hello2应用程序是一个web模块，它使用Java Servlet技术来显示问候和响应。此应用程序的源代码位于 _tut-install_/examples/web/servlet/hello2/目录中。

GreetingServlet.java

/** * Copyright (c) 2014 Oracle and/or its affiliates. All rights reserved. * * You may not modify, use, reproduce, or distribute this software except in * compliance with  the terms of the License at: * https://github.com/javaee/tutorial-examples/LICENSE.txt */package javaeetutorial.hello2;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@WebServlet("/greeting")    //以@WebServlet注释开头，注释指定相对于上下文根的URL模式，即在根目录下使用/greeting来访问  public class GreetingServlet extends HttpServlet {        @Override      public void doGet(HttpServletRequest request,    //该servlet重写该doGet方法，实现GET HTTP方法              HttpServletResponse response)              throws ServletException, IOException {           response.setContentType("text/html");    //指定响应页面的类型为html        response.setBufferSize(8192);    //指定缓冲区大小         try (PrintWriter out = response.getWriter()) {    //实例化对象out,作为向html页面输出的对象                          //使用println属性，向html页面输出html标签,这里输出的是：             //             //                //                     //                out.println(""                     + "");                          //使用println属性，向html页面输出html标签,这里输出的是：             //             //                 //    
     
                   //        
      
Hello, my name is Duke. What‘s yours?
             //        
                   //        
      
             //        
                   //        
                   //    
     
)                          out.println(""                     + ""                     + "
     
      "                     + "
      
Hello, my name is Duke. What‘s yours?
"                     + "
      "                    + "
      
"                     + "
      "                     + "
      "                     + "
     
");                          //使用一个字符串username来获取，第一个input标签内的username的值             String username = request.getParameter("username");             if (username != null && username.length() > 0) {                 RequestDispatcher dispatcher =                         getServletContext().getRequestDispatcher("/response");                         //指定要跳转的页面相对于上下文根的URL模式为/response                                  if (dispatcher != null) {                     //整合request, response然后跳转                     dispatcher.include(request, response);                 }             }             //使用println属性，向html页面输出html标签,这里输出的是：             //                 //             out.println("");         }     }      @Override    public String getServletInfo() {         return "The Hello servlet says hello.";      } }

 

 ResponseServlet.java

/** * Copyright (c) 2014 Oracle and/or its affiliates. All rights reserved. * * You may not modify, use, reproduce, or distribute this software except in * compliance with  the terms of the License at: * https://github.com/javaee/tutorial-examples/LICENSE.txt */package javaeetutorial.hello2;import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@WebServlet("/response")    //以@WebServlet注释开头，注释指定相对于上下文根的URL模式，                              //即在根目录下使用/response来访问,这里作为greting页面的响应页面来实现访问  public class ResponseServlet extends HttpServlet {        @Override     public void doGet(HttpServletRequest request,    该servlet重写该doGet方法，实现GET HTTP方法             HttpServletResponse response)              throws ServletException, IOException {          try (PrintWriter out = response.getWriter()) {        //实例化对象out,作为向html页面输出的对象             //接收来自greting页面请求中的input标签中输入的username             String username = request.getParameter("username");                     if (username != null && username.length() > 0) {               //使用println属性，向html页面输出html标签,这里输出的是：                 //
Hello,XXX(前面输入的username的值)!
                 out.println("
Hello, " + username + "!
");             }         }     }      @Override     public String getServletInfo() {         return "The Response servlet says hello.";      } }