JavaEE----------Servlet

来源：互联网发布：hl线切割编程系统编辑：程序博客网时间：2024/06/10 00:18

import java.io.IOException;import javax.servlet.Servlet;import javax.servlet.ServletConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;public class FirstServlet implements Servlet{//第一次访问该servlet时会执行1次构造和init方法，而且只执行。后面再有请求时，这两个方法不会再执行了public FirstServlet() {System.out.println("构造方法.....");}@Overridepublic void init(ServletConfig config) throws ServletException {//初始化System.out.println("init.....");String chars = config.getInitParameter("char");System.out.println(chars);}@Overridepublic ServletConfig getServletConfig() {return null;}//每一次请求都会执行一次@Overridepublic void service(ServletRequest req, ServletResponse res)throws ServletException, IOException {System.out.println("提供服务service......");}@Overridepublic String getServletInfo() {return null;}<pre name="code" class="java"><span style="white-space:pre"></span>//servlet消亡时会执行一次@Overridepublic void destroy() {System.out.println("destroy.......");}}

//在web.xml中设置初始化参数

<pre name="code" class="html"><servlet>  <servlet-name>one</servlet-name>  <servlet-class>cn.hncu.servlet.FirstServlet</servlet-class>  <init-param>  <param-name>char</param-name>  <param-value>utf-8</param-value>  </init-param>  </servlet>

//在web.xml中设置<span style="font-family: Arial, Helvetica, sans-serif;"><load-on-startup></span><span style="font-family: Arial, Helvetica, sans-serif;">服务器启动时就new并初始化，数值代表顺序 </span>

<servlet>  <servlet-name>two</servlet-name>  <servlet-class>cn.hncu.servlet.FirstServlet</servlet-class>  <!-- 配置该load-on-startup选项的servlet会在服务器启动时就new并初始化，数值代表顺序 -->  <load-on-startup>5</load-on-startup>  </servlet>

注意：上面两个servlet会生成两个servlet，它们分别是单例。

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