hello2分析

public class GreetingServlet extends HttpServlet {

//使用doget方法，传入request和response两个参数，返回text/html且最大字节数为8192

@Override
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {

response.setContentType("text/html");
response.setBufferSize(8192);

//向客户端浏览器页面输入前端数据
try (PrintWriter out = response.getWriter()) {
out.println(""
+ "");

// then write the data of the response
out.println(""
+ " + "alt=\"Duke waving his hand\">"
+ ""
+ "

Hello, my name is Duke. What‘s yours?

String username = request.getParameter("username");
if (username != null && username.length() > 0) {
RequestDispatcher dispatcher =
getServletContext().getRequestDispatcher("/response");//若username不为空，则使用dispatcher接收客户端请求并发送到服务器

if (dispatcher != null) {
dispatcher.include(request, response);//若客户端请求不为空，则响应资源
}
}
out.println("");
}
}

@Override
public String getServletInfo() {
return "The Hello servlet says hello.";

}
}

@WebServlet("/response")
public class ResponseServlet extends HttpServlet {

@Override
public void doGet(HttpServletRequest request,
HttpServletResponse response)
throws ServletException, IOException {
try (PrintWriter out = response.getWriter()) {

//对用户输入的信息进行判别，并通过responseServlet进行处理
String username = request.getParameter("username");
if (username != null && username.length() > 0) {
out.println("

Hello, " + username + "!

@Override
public String getServletInfo() {
return "The Response servlet says hello.";