NIO示例

NIO服务端代码：

public class NIOServer {
	
	private Selector selector;

	
	public void startServer(int port) throws IOException {

		ServerSocketChannel serverChannel = ServerSocketChannel.open();
		// 设置通道为非阻塞
		serverChannel.configureBlocking(false);

		serverChannel.socket().bind(new InetSocketAddress(port));

		this.selector = Selector.open();
		
		serverChannel.register(selector, SelectionKey.OP_ACCEPT);
	}

	
	public void listen() throws IOException {
		while (true) {
			//当注册的事件到达时，方法返回；否则,该方法会一直阻塞
			selector.select();
			Iterator<SelectionKey> it = this.selector.selectedKeys().iterator();
			while (it.hasNext()) {
				SelectionKey key = (SelectionKey) it.next();
				// 此处一定要删除
				it.remove();

				if (key.isAcceptable()) {
				    
					ServerSocketChannel server = (ServerSocketChannel) key
							.channel();
					
					SocketChannel channel = server.accept();
					System.out.println("remote socket is:"+channel.socket().getInetAddress());
					channel.configureBlocking(false);

					channel.write(ByteBuffer.wrap(new String("send one msg to client").getBytes()));
	
					channel.register(this.selector, SelectionKey.OP_READ);
					
				} else if (key.isReadable()) {
						read(key);
				}

			}

		}
	}
	
	public void read(SelectionKey key) throws IOException{
	
		SocketChannel channel = (SocketChannel) key.channel();
		
		ByteBuffer buffer = ByteBuffer.allocate(1024);
		int len = channel.read(buffer);
		byte[] data = new byte[len];
		System.arraycopy(buffer.array(), 0, data, 0, len);
		String msg = new String(data).trim();
		System.out.println("server receive one msg:"+msg);
		ByteBuffer outBuffer = ByteBuffer.wrap(msg.getBytes());
		channel.write(outBuffer);
	}
	
	public static void main(String[] args) throws IOException {
		NIOServer server = new NIOServer();
		server.startServer(8080);
		server.listen();
	}

}

NIO客户端代码：

public class NIOClient {
    
	private Selector selector;

	
	public void initClient(String ip,int port) throws IOException {
	
		SocketChannel channel = SocketChannel.open();
		
		channel.configureBlocking(false);
		
		this.selector = Selector.open();
		
		channel.connect(new InetSocketAddress(ip,port));
		channel.register(selector, SelectionKey.OP_CONNECT);
	}

	public void listen() throws IOException {
		while (true) {
			selector.select();
			Iterator<SelectionKey> it = this.selector.selectedKeys().iterator();
			while (it.hasNext()) {
				SelectionKey key = (SelectionKey) it.next();

				it.remove();

				if (key.isConnectable()) {
					SocketChannel channel = (SocketChannel) key.channel();
					if(channel.isConnectionPending()){
						channel.finishConnect();
						
					}

					channel.configureBlocking(false);

					channel.write(ByteBuffer.wrap(new String("你在他乡还好吗").getBytes()));

					channel.register(this.selector, SelectionKey.OP_READ);
					
				} else if (key.isReadable()) {
						read(key);
				}

			}

		}
	}

	public void read(SelectionKey key) throws IOException{
	    SocketChannel channel = (SocketChannel) key.channel();
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        int len = channel.read(buffer);
        byte[] data = new byte[len];
        System.arraycopy(buffer.array(), 0, data, 0, len);
        String msg = new String(data).trim();
        System.out.println("client receive one msg:"+msg);
        ByteBuffer outBuffer = ByteBuffer.wrap(msg.getBytes());
	}
	
	
	public static void main(String[] args) throws IOException {
		NIOClient client = new NIOClient();
		client.initClient("localhost",8080);
		client.listen();
	}

}