Java 修改服务器以允许多个客户端同时连接

因此，我已经为任务的前一部分创建了一个服务器和一个客户机，但现在我必须扩展/修改服务器，以便它可以同时处理多个客户机。 我知道我必须要做一些事情

Server server1 = new Server();

Thread thread = new Thread(server1);

thread.start();

并使类服务器实现可运行

但是讲师们关于多线程的笔记不是很清楚，我已经在这个问题的这一部分做了很长一段时间的研究，没有找到答案

下面是我一次为一个客户端编写的连接到服务器的代码。 任何帮助都将不胜感激

Server.java

public class Server {

    ArrayList<String> tokens = new ArrayList<String>();

    private Socket s;
    private Scanner in;
    private PrintWriter out;

    public static void main(String[] args) throws IOException {
        ServerSocket server = new ServerSocket(1234);
        Server serverInstance = new Server();
        System.out.println("Server running. Waiting for a client to connect...");
        while (true) {
            serverInstance.s = server.accept();
            System.out.println("Client connected");
            serverInstance.run();
            System.out.println("Client disconnected. Waiting for a new client to connect...");
        }
    }

    public void start() {
        System.out.println("Starting " + threadName);
        if (t == null) {
            t = new Thread(this, threadName);
            t.start();
        }
    }

    public void run() {
        try {
            try {
                in = new Scanner(s.getInputStream());
                out = new PrintWriter(s.getOutputStream());
                doService(); // the actual service
            }
            finally {
                s.close();
            }
        }
        catch (IOException e) {
            System.err.println(e);
        }
    }

    public void doService() throws IOException {
        while (true) {
            if (!in.hasNext())
                return;
            String request = in.next();
            System.out.println("Request received: " + request);
            // (...) test for type of request here (not implemented)
            Request(request);
        }
    }

    public void Request(String request) {

        String amountStr = in.next();
        if (request.startsWith("SUBMIT")) {
            if (tokens.size() < 10) {
                tokens.add(amountStr);
                System.out.println("Token added");
                out.println("OK");
            }
            else {
                System.err.println("Error");
                out.println("Error");
            }
        }
        else if (request.startsWith("REMOVE")) {
            if (tokens.contains(amountStr)) {
                tokens.remove(amountStr);
                System.out.println("Tokens removed");
                out.println("OK");
            }
            else {
                System.err.println("Error");
                out.println("Error");
            }

        }
        else if (request.equals("QUIT")) {
            System.err.println("Program ended");
            out.println("Program ended");
        }

        tokens.sort(null);
        System.out.println(tokens);
        out.flush();
    }
}

---

您试图复制的是RMI几十年来一直在做的事情。Java是开源的，因此您可以了解RMI的工作原理并从中学习。您还可以在internet上查找无数带有/不带RMI的多线程服务器示例

阅读一篇教程（例如），然后尝试一些东西。讲师的笔记并不是唯一可以免费获得多线程信息的地方。整个网络都在您的掌控之中。您是否尝试过

executorservice

，

semaphore

？通常，您需要一个线程来侦听新连接，在连接到达时生成新线程或任务。

public class Client {
    public static void main(String[] args) throws IOException {
         Socket s = new Socket("localhost", 1234);
         InputStream instream = s.getInputStream();
         OutputStream outstream = s.getOutputStream();
         Scanner in = new Scanner(instream);
         PrintWriter out = new PrintWriter(outstream);
         String request = "SUBMIT hello \n";
         out.print(request);
         out.flush();
         String response = in.nextLine();
         System.out.println("Token: " + response);
         s.close();
    }
}