Java套接字，接收空文件

Question

我正在創建一個應用程序來從客戶端發送文件並通過套接字通過服務器接收它。

當我在我的PC（客戶端 - 服務器在同一臺PC上）測試應用程序時，一切運行正常，但是當我在不同的PC上測試應用程序時，出現以下錯誤。

1. 第一次嘗試：沒有發生，沒有錯誤，沒有發送文件。
2. 第二次嘗試：Java引發了一個已經在使用中的Ip錯誤，但我在服務器PC上收到了該文件，但它沒有數據。

下面是客戶端的代碼：

public class FileSender { 

    public static void main(String[] args) { 
     // TODO Auto-generated method stub 
FileSender nioClient = new FileSender(); 
SocketChannel socketChannel = nioClient.createChannel(); 
try { 
    nioClient.sendFile(socketChannel); 
} catch (FileNotFoundException | InterruptedException e) { 
    // TODO Auto-generated catch block 
    e.printStackTrace(); 
} 
//SocketChannel socketChannel = nioClient.createc 
    } 
public SocketChannel createChannel(){ 

    SocketChannel socketChannel = null; 

    try { 
     socketChannel = SocketChannel.open(); 
     SocketAddress socketAddress = new InetSocketAddress("xx.xxx.xxx.x", 10002); 
     socketChannel.connect(socketAddress); 
     System.out.println("Connected..Now Sending the File"); 
    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
return socketChannel; 
} 

public void sendFile(SocketChannel socketChannel) throws FileNotFoundException, InterruptedException{ 

    RandomAccessFile afile = null; 

    try { 
     File file = new File("/home/dionisio/Imágenes/ImagenesOriginalesPrueba/flowers.jpg"); 
     afile = new RandomAccessFile(file, "r"); 
     FileChannel inChannel = afile.getChannel(); 
     ByteBuffer buffer = ByteBuffer.allocate(8192); 
     while (inChannel.read(buffer) != -1) { 
      buffer.flip(); 
      socketChannel.write(buffer); 
      buffer.clear();  
     } 
     socketChannel.close(); 
     afile.close(); 
    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 
} 

} 

服務器代碼

public class FileReceiver { 

    public static void main(String[] args) { 
     // TODO Auto-generated method stub 
FileReceiver nioServer = new FileReceiver(); 
SocketChannel socketChannel = nioServer.createServerSocketChannel(); 
nioServer.readFileFromSocket(socketChannel); 
    } 

    private SocketChannel createServerSocketChannel() { 
     // TODO Auto-generated method stub 
     ServerSocketChannel serverSocketChannel = null; 
     SocketChannel socketChannel = null; 

     try { 
      serverSocketChannel = ServerSocketChannel.open(); 
      serverSocketChannel.socket().bind(new InetSocketAddress(10002)); 
      socketChannel = serverSocketChannel.accept(); 
      System.out.println("Connection Stablished..."+socketChannel.getRemoteAddress()); 

     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
     return socketChannel; 
    } 


    private void readFileFromSocket(SocketChannel socketChannel) { 
     // TODO Auto-generated method stub 

    RandomAccessFile afile = null; 

    try { 
     afile = new RandomAccessFile("/home/dionisio/Imágenes/imagenesCopiaPrueba/flowersCopia.jpg","rw"); 
     ByteBuffer buffer = ByteBuffer.allocate(8192); 
     FileChannel fileChannel = afile.getChannel(); 
     while (socketChannel.read(buffer)>0) { 
      buffer.flip(); 
      fileChannel.write(buffer); 
      buffer.clear(); 
     } 
     Thread.sleep(1000); 
     fileChannel.close(); 
     System.out.println("End of file reached...Closing Channel"); 
     socketChannel.close(); 
    } catch (FileNotFoundException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } catch (IOException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } catch (InterruptedException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } 


    } 


} 

Answer 1

你讀循環是不正確的。他們應該是這樣的形式：

while (in.read(buffer) > 0 || buffer.position() > 0) 
{ 
    buffer.flip(); 
    out.write(buffer); 
    buffer.compact(); 
} 

否則您可能會丟失數據。

NB

• Java不 '已在使用IP' 拋出一個錯誤。準確。
• 你不需要睡覺。不要將睡眠添加到網絡代碼。它沒有解決任何問題。

Answer 2

我的家人感謝您的回覆，現在我知道我的錯誤是什麼，我在我的客戶端應用程序上輸入了錯誤的IP地址。

然而EJP我會採取你的建議，以更好的字節檢查時，寫一個頻道。