Question

这一定很容易但我显然缺少一些基本的理解。我有简单的客户端服务器应用程序

服务器：的

public class GameServer{
   private Socket clientSocket;
   private ServerSocket serverSocket;
   private ArrayList<ObjectOutputStream> oosPlayers=new ArrayList<ObjectOutputStream>();   

   public static void main(String args[]){
       GameServer server = new GameServer();
       server.startGame();
   }   

   public void startGame(){  
      try{
         serverSocket = new ServerSocket(10008);  
         System.out.println("Server started at:" + serverSocket);
         while(true){
             System.out.println("Server: Waiting for client requests...");
             clientSocket=serverSocket.accept();
             System.out.println("Server: Client connection accepted at:"+clientSocket);
             //remember player's output stream
             oosPlayers.add(new ObjectOutputStream(clientSocket.getOutputStream()));
             //read data from clients 
             Thread receiverThread = new Thread(new DataReceiver());
             receiverThread.start();
         }
      }
      catch(IOException ex){
          System.out.println(ex.getMessage());
      }
   }
   public class DataReceiver implements Runnable{
       public void run(){
           try{
               String mess;
               ObjectInputStream ois = new ObjectInputStream(clientSocket.getInputStream());
               while((mess=(String)ois.readObject()) != null){                         
                   System.out.println("Server: "+mess);
                   send();
               }
           }
           catch(Exception ex){ System.out.println(ex.getMessage()); }
       }
       public void send(){
           for (ObjectOutputStream oos : oosPlayers){
               try{
                   oos.writeObject(new String("There is "+oosPlayers.size()+" player(s) at the board"));                   
                   oos.flush();
               }
               catch(Exception ex){ System.out.println(ex.getMessage()); }  
           }
       }
   }        
}

客户端：的

public class GameClient implements ActionListener{
   private Socket socket;
   private ObjectInputStream  ois;
   private ObjectOutputStream oos;
   private JButton button;

   public static void main(String args[]){
       GameClient client = new GameClient();  
       client.drawBoard();
   }
   public void drawBoard(){
       JFrame frame = new JFrame("A game");
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       button = new JButton("Send");
       button.addActionListener(this);
       configureConnection();
       Thread receiverThread = new Thread(new DataReceiver());
       receiverThread.start();

       frame.getContentPane().add(new JPanel().add(button));
       frame.setSize(200,200);
       frame.setVisible(true);
   }   
   public void configureConnection(){
       try{
           socket = new Socket("127.0.0.1", 10008);
           ois = new ObjectInputStream(socket.getInputStream());
           oos = new ObjectOutputStream(socket.getOutputStream());
       }
       catch(Exception ex) { System.out.println(ex.getMessage()); }
   }   

   public void actionPerformed(ActionEvent ev){
       if (ev.getSource()==button){
          try{
              oos.writeObject(new String("Some data from client"));
              oos.flush();
          }
          catch(Exception ex){ System.out.println(ex.getMessage()); }         
       }
   }   

   public class DataReceiver implements Runnable{
       public void run(){
           try{
               String mess;
               while((mess=(String)ois.readObject())!= null){                  
                   System.out.println("Client:"+mess);
               }
           }
           catch(Exception ex){ System.out.println(ex.getMessage()); }
       }
   }   
}

我的问题与双方的 receiverThread 有关。当我从 ObjectInputStream （在RUN方法中）读取期间使用WHILE时，服务器会侦听客户端请求并将它们正确地分派给所有 ObjectOutputStream 。如果我将 WHILE 更改为 IF ，则每个客户端仅从服务器读取（和发送）一次数据。这同样适用于客户的WHILE / IF。

我的理解是，当我运行 receiverThread 时，它会以某种方式停止WHILE处的线程并继续读取输入流，而使用IF让线程完成（从而停止读取过程）。怎么可能虽然WHILE条件不满足，即最初（没有客户端连接），它会使 receiverThread 保持活着状态。在receiverThread已经读取数据并且流中没有任何内容之后也会发生同样的情况。

会对这个基本问题有所解释。

此致马尔钦

Answer 1

如果您在run()方法中改变if，则只读取一个对象并退出。如果您的客户端 - 服务器协议非常简单，例如它们每个会话只发送一个对象，两个版本都相同。否则系统将无法正常工作：所有其他对象将无法到达。

Java：客户端 - 服务器app.-在ObjectInputStream读取线程上的WHILE

1 个答案: