整数不会增加？

Question

好吧,所以我正在进行客户端/服务器测试,我将Integer playerID传递给一个线程,它将int值赋给一个简单的Player对象,而不是将playerID增加1.

 public static void main(String[] args) throws IOException {

        Vector<Player> player = new Vector<Player>();

        SlickServer ss = new SlickServer();
        ss.setVisible(true);

        ServerSocket serverSocket = new ServerSocket(4444);
        boolean listening = true;

        Integer playerID = new Integer(0);

        while(listening){
            ss.textArea.append("Waiting to connect with player: " + playerID.intValue()  + "\n");
            new ClientThread(serverSocket.accept(), player, playerID, ss.textArea).start();
            ss.textArea.append("Waiting to connect with player: " + playerID.intValue() + "\n");
        }

        serverSocket.close();
        System.exit(0);
    }

这是在线程中增加它的地方:

public ClientThread(Socket acceptedSocket, Vector<Player> players, Integer playerID, JTextArea textArea){
        super("ClientThread");
        this.acceptedSocket = acceptedSocket;
        this.players = players;
        players.add(new Player(50,50, playerID.intValue()));

        if(players != null)
            System.out.println("Not Null: " + players.size());

        boolean b = false;
        for(int i = 0; i < players.size(); i++){
            if(!b){
                if(players.get(i).id == playerID){
                    me = players.get(i);
                    b = true;
                }
            }
        }

        playerID = new Integer(playerID.intValue() + 1);
        this.textArea = textArea;
    }

Answer 1

new IntegerInteger在客户端线程方法中创建一个全新的实例,调用者无法使用它.

但是,您需要考虑主线程和客户端线程之间的同步.这可以使用synchronized非平凡对象的语句或类java.util.concurrent.atomic.AtomicInteger的整数来实现,如下所示:

AtomicInteger playerID = new AtomicInteger(0);
while (listening) {
  ss.textArea.append("Waiting to connect with player: " + playerID.get()  + "\n");
  new ClientThread(serverSocket.accept(), player, playerID, ss.textArea).start();
  ss.textArea.append("Waiting to connect with player: " + playerID.get() + "\n");
}

class ClientThread {
  public ClientThread(Socket acceptedSocket, Vector<Player> players, AtomicInteger playerID, JTextArea textArea) {
    // etc.
    playerID.incrementAndGet();
    // etc.
  }
}

您需要考虑如何在并发执行的线程之间共享数据.这也适用于Vector<Player>和JTextArea参数.您应该根据需要使用语句包装对players和textArea对象的访问synchronize.