java - 无法通过互联网连接到 ServerSocket

Question

大家好，我创建了一个简单的聊天室应用程序，但无法连接到服务器来发送和接收数据，这是我的代码的一部分:

服务器端:

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.regex.Pattern;

public class Listener {

public static void start() {
    try {
        final ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        serverSocketChannel.configureBlocking(true);
        serverSocketChannel.socket().bind(new InetSocketAddress(GetConfigs.getServerListenerPort()));
        final List<Operator> operators = new ArrayList<>();
        final int nOperators = 64;
        for (int i = 0; i < nOperators; i++) {
            operators.add(i, new Operator());
        }
        final int parallelism = Runtime.getRuntime().availableProcessors();
        ForkJoinPool pool = new ForkJoinPool(parallelism);
        pool.submit(() -> new Thread(() -> {
            int i = 0;
            while (true) {
                try {
                    operators.get(i).newOperation(serverSocketChannel.accept());
                    i++;
                    if (i == nOperators) {
                        i = 0;
                    }
                } catch (IOException ignored) {
                }
            }
        })).fork().invoke().start();
    } catch (IOException e) {
        Logging.log.error(e);
    }
}

客户端:

import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.Socket;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.regex.Pattern;

public class ConnectServer {

private static final String SERVER_ADDRESS = GetConfigs.getServerIPAddress();
private static final int SERVER_LISTENER_PORT = GetConfigs.getServerListenerPort();

private StringBuilder result = new StringBuilder();

private void connect() {
    result.delete(0, result.length());
    try {
        SocketChannel socketChannel = SocketChannel.open();
        socketChannel.configureBlocking(true);
        if (socketChannel.connect(new InetSocketAddress(InetAddress.getByName(SERVER_ADDRESS), SERVER_LISTENER_PORT))) {
            DataOutputStream dos = new DataOutputStream(socketChannel.socket().getOutputStream());
            DataInputStream dis = new DataInputStream(socketChannel.socket().getInputStream());
            dos.writeUTF("...");
            result.append(String.valueOf(dis.readUTF()));
            dos.close();
            dis.close();
            socketChannel.close();
        }
    } catch (IOException ex) {
        //...
    }
}

}

它确实可以在 LAN 连接上工作。

请帮助我...

Answer 1

这是一个简单的测试。通过 SSH 连接到 LAN 之外的计算机，即您无法连接的计算机。尝试两件事:

ping <ip address you connect to>

和

telnet <ip address you connect to> <port you connect to>

如果 ping 失败，则您可能正在使用“内部”IP 地址，例如 192.168.x.y(或其他类似地址)。尝试使用http://www.whatismyip.com/从您的服务器计算机。

如果 ping 成功而 telnet 失败，则可能存在防火墙问题:请在路由器上设置端口转发，在防火墙上戳一个洞，然后执行其他需要的操作。到底需要什么取决于您的具体设置。