10.6
Servlet的层次结构
Servlet---》GenericServlet---》HttpServlet
HTTP请求有很多类型,常用的有四种:
GET 读取
POST 保存
PUT 修改
DELETE 删除
CRUD(增删改查):C-Create R-Read U-Update D-Date
GenericServlet实现Servlet接口,同时为它的子类屏蔽了不常用的方法,子类只需要重写service方法即可。
HttpServlet继承GenericServlet,根据请求类型进行分发处理,GET进入doGet方法,POST进入doPost方法。
开发者自定义的Servlet类只需要继承HttpServlet即可,重新doGet和doPost。
package com.wdy.servlet; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet("/test") public class TestServlet extends HttpServlet{ @Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub resp.getWriter().write("GET"); } @Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // TODO Auto-generated method stub resp.getWriter().write("POST"); } }