Java 实现nio文件复制（以图片复制为例）

public static void main(String[] args) throws IOException {

		RandomAccessFile file = new RandomAccessFile("1.png", "rw");
		FileChannel channel = file.getChannel();

		RandomAccessFile file1 = new RandomAccessFile("2.png", "rw");
		FileChannel channel1 = file1.getChannel();

		ByteBuffer buf = ByteBuffer.allocateDirect(32);
		for (; channel.read(buf) != -1;) {
			buf.flip();

			for (; buf.hasRemaining();) {
				channel1.write(buf);
			}

			buf.clear();
		}

		channel.close();
		channel1.close();

		file.close();
		file1.close();

	}

public static void main(String[] args) throws IOException {

//		RandomAccessFile file = new RandomAccessFile("1.png", "rw");
		FileChannel channel = FileChannel.open(Paths.get("1.png"), StandardOpenOption.READ,StandardOpenOption.WRITE);

//		RandomAccessFile file1 = new RandomAccessFile("2.png", "rw");
		FileChannel channel1 = FileChannel.open(Paths.get("5.png"), StandardOpenOption.READ,StandardOpenOption.WRITE,StandardOpenOption.CREATE);

		MappedByteBuffer buf = channel.map(MapMode.READ_WRITE, 0, channel.size());

		MappedByteBuffer buf1 = channel1.map(MapMode.READ_WRITE, 0, channel.size());

//		ByteBuffer buf = ByteBuffer.allocateDirect(32);
//		for (; channel.read(buf) != -1;) {
//			buf.flip();
//
//			for (; buf.hasRemaining();) {
//				channel1.write(buf);
//			}
//
//			buf.clear();
//		}

		byte[] dst = new byte[buf.limit()];

		buf.get(dst);

		buf1.put(dst);

		channel.close();
		channel1.close();

//		file.close();
//		file1.close();

	}