Java tutorial
//package com.java2s; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.channels.ReadableByteChannel; import java.nio.channels.WritableByteChannel; public class Main { public static void fastChannelCopy(final ReadableByteChannel src, final WritableByteChannel dest) throws IOException { final ByteBuffer buffer = ByteBuffer.allocateDirect(16 * 1024); while (src.read(buffer) != -1) { // prepare the buffer to be drained buffer.flip(); // write to the channel, may block dest.write(buffer); // If partial transfer, shift remainder down // If buffer is empty, same as doing recycle() buffer.compact(); } // EOF will leave buffer in fill state buffer.flip(); // make sure the buffer is fully drained. while (buffer.hasRemaining()) { dest.write(buffer); } } }