• hello2源码解析


    GreetingServlet.java源码:

    @WebServlet("/greeting")    //以@WebServlet注释开头,表示在根目录下使用/greeting来访问
      public class GreetingServlet extends HttpServlet

    {
         @Override
          public void doGet(HttpServletRequest request,    //重写了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8192
             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("<html lang="en">"
                         + "<head><title>Servlet Hello</title></head>");
                
                      //使用println属性,向html页面输出html标签
                
                 out.println("<body  bgcolor="#ffffff">"
                         + "<img src="resources/images/duke.waving.gif" "
                        + "alt="Duke waving his hand">"
                         + "<form method="get">"
                         + "<h2>Hello, my name is Duke. What‘s yours?</h2>"
                         + "<input title="My name is: " type="text" "
                         + "name="username" size="25"/>"
                        + "<p></p>"
                         + "<input type="submit" value="Submit"/>"
                         + "<input type="reset" value="Reset"/>"
                         + "</form>");

                         //使用println属性,向html页面输出html标签
                
              
                 String username = request.getParameter("username");   //使用一个字符串username来获取,第一个input标签内的username的值
                 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) {
                         
                         dispatcher.include(request, response);//整合request, response然后跳转
                     }
                 }
                 
                 out.println("</body></html>");//使用println属性,向html页面输出html标签
             }
         }

    ResponseServlet.java源码:

    @WebServlet("/response")    //以@WebServlet注释开头,表示在根目录下使用/response来访问。
      public class ResponseServlet extends HttpServlet {
     
          @Override
         public void doGet(HttpServletRequest request,    //重写了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
                 String username = request.getParameter("username");        //接收来自greting页面请求中的input标签中输入的username             if (username != null && username.length() > 0){

                     out.println("<h2>Hello, " + username + "!</h2>");//使用println属性,向html页面输出html标签
                 }
             }
         }

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  • 原文地址:https://www.cnblogs.com/railgun1/p/10836089.html
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