使用java NIO实现复制文件

前几天自己在做一个小实验来着，突然想到自己以前通过TCP(socket)的方式做过复制文件的事情，然后就想到貌似没试过UDP(DatagramSocket)的方式实现复制文件（其实这从头就是个错误的思路）。遂马上动手试验，理所当然的写到后面就发现这样的方式有缺陷（UDP本身特性决定了），但是在思索有不有其他的变通的方式实现的时候，无意中看到了NIO这个以前一直没注意的东西，当时还想通过NIO找一些变通方式，但是看着看着觉得NIO很有意思。例如，这个实现本地复制文件的方法

FileChannel src=new FileInputStream(new File(pathName_from)).getChannel();
FileChannel dst=new FileOutputStream(new File(pathName_to)).getChannel();
dst.transferFrom(src, 0, src.size());

可能很多人以前都知道和使用过NIO的很多特性，但是我以前真是没接触过所以受到触动，就学习了更多NIO的东西，然后就实现了下面的这个程序。
服务端：

package com.googlefans.NIO;

import java.io.FileOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;

public class NIOCopyServer implements Runnable{

	private FileChannel channel_to;
	private Selector selector;
	
	@SuppressWarnings("resource")
	public NIOCopyServer(int port) throws IOException{
		selector=Selector.open();
		ServerSocketChannel serverChannel=ServerSocketChannel.open();
		serverChannel.configureBlocking(false);
		serverChannel.socket().bind(new InetSocketAddress(InetAddress.getLocalHost(),port));
		serverChannel.register(selector, SelectionKey.OP_ACCEPT);
		channel_to=new FileOutputStream("E:\\testTo.txt").getChannel();
	}
	
	@Override
	public void run() {
		// TODO Auto-generated method stub
		while(true){
			try {
				selector.select();
				Iterator<SelectionKey> it=selector.selectedKeys().iterator();
				ByteBuffer inBuffer=ByteBuffer.allocate(1024);
				if(it.hasNext()){
					SelectionKey key=it.next();
					it.remove();
					if(key.isAcceptable()){
						ServerSocketChannel server=(ServerSocketChannel)key.channel();
						SocketChannel channel=server.accept();
						channel.configureBlocking(false);
						while(channel.read(inBuffer)!=-1){
							inBuffer.flip();
							channel_to.write(inBuffer);
							inBuffer.compact();
						}
						System.out.println("服务器端复制完毕！");
					}else if(key.isReadable()){
						read(key);
					}
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
		}
	}

	public void read(SelectionKey key) throws IOException{
		SocketChannel channel=(SocketChannel)key.channel();
		ByteBuffer byteBuf=ByteBuffer.allocateDirect(1024);
		channel.read(byteBuf);
		byte[] data=byteBuf.array();
		String msg=new String(data).trim();
		System.out.println("服务器端收到信息："+msg);
	}
	
}

客户端：

package com.googlefans.NIO;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;

public class NIOCopyClient implements Runnable{

	private Selector selector;
	private FileChannel channel_from;
	
	@SuppressWarnings("resource")
	public NIOCopyClient(InetAddress ip,int port) throws IOException{
		selector=Selector.open();
		SocketChannel channel=SocketChannel.open();
		channel.configureBlocking(false);
		channel.connect(new InetSocketAddress(ip,port));
		channel.register(selector, SelectionKey.OP_CONNECT);
		channel_from=new FileInputStream(new File("E:\\testFrom.txt")).getChannel();
	}
	
	@Override
	public void run() {
		// TODO Auto-generated method stub
		while(true){
			try {
				selector.select();
				Iterator<SelectionKey> it=selector.selectedKeys().iterator();
				ByteBuffer outBuffer=ByteBuffer.allocate(1024);
				if(it.hasNext()){
					SelectionKey key=it.next();
					it.remove();
					if(key.isConnectable()){
						SocketChannel channel=(SocketChannel)key.channel();
						if(channel.isConnectionPending()){
							channel.finishConnect();
						}
						channel.configureBlocking(false);
						while(channel_from.read(outBuffer)!=-1){
							outBuffer.flip();
							channel.write(outBuffer);
							outBuffer.compact();
						}
						System.out.println("客户端上传完毕！");
					}else if(key.isReadable()){
						read(key);
					}
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
	}

	public void read(SelectionKey key) throws IOException{
		SocketChannel channel=(SocketChannel)key.channel();
		ByteBuffer bb=ByteBuffer.allocate(1024);
		channel.read(bb);
		byte[] bytes=bb.array();
		String msg=new String(bytes).trim();
		System.out.println("客户端收到信息："+msg);
	}
}

实现类：

package com.googlefans.NIO;

import java.io.IOException;
import java.net.InetAddress;

public class NIOCopy {

	private final static int PORT=5111;
	public static void main(String[] args){
		try {
			Thread server=new Thread(new NIOCopyServer(PORT));
			Thread client=new Thread(new NIOCopyClient(InetAddress.getLocalHost(), PORT));
			server.start();
			client.start();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

当然我这段程序还是有很多不令人满意的地方，比如read（）方法。还是希望各位ITeye的大牛们多多指导。