This chapter presents focused discussions of topics related to creating responses from a servlet. The organization of this chapter loosely follows the typical order in which a servlet creates a response. The chapter describes each topic in isolation. See Chapter 9, “Creating Servlets,” for an example of a complete servlet.

Servlets that rely on maintaining state between requests most often let the servlet container manage state using sessions (“Saving Session State” ). A servlet creates HTTP headers for the response (“Creating HTTP Headers” ). The servlet may create the content of the response directly (“Creating an HTTP Response” ). If the servlet generates HTML, the response may contain a URL back to the servlet (“Creating an HTTP Response” ). If the servlet cannot fulfill the request, the servlet returns an HTTP error (“Returning an Error” ), redirects the client (“Redirecting the Client” ), or obtains the response from another servlet in the servlet container or another location on the Web (“Forwarding a Request” ).

This section follows the conventions that request is a rwsf::HttpServletRequest object, that response is a rwsf::HttpServletResponse object and that any standalone lines of code occur within a servlet function such as doPost().