2.servlet 生命周期

1.建Web project“2Servlet_Basic”

2.建包com.amaker.servlet

3.建类“ServletBasic.java”

package com.amaker.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//继承HttpServet,doGet alt+/,sysout alt+/
public class ServletBasic extends HttpServlet {
 /**
  *
  */
 private static final long serialVersionUID = 3616093822222878695L;

 public void init() throws ServletException {
   System.out.println("init");
 }

 protected void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
   System.out.println("doGet");

 }

 protected void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
   System.out.println("doPost");

 }

 protected void service(HttpServletRequest  request, HttpServletResponse response)
   throws ServletException, IOException {
   System.out.println("servlet");


 }
 public void destroy() {
   System.out.println("destroy");
 }
 
 
}

4.web.xml

<?xml version="1.0" encoding="UTF-8"?> 
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> 
<servlet> 
<servlet-name>basicservlet</servlet-name> 
<servlet-class>com.amaker.servlet.ServletBasic</servlet-class> 
</servlet> 
<servlet-mapping> 
<servlet-name>basicservlet</servlet-name> 
<url-pattern>/servlet/basic</url-pattern> 
</servlet-mapping> 
<welcome-file-list> 
<welcome-file>index.jsp</welcome-file> 
</welcome-file-list> 
<login-config> 
<auth-method>BASIC</auth-method> 
</login-config> 
</web-app>

5.MyHtml.html(WebRoot文件夹)

<!DOCTYPE html>
<html>
  <head>
    <title>MyHtml.html</title>
 
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="this is my page">
    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
   
    <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->

  </head>
 
  <body>
<!--先调用service方法，没有service调用post方法，“method”上有注明-->
    <form action="/2Servlet_Basic/servlet/basic" method="post">
     <input type="submit" value ="click">
    </form>
  </body>

</html>

访问：

http://localhost:8080/2Servlet_Basic/MyHtml.html

按钮进入后发现console

　　init

　　servlet

刷新页面 console

　　init

　　servlet

总结：

servlet的生命周期：

（1）加载实例（创建一个servlet实例）

（2）调用init()方法（仅用一次）

（3）调用service方法(每次请求一次，表明多个用户共享一个servlet实例)

（4）调用destory()方法（tomcat销毁时使用）

------------------------------------------------------------------------------------------------------------------------------本娃的学习日记@lily园