Java套接字，接收空文件

Question

我正在创建一个应用程序来从客户端发送文件并通过套接字通过服务器接收它。

当我在我的PC（客户端 - 服务器在同一台PC上）测试应用程序时，一切运行正常，但是当我在不同的PC上测试应用程序时，出现以下错误。

1. 第一次尝试：没有发生，没有错误，没有发送文件。
2. 第二次尝试：Java引发了一个已经在使用中的Ip错误，但我在服务器PC上收到了该文件，但它没有数据。

下面是客户端的代码：

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(); 
    } 
} 

} 

服务器代码

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

你读循环是不正确的。他们应该是这样的形式：

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

否则您可能会丢失数据。

NB

• Java不 '已在使用IP' 抛出一个错误。准确。
• 你不需要睡觉。不要将睡眠添加到网络代码。它没有解决任何问题。

Answer 2

我的家人感谢您的回复，现在我知道我的错误是什么，我在我的客户端应用程序上输入了错误的IP地址。

然而EJP我会采取你的建议，以更好的字节检查时，写一个频道。