如何关闭带有特定消息的套接字？

Question

I've stabilished a socket connection between a Client and a Server, but now I'm trying to get the Server to close the connection whenever he receives a specific message ("FIM"), so far I've had no luck. I keep sending the message "FIM" and the connection doesn't close

Heres the code:

class Cliente {
    public static void main(String argv[]) throws UnknownHostException, IOException {
        InetAddress ip = InetAddress.getLocalHost();
        String hostName = ip.getHostName();
        Socket meuSocket = new Socket(hostName, 6789);

        PrintWriter saida = new PrintWriter(meuSocket.getOutputStream(), true);
        BufferedReader digitado = new BufferedReader(new InputStreamReader(System.in));

        while (meuSocket.isConnected()) {
            String mensagemParaServidor = digitado.readLine();
            if (mensagemParaServidor == "FIM") {
                meuSocket.close();
                break;
            }
            saida.println(mensagemParaServidor);
        }
    }
}

---

class Servidor {
    public static final int PORT = 6789;

    public static void main(String argv[]) throws IOException {
        new Servidor().rodarServidor();
    }

    public void rodarServidor() throws IOException {
        ServerSocket serverSocket = new ServerSocket(PORT);
        System.out.println("Servidor pronto");

        while (true) {
            Socket meuSocket = serverSocket.accept();
            new ServerThread(meuSocket).start();
        }
    }

}

---

public class ServerThread extends Thread {
    Socket meuSocket;

    ServerThread(Socket meuSocket) {
        this.meuSocket = meuSocket;
    }

    public void run() {

        try {
            String mensagemRecebida = null;
            BufferedReader entrada = new BufferedReader(new InputStreamReader(meuSocket.getInputStream()));

            while (((mensagemRecebida = entrada.readLine()) != null)
                || ((mensagemRecebida = entrada.readLine()) != "FIM")) {
                System.out.println("Cliente enviou: " + mensagemRecebida);
                DataOutputStream saida = new DataOutputStream(meuSocket.getOutputStream());
                saida.writeBytes("Obrigado!");
            }
            System.out.println("Fechando servidor");
            meuSocket.close();

        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

Thanks!

Answer 1

Never compare stirng with == use equals instead.

It's bad idea just use readLine. Better pack your string in some kind of message and send whole message. So the other side can figure out the end and the start of the message. For example the first byte can be the next message length. Also you are calling readLine twice in ServerThread