板瓦工安装wordpress,海南seo排名,安卓开发平台,创网网络前言:我们知道 MyHttpServlet是MyGenericServlet的子类#xff0c;MyHttpServlet会继承父类的方法#xff0c;可是却很少去追问MyHttpServlet中的doGet方法和doPost方法是如何进行判断的#xff0c;本文主要做一个小例子#xff0c;进一步理解HttpServlet。有些代码前文多次… 前言:我们知道 MyHttpServlet是MyGenericServlet的子类MyHttpServlet会继承父类的方法可是却很少去追问MyHttpServlet中的doGet方法和doPost方法是如何进行判断的本文主要做一个小例子进一步理解HttpServlet。有些代码前文多次用到这里不再叙述。 1.项目结构 2.web.xml ?xml version1.0 encodingUTF-8?
web-app xmlns:xsihttp://www.w3.org/2001/XMLSchema-instance xmlnshttp://java.sun.com/xml/ns/javaee xsi:schemaLocationhttp://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd idWebApp_ID version3.0display-namejavaWeb_09/display-namewelcome-file-listwelcome-filelogin.jsp/welcome-file/welcome-file-listservletservlet-namemyHttpServletExtends/servlet-nameservlet-classcom.dao.chu.MyHttpServletExtends/servlet-class/servletservlet-mappingservlet-namemyHttpServletExtends/servlet-nameurl-pattern/myHttpServletExtends/url-pattern/servlet-mapping/web-app 3.login.jsp % page languagejava contentTypetext/html; charsetutf-8pageEncodingutf-8%
!DOCTYPE html PUBLIC -//W3C//DTD HTML 4.01 Transitional//EN http://www.w3.org/TR/html4/loose.dtd
html
head
title登陆页/title
/head
bodyform actionmyHttpServletExtends methodpost用户名input typetext nameuserbrbr密码 input typepassword namepasswordbrbr!-- 一组信息 --interesting:input typecheckbox nameinteresting valuereadingReadinginput typecheckbox nameinteresting valuewritingWritinginput typecheckbox nameinteresting valuefootballFootballinput typecheckbox nameinteresting valuegameGameinput typecheckbox nameinteresting valueshoppingShoppinginput typecheckbox nameinteresting valuepartyPartyinput typecheckbox nameinteresting valueTVTVbrbrinput typesubmit value提交/form/body
/html 4.MyGenericServlet package com.dao.chu;import java.util.Enumeration;import javax.servlet.Servlet;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;/*** * p* Title: MyGenericServlet* /p* p* Description: 自定义MyGenericServlet* /p*/
public abstract class MyGenericServlet implements Servlet, ServletConfig {// ServletConfig对象在init方法执行后赋值private ServletConfig servletConfig;/*** 实现Servlet的方法*/Overridepublic void destroy() {}Overridepublic String getServletInfo() {return ;}// ServletConfig对象的get方法Overridepublic ServletConfig getServletConfig() {return servletConfig;}Overridepublic void init(ServletConfig servletConfig) throws ServletException {this.servletConfig servletConfig;init();}// 空的init函数用来给子类继承防止覆盖init(ServletConfig servletConfig)方法引起的错误public void init() {}//抽象方法必需被子类实现Overridepublic abstract void service(ServletRequest servletRequest,ServletResponse servletResponse);/*** 实现ServletConfig的方法*/Overridepublic String getServletName() {return getServletConfig().getServletName();}Overridepublic ServletContext getServletContext() {return getServletConfig().getServletContext();}Overridepublic String getInitParameter(String paramString) {return getServletConfig().getInitParameter(paramString);}Overridepublic EnumerationString getInitParameterNames() {return getServletConfig().getInitParameterNames();}}5.MyHttpServlet package com.dao.chu;import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** * p* Title: MyHttpServlet* /p* p* Description:自定义 HttpServlet* /p*/
public abstract class MyHttpServlet extends MyGenericServlet {private static final String METHED_GETGET;private static final String METHED_POSTPOST;Overridepublic void service(ServletRequest servletRequest,ServletResponse servletResponse) {try {// 强转类型HttpServletRequest request (HttpServletRequest) servletRequest;HttpServletResponse response (HttpServletResponse) servletResponse;// 调用service(HttpServletRequest,HttpServletResponse)方法service(request, response);} catch (Exception e) {e.printStackTrace();}}protected void service(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) {// 根据请求方式,决定使用的方法String method httpServletRequest.getMethod();if (method.equalsIgnoreCase(METHED_GET)) {doGet(httpServletRequest, httpServletResponse);} else if (method.equalsIgnoreCase(METHED_POST)) {doPost(httpServletRequest, httpServletResponse);}}protected void doPost(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) {}protected void doGet(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) {}}6.MyHttpServletExtends package com.dao.chu;import java.io.IOException;
import java.io.PrintWriter;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** * p* Title: MyHttpServletExtends* /p* p* Description: 继承MyHttpServletExtends的类* /p*/
public class MyHttpServletExtends extends MyHttpServlet {/*** Post请求方式*/Overridepublic void doPost(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) {try {PrintWriter out httpServletResponse.getWriter();out.print(hello Post);} catch (IOException e) {e.printStackTrace();}}/*** Get请求方式*/Overridepublic void doGet(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) {try {PrintWriter out httpServletResponse.getWriter();out.print(hello Get);} catch (IOException e) {e.printStackTrace();}}}7.页面请求提交后可以根据判断的请求方式到相应的方法中执行: 所以HttpServlet中重载了service方法主要作用是根据请求类型调用相应的doXXX方法。 转载于:https://www.cnblogs.com/tongrui/p/6193828.html
