Servlet生命周期

    开讲了.

    Servlet部署再容器里面. 它的生命周期由容器管理.

   1.装载Servlet 这项操作一般是动态执行的.

   2.创建一个Servlet实例.

  3. 调用Servlet的init()方法;

  4.接收请求.调用Servlet的service()方法.

  5.销毁. 实例被销毁.调用Servlet的distory()方法进行销毁

  下面来开发一个简单的Servlet

 

//每一个JSP页面进行编译的时候.都会装换成Servlet源文件

package com.Servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class Demo extends HttpServlet {

 public void destroy() {
  super.destroy(); // Just puts "destroy" string in log
     //这个是销毁的方法
 }

 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

    //当用户是用doGet方法提交请求是. 我们调用该方法处理请求

    this.doPost(request,reponse);
 }

 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  response.setContentType("text/html");
  PrintWriter out = response.getWriter();
 //业务逻辑处理
  out.flush();
  out.close();
 }

 public void init() throws ServletException {
  //init方法调用

 }

}