate all such headers
before writing any data to the output stream; otherwise, the ServletOutputStream
class sends only the following header:
CONTENT_TYPE=text/html