CODEWITHSUNDEEP
javamultithreadingsocketswebserver
Tony
Tony

Reputation: 3805

Multithread java webserver

I'm coding a server and this is how it looks now:

import java.net.ServerSocket;
import java.net.Socket;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.InputStreamReader;
import java.io.BufferedReader;

public class HttpServer {

    public static void main(String[] args) throws Throwable {
        //http://localhost:3000
        ServerSocket ss = new ServerSocket(3000);

        while (true) {
            //Waiting for socket
            Socket s = ss.accept();
            System.out.println("Client accepted");
            //The main process
            new SocketProcessor(s,ss).start();
        }
    }

    private static class SocketProcessor implements Runnable {
        private Thread t;
        private Socket s;
        private ServerSocket ss;
        private InputStream is;
        private OutputStream os;

        private SocketProcessor(Socket s,ServerSocket ss) throws Throwable {
            t = new Thread(this, "Server Thread");
            this.ss=ss;
            this.s = s;
            this.is = s.getInputStream();
            this.os = s.getOutputStream();
        }

        public void run() {
            try {
                readInputHeaders(); 
                Thread.sleep(10000);
                writeResponse("<html><body><h1>Hello</h1></body></html>");


            } catch (Throwable t) {
                /*do nothing*/
            } finally {
                try {
                    s.close();
                } catch (Throwable t) {

                }
            }
            System.out.println("Client processing finished");
        }


        public void start()
        {
            t.start();
        }

        private void writeResponse(String s) throws Throwable {
            String response = "HTTP/1.1 200 OK\r\n" +
                    "Server: Server\r\n" +
                    "Content-Type: text/html\r\n" +
                    "Content-Length: " + s.length() + "\r\n" +
                    "Connection: close\r\n\r\n";
            String result = response + s;
            os.write(result.getBytes());
            os.flush();
        }

        private void readInputHeaders() throws Throwable {
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            while(true) {
                String s = br.readLine();
                System.out.println(s);
                if(s == null || s.trim().length() == 0) {
                    break;
                }
            }
        }
    }
}

Doesn't this 

while (true) {
                //Waiting for socket
                Socket s = ss.accept();
                System.out.println("Client accepted");
                //The main process
                new SocketProcessor(s,ss).start();
            }

make webserver multithreaded? I was trying to run http://localhost:3000 from 2 different tabs in my browser. As you can see, I make my server wait for 10 seconds before response, so every page should take equal time. But no, it's not: first opened page takes 10, and 2nd - 20.

What's wrong?

UPD: I have thoughts, that ss.accept(); freezes server.

Upvotes: 1

Views: 174

Answers (2)

J.J
J.J

Reputation: 643

Oh I see what is going on, are you opening two tabs in a single browser and connecting to your program? So it might be your browser that is serializing your requests.

If you open two browsers and make a request, your program will work as intended.

Upvotes: 1

amarseillan
amarseillan

Reputation: 462

Tried on different browsers and this doesn't happen in them. You are using chrome as I was? It may be chrome doing some strange stuff for same requests.

Note that I do

http://localhost:3000

and

http://localhost:3000?diff=true

and I get both of them in 10 seconds instead of 10 and 20 for the same request.

I would still love from someone to explain this, but maybe thats another question.

Upvotes: 2

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