Java Nio Socket通讯

Server端：

#############服务器端连接请求处理###############
public class MultiplexerServer implements Runnable {

	/**多路复用器,SocketChannel注册到Selector.Selector轮