Head First Servlets and JSP, 2nd Edition

Chapter 4. Request and Response: Being a Servlet

Servlets live to service clients. A servlet’s job is to take a client’s request and send back a response. The request might be simple: “get me the Welcome page.” Or it might be complex: “Complete my shopping cart check-out.” The request carries crucial data, and your servlet code has to know how to find it and how to use it. The response carries the info the browser needs to render a page (or download bytes), and your servlet code has to know how to send it. Or not... your servlet can decide to pass the request to something else (another page, servlet, or JSP) instead.

OBJECTIVES

The Servlet Technology Model

1.1	For each of the HTTP Methods (such as GET, POST, HEAD, and so on), describe the purpose of the method and the technical characteristics of the HTTP Method protocol, list triggers that might cause a client (usually a Web browser) to use the Method, and identify the HttpServlet method that corresponds to the HTTP Method.
1.2	Using the HttpServletRequest interface, write code to retrieve HTML form parameters from the request, retrieve HTTP request header information, or retrieve cookies from the request.
1.3	Using the HttpServletResponse interface, write code to set an HTTP response header, set the content type of the response, acquire a text stream for the response, acquire a binary stream for the response, redirect an HTTP request to ...