网站维护会导致打不开网页吗?,提高网站排名怎么做,win2008 wordpress,123手机浏览器文章目录 一、目的二、原理三、过程1. TestServlet02文件演示效果2. TestServlet03文件演示效果3. TestServlet04与TestServlet05文件演示效果4. 控制台展示生命周期过程 四、代码web.xml文件TestServlet02.java文件TestServlet03.java文件TestServlet04.java文件TestServlet05… 文章目录 一、目的二、原理三、过程1. TestServlet02文件演示效果2. TestServlet03文件演示效果3. TestServlet04与TestServlet05文件演示效果4. 控制台展示生命周期过程 四、代码web.xml文件TestServlet02.java文件TestServlet03.java文件TestServlet04.java文件TestServlet05.java文件SomeServlet.java文件 一、目的 Servlet接口及其实现类的使用 Servlet虚拟路径映射的配置 使用Eclipse工具开发Servlet Servlet的生命周期
二、原理
Servlet由Servlet容器提供所谓的Servlet容器是指提供了Servlet 功能的服务器本书中指TomcatServlet容器将Servlet动态的加载到服务器上。
Servlet的生命周期
Servlet的生命周期是指Servlet从被Servlet容器加载、初始化到处理客户端请求直至销毁的整个过程。以下是Servlet生命周期的详细介绍
三、过程
1. TestServlet02文件演示效果
(1) 通过getServletConfig()函数获取初始化参数里面内容。
(2) 通过get()展示获取到的参数内容 2. TestServlet03文件演示效果
(1) 通过getServletContext()函数获取参数内容 (3) 通过get()展示获取到的参数内容 3. TestServlet04与TestServlet05文件演示效果
(1) 文件4设置参数文件5获取参数 (2) 通过get()展示获取到的参数内容 4. 控制台展示生命周期过程 代码段 四、代码
web.xml文件
?xml version1.0 encodingUTF-8?
web-app xmlns:xsihttp://www.w3.org/2001/XMLSchema-instance xmlnshttps://jakarta.ee/xml/ns/jakartaee xsi:schemaLocationhttps://jakarta.ee/xml/ns/jakartaee https://jakarta.ee/xml/ns/jakartaee/web-app_5_0.xsd idWebApp_ID version5.0!-- display-namechapter03/display-name --!-- 3.4.1 小结配置信息 --servletservlet-nameTestServlet02/servlet-nameservlet-classcn.itcast.servlet.TestServlet02/servlet-classinit-paramparam-nameencoding/param-nameparam-valueUTF-8/param-value/init-param/servletservlet-mappingservlet-nameTestServlet02/servlet-nameurl-pattern/TestServlet02/url-pattern/servlet-mapping!-- 3.4.2 配置信息 --context-paramparam-namecompanyName/param-nameparam-valueitcast/param-value/context-paramcontext-paramparam-nameaddress/param-nameparam-valuebeijing/param-value/context-paramservletservlet-nameTestServlet03/servlet-nameservlet-classcn.itcast.servlet.TestServlet03/servlet-class/servletservlet-mappingservlet-nameTestServlet03/servlet-nameurl-pattern/TestServlet03/url-pattern/servlet-mappingservletdescription/descriptiondisplay-nameTestServlet04/display-nameservlet-nameTestServlet04/servlet-nameservlet-classcn.itcast.servlet.TestServlet04/servlet-class/servletservlet-mappingservlet-nameTestServlet04/servlet-nameurl-pattern/TestServlet04/url-pattern/servlet-mappingservletdescription/descriptiondisplay-nameTestServlet05/display-nameservlet-nameTestServlet05/servlet-nameservlet-classcn.itcast.servlet.TestServlet05/servlet-class/servletservlet-mappingservlet-nameTestServlet05/servlet-nameurl-pattern/TestServlet05/url-pattern/servlet-mappingwelcome-file-listwelcome-fileindex.html/welcome-file!-- welcome-fileindex.jsp/welcome-filewelcome-fileindex.htm/welcome-filewelcome-filedefault.html/welcome-filewelcome-filedefault.jsp/welcome-filewelcome-filedefault.htm/welcome-file --/welcome-file-list
/web-app TestServlet02.java文件
package cn.itcast.servlet;
import java.io.*;import jakarta.servlet.ServletConfig;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;public class TestServlet02 extends HttpServlet {/*** */private static final long serialVersionUID 1L;Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stub
// super.doGet(req, resp);PrintWriter out resp.getWriter();// 获得ServletConfig对象ServletConfig config this.getServletConfig();// 获得参数名为encoding对应的参数值String param config.getInitParameter(encoding);out.println(encoding param);}Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stubsuper.doPost(req, resp);}
