Java NIO Channel to Channel Transfers

transferFrom（）
transferTo（）

　　如果两个channel中有一个是filechannel，那么两个channel就可以互相传输数据。

　TransferFrom()

　　FileChannel.transferFrom()将一个channel中的数据传输到FileChannel中去。上例子

 1 RandomAccessFile fromFile = new RandomAccessFile("fromFile.txt", "rw");
 2 FileChannel      fromChannel = fromFile.getChannel();
 3 
 4 RandomAccessFile toFile = new RandomAccessFile("toFile.txt", "rw");
 5 FileChannel      toChannel = toFile.getChannel();
 6 
 7 long position = 0;
 8 long count    = fromChannel.size();
 9 
10 toChannel.transferFrom(fromChannel, position, count);

　　一些SocketChannel实现可能只会传输已经准备好的数据，即使还有正在准备的很多可用数据。因此SocketChannel可能不会传输全部的数据到FileChannel中。

　TransferTo()

　　FileChannel.transferTo()是FileChannel向其他的channel传输数据。

 1 RandomAccessFile fromFile = new RandomAccessFile("fromFile.txt", "rw");
 2 FileChannel      fromChannel = fromFile.getChannel();
 3 
 4 RandomAccessFile toFile = new RandomAccessFile("toFile.txt", "rw");
 5 FileChannel      toChannel = toFile.getChannel();
 6 
 7 long position = 0;
 8 long count    = fromChannel.size();
 9 
10 fromChannel.transferTo(position, count, toChannel);

　　这里SocketChannel，还是老毛病。