servlet面试题（Servlet interview questions）.docVIP

servlet面试题（Servlet interview questions） 1, say the life cycle of Servlet? A: servlet has a good definition of the lifetime, including loading and instantiating, initialization, processing requests, and service completion. This lifetime is made up of the javax.servlet.Servlet interface Init, service, and destroy methods express. After the Servlet is instantiated by the server, the container runs its init method, runs its service method when the request arrives, and the service method automatically sends Run the doXXX method (doGet, doPost) corresponding to the request, and call the destroy method when the server decides to destroy the instance. Unlike CGI, servlet is in the server process; it runs its service method in a multithreaded manner; an instance can serve multiple requests and its instances are generally not destroyed While CGI generates new processes for each request, the service is destroyed after it is completed, so it is less efficient than servlet. The difference between forward () and redirect () in 2, JAVA, SERVLET, API? Answer: the former is only the steering of the control in the container, in the client browser address bar will not show the address after the turn; the latter is a complete jump, the browser will get the address of the jump, and Resend the request link. In this way, you can see the link address after the jump from the browsers address bar. Therefore, the former is more efficient and can be used as much as possible when the former meets the need The forward () method, and this also helps to hide the actual link. In some cases, for example, if you need to jump to resources on a different server, you must use the SendRedirect () method. 3, the basic framework of Servlet Answer: Public, class, ServletName, extends, HttpServlet { Public, void, doPost (HttpServletRequest, request, HttpServletResponse, response) throws ServletException, IOException { } Public, void, doGet (HttpServletRequest, request, HttpServletResponse, response) throws S