}
TestServlet03.java文件
package cn.itcast.servlet;
import java.io.*;
import java.util.*;import jakarta.servlet.ServletContext;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;public class TestServlet03 extends HttpServlet {/*** */private static final long serialVersionUID 1L;Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stubPrintWriter out resp.getWriter();// 得到ServletContext对象ServletContext context this.getServletContext();// 得到包含所有初始化参数名的Enumeration对象EnumerationString paramNames context.getInitParameterNames();// 遍历所有的初始化参数名得到相应的参数值打印到控制台out.println(all the paramName and paramValue are following:);// 遍历所有的初始化参数名得到相应的参数值并打印while (paramNames.hasMoreElements()) {String name paramNames.nextElement();String value context.getInitParameter(name);out.println(name : value);out.println(br);}}Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stubsuper.doPost(req, resp);}
}
TestServlet04.java文件
package cn.itcast.servlet;
import java.io.*;import jakarta.servlet.ServletContext;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;public class TestServlet04 extends HttpServlet {/*** */private static final long serialVersionUID 1L;Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stub
// super.doGet(req, resp);ServletContext context this.getServletContext();// 通过setAttribute()方法设置属性值context.setAttribute(data, this servlet save data);}Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stubsuper.doPost(req, resp);}
}
TestServlet05.java文件
package cn.itcast.servlet;
import java.io.IOException;
import java.io.PrintWriter;import jakarta.servlet.ServletContext;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;public class TestServlet05 extends HttpServlet {/*** */private static final long serialVersionUID 1L;Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stub
// super.doGet(req, resp);ServletContext context this.getServletContext();Object object context.getAttribute(data);PrintWriter out resp.getWriter();out.println(object.toString());}Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {// TODO Auto-generated method stubsuper.doPost(req, resp);}
}
SomeServlet.java文件
package com.powernode.servlets;import java.io.IOException;import jakarta.servlet.Servlet;
import jakarta.servlet.ServletConfig;
import jakarta.servlet.ServletContext;
import jakarta.servlet.ServletException;
import jakarta.servlet.ServletRequest;
import jakarta.servlet.ServletResponse;public class SomeServlet implements Servlet {private ServletConfig config;Overridepublic void init(ServletConfig config) throws ServletException {// TODO Auto-generated method stubthis.config config;System.out.println(init);}Overridepublic ServletConfig getServletConfig() {// TODO Auto-generated method stubreturn config;}Overridepublic void service(ServletRequest req, ServletResponse res) throws ServletException, IOException {// TODO Auto-generated method stub
// 获取servlet名称String servletName config.getServletName();System.out.println(获取servlet名称: servletName);// 获取servletContext对象ServletContext servletContext config.getServletContext();System.out.println(获取servletContext对象 servletContext);
// 获取初始化参数String initParameter1 config.getInitParameter(name);System.out.println(name: initParameter1);System.out.println(service);}Overridepublic String getServletInfo() {// TODO Auto-generated method stubreturn null;}Overridepublic void destroy() {// TODO Auto-generated method stubSystem.out.println(destroy());}}
