為什么服務器和客戶端不能一起啟動？

相關代碼：

 @Test
    public void serverTest() throws IOException {
        GameServer server = new GameServer();
        server.start(9000);
        GameClient client1 = new GameClient();
        GameClient client2 = new GameClient();
        client1.startConnection("localhost", 9000);
        client2.startConnection("localhost", 9000);
        client1.sendMessage("Hey I am client 1");
        client2.sendMessage("Hey I am client 2");

    }

public class GameServer {
    private ServerSocket serverSocket;

    public void start(int port) throws IOException {
        System.out.println("Server started !!!");
        serverSocket = new ServerSocket(port);
        while (true) {
            new Thread(new GameClientHandler(serverSocket.accept())).start();
        }
    }

    public void stop() throws IOException {
        serverSocket.close();
    }


   private static class GameClientHandler implements Runnable {
        private Socket clientSocket;
        private PrintWriter out;
        private BufferedReader in;

        public GameClientHandler(Socket socket) {
            this.clientSocket = socket;
        }

        @Override
        public void run() {
            System.out.println(Thread.currentThread().getName());
            try {
                out = new PrintWriter(clientSocket.getOutputStream(), true);
                in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

                String inputLine = in.readLine();
                while ((inputLine = in.readLine()) != null){
                    System.out.print(inputLine);
                }


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



            try {
                in.close();
                out.close();
                clientSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }

Why can't the server and client be started together in the @Test? I think it gets stuck in the infinite while loop but at the same time, shouldn't there be context switching with the new threads started after accepting the connection?

I expected at least the name of the 2 new threads to be printed but it doesn't happen.

uj5u.com熱心網友回復：

讓我們仔細查看您的測驗代碼：

    GameServer server = new GameServer();

好的，這一行創建了一個服務器，測驗執行緒準備好執行下一行

    server.start(9000);

好的，測驗執行緒啟動服務器，并準備在start方法回傳時執行下一行。

發生了什么start：

    System.out.println("Server started !!!");

好的，您應該會看到該訊息

    serverSocket = new ServerSocket(port);

好的，你已經創建了一個 ServerSocket

    while (true) {
        new Thread(new GameClientHandler(serverSocket.accept())).start();
    }

好的，您等待連接（at serverSocket.accept()），一旦您獲得連接，就會創建一個新執行緒來處理它，然后再次回圈。

但此時，測驗執行緒正在等待，永遠不會去下一行開始第一個連接。除非有其他東西（可能是另一個執行緒）啟動那些該死的連接，否則它會一直卡住。

uj5u.com熱心網友回復：

該方法GameServer.start只會回傳例外。那是因為你有 while 回圈。

因此，您的測驗執行將啟動服務器并等待有人打開連接，但這從未發生過。

標籤：java multithreading

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