AsynchronousFileChannel写数据

AsynchronousFileChannel写数据

public class TryNio implements CompletionHandler<Integer, AsynchronousFileChannel> { 
     int position = 0; 
     AsynchronousFileChannel channel = null; 
     ByteBuffer buffer = null; 

     public void completed(Integer result, AsynchronousFileChannel attachment) { 
      	System.out.println ("Bytes written: " + result); 
     } 
     
     public void failed(Throwable exc, AsynchronousFileChannel attachment) { 
       System.err.println ("Error!"); 
       exc.printStackTrace(); 
     } 

     public void doIt(String inFileName) { 
       Path file = Paths.get(inFileName); 
       try {
         channel = AsynchronousFileChannel.open(file, StandardOpenOption.WRITE); 
         buffer = ByteBuffer.allocate(1024); 
         Scanner in = new Scanner(System.in);
		 for(;;) {
			if(in.hasNextLine()) {
				buffer.put(in.nextLine().getBytes());
				buffer.flip();
       			channel.write(buffer, position, channel, this); 
       			buffer.clear();
			}
		 }			
       } catch (IOException e) { 
         System.err.println ("Could not open file: " + file+ e); 
         System.exit(1);
       } 
     } 

     public static void main (String [] args) { 
       TryNio tn = new TryNio(); 
       tn.doIt("/var/log/syslog"); 
     }
}