如何在Java中的服务器中侦听和生成客户端响应？

Question

This is my server side code in java listening on port 1880 and making http client request from browser/client.java code in localhost which gives connection refused error.I copied that server code from a webpage.I am not sure what exactly this code is doing.

import com.sun.net.httpserver.HttpExchange;
import com.sun.net.httpserver.HttpHandler;
import com.sun.net.httpserver.HttpServer;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
public class ServerHandlingHttpRequest {
   public void start() throws IOException
    {
                InetSocketAddress addr=new InetSocketAddress(1880);
                System.out.println(addr.getPort());
                System.out.println(addr.getAddress());
                System.out.println(addr.getHostName());
                System.out.println(addr.toString());

                HttpServer server=HttpServer.create(addr,0);
                server.createContext("/", new MyHandler());
                server.setExecutor(null);
                server.start();
                System.out.println("Server Listening");
                System.out.println(server.getAddress());
                server.stop(60);
        }
      class MyHandler implements HttpHandler {
    public void handle(HttpExchange t) throws IOException {
        System.out.println("Request Arrived");
        String response = "This is the response";
        t.sendResponseHeaders(200, response.length());
        OutputStream os = t.getResponseBody();
        os.write(response.getBytes());
        os.close();
    }
}
      public static void main(String[] args) throws IOException
    {
          ServerHandlingHttpRequest w=new ServerHandlingHttpRequest();
          w.start();
     }
    }

Answer 1

That code simply starts listening to the port that you have specified, as an HTTP listener. Which means, any HTTP Request that might come into that port will be intercepted by your program. And when it intercepts, it looks for the context path that you have configured to handle the response to the request.

So, when you run this program, it starts listening at port 1880. When a URL http://localhost:1880/ is hit, it will be intercepted by the handler, MyHandler. The response will be written to the OutputStream which will send back the request back to the client.

One of the problems that I see is that you are stopping the server after printing some statements, while the example that you have refered is not doing so. May be, remove server.stop(60) statement and check whether the issue still persists.