Talk about the servlet (i)

Servlet 1. To use the servlet first to introduce the Servlet.jar in the application

2. Then, in the. java file

Import Javax.servlet.http.HttpServletRequest;
Import Javax.servlet.http.HttpServletResponse;
Import Javax.servlet.http.HttpServlet;
Import javax.servlet.ServletException;
Import java.io.IOException;
Import Java.io.PrintWriter; This import is visible in the specific case

3. Introduce several common methods in the servlet

A) protected void service (Httpserlvetrequest req,httpservletresponse res) throws servletexception,ioexception{}

If it is overwrite, doxxx method may not be invoked.

b) protected void doget (Httpserlvetrequest req,httpservletresponse res) throws servletexception,ioexception{}

Features 1:safe and idempotent. 2:only ASCII (text) data can is sent to server and get method. 3:easy to bookmarks.

Main function: Get the data, do not change the data

c) protected void DoPost (Httpserlvetrequest req,httpservletresponse res) throws servletexception,ioexception{}

Features 1:not safe and idempotent. 2disallow bookmarks.

Main role: Transmission form data, large quantities of data, commonly used in BBS and other data storage can change the place

There's something else to talk about next time.