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
             }
         }
     }

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