CODEWITHSUNDEEP
javaamazon-web-servicesamazon-ec2client-server
vrealwavy
vrealwavy

Reputation: 27

Running a live Java Server on Amazon AWS

I am developing a Client-Server application with several other programmers, in Java. At this point in time I do not want to be running the code locally. I want to be able to connect to the Server from any machine.

I wrote a test server and test client, just to make sure that things are working properly. But they are not. I am using Amazon AWS EC2 Linux that comes with Java. I am able to compile and run my Server after I SSH into the EC2, but the Client on my local disk is just not connecting. Here is the code.

// Code found online (https://cs.lmu.edu/~ray/notes/javanetexamples/)
import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.Executors;
import java.util.concurrent.ExecutorService;

public class TestServer {

    public static void main(String[] args) throws Exception {
        try (ServerSocket listener = new ServerSocket(50000)) {
            System.out.println("The capitalization server is running...");
            System.out.println(listener.getInetAddress());
            ExecutorService pool = Executors.newFixedThreadPool(20);
            while (true) {
                pool.execute(new Capitalizer(listener.accept()));
            }
        }
    }

    private static class Capitalizer implements Runnable {
        private Socket socket;

        Capitalizer(Socket socket) {
            this.socket = socket;
        }

        @Override
        public void run() {
            System.out.println("Connected: " + socket);
            try {
                Scanner in = new Scanner(socket.getInputStream());
                PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
                while (in.hasNextLine()) {
                    out.println(in.nextLine().toUpperCase());
                }
            } catch (Exception e) {
                System.out.println("Error:" + socket);
            } finally {
                try { socket.close(); } catch (IOException e) {}
                System.out.println("Closed: " + socket);
            }
        }
    }
}


// Code found online (https://cs.lmu.edu/~ray/notes/javanetexamples/)
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;

public class TestClient {
    public static void main(String[] args) throws Exception {
        try (Socket socket = new Socket("ADDRESS HERE", 50000)) {
            System.out.println("Enter lines of text then Ctrl+D or Ctrl+C to quit");
            Scanner scanner = new Scanner(System.in);
            Scanner in = new Scanner(socket.getInputStream());
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
            while (scanner.hasNextLine()) {
                out.println(scanner.nextLine());
                System.out.println(in.nextLine());
            }
        }
    }
}

In place of "ADDRESS HERE" in the Client, I have tried the private IP and public IP of my Amazon EC2 instance. I have also tried the public DNS name. Nothing seems to work. There is just no connection from the Client to the Server. In fact, "Enter lines of text then Ctrl+D or Ctrl+C to quit" never prints.

All help is appreciated. Thank you.

Upvotes: 1

Views: 263

Answers (2)

Kum
Kum

Reputation: 333

Allow your IP address to send request to the EC2. For this, you need to go to your Security Group and add your IP there. Follow these steps-

  1. GO to your AWS console.
  2. Click on EC2, then under Resources you will find Security Groups.
  3. Select your security group.
  4. Follow the steps in the given image.

steps to follow

Upvotes: 2

nickolay.laptev
nickolay.laptev

Reputation: 2565

Since you're able to connect to EC2 instance via SSH, your Security Group allows this.
Now you need to allow requests from the client in this Security Group. You will either need to provide a concrete IP, IP range or allow all IPs (not recommended) in the group.
You can find how to do this here.

Upvotes: 1

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