手工编写第一个Servlet

xiaoxiao2021-02-28  9

一 步骤 1、继承HttpServlet 2、重写doGet()或者doPost()方法 3、在web.xml中注册Servlet   二 HttpServlet类继承图     三 实例 1、创建MyFirstServletDemo web project.   2、编辑index.jsp <%@ page language = "java" import = "java.util.*"   contentType = "text/html; charset=utf-8" %> <% String path = request.getContextPath(); String basePath = request.getScheme()+ "://" +request.getServerName()+ ":" +request.getServerPort()+path+ "/" ; %>   <! DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> < html >   < head >     < base href = " <%= basePath %> " >         < title > My JSP 'index.jsp' starting page </ title >          < meta http-equiv = "pragma" content = "no-cache" >          < meta http-equiv = "cache-control" content = "no-cache" >          < meta http-equiv = "expires" content = "0" >              < meta http-equiv = "keywords" content = "keyword1,keyword2,keyword3" >          < meta http-equiv = "description" content = "This is my page" >          <!--         <link rel =" stylesheet " type="text/ css " href ="styles.css">         -->   </ head >     < body >     < h1 > 第一个 Servlet 小例子 </ h1 >     < a href = "servlet/HelloServlet" > Get方式请求HelloServlet </ a >      < form action = "servlet/HelloServlet" method = "post" >                  < input type = "submit" value = "Post方式请求HelloServlet" >      </ form >   </ body > </ html > 3、编写HelloServlet package 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;   //继承于HttpServlet public class HelloServlet extends HttpServlet {            @Override          protected void doGet(HttpServletRequest request, HttpServletResponse response)                          throws ServletException, IOException {                  // TODO Auto-generated method stub                 System. out .println( "处理get()请求..." );                 PrintWriter out = response.getWriter();                 response.setContentType( "text/html; charset=utf-8" );                 out.println( "<strong>Hello Servlet!</strong><br>" );         }            @Override          protected void doPost(HttpServletRequest request, HttpServletResponse response)                          throws ServletException, IOException {                 System. out .println( "处理post()请求..." );                 PrintWriter out = response.getWriter();                 response.setContentType( "text/html; charset=utf-8" );                 out.println( "<strong>Hello Servlet!</strong><br>" );         }   } 4、编写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" ; >   < display-name ></ display-name >      < welcome-file-list >     < welcome-file > index.jsp </ welcome-file >   </ welcome-file-list >   < servlet >          < servlet-name > HelloServlet </ servlet-name >          < servlet-class > servlet.HelloServlet </ servlet-class >   </ servlet >   < servlet-mapping >          < servlet-name > HelloServlet </ servlet-name >          < url-pattern > / servlet /HelloServlet </ url-pattern >   </ servlet-mapping > </ web-app >   四 运行结果

 

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