NIO利用文件流复制文件

public static void nioCopyFile(String resource, String destination)
            throws IOException {
        FileInputStream fis = new FileInputStream(resource);
        FileOutputStream fos = new FileOutputStream(destination);
        FileChannel readChannel = fis.getChannel(); //读文件通道
        FileChannel writeChannel = fos.getChannel(); //写文件通道
        ByteBuffer buffer = ByteBuffer.allocate(1024); //读入数据缓存
        while (true) {
            buffer.clear();
            int len = readChannel.read(buffer); //读入数据
            if (len == -1) {
                break;
//读取完毕
            }
            buffer.flip();
            writeChannel.write(buffer);
//写入文件
        }
        readChannel.close();
        writeChannel.close();
    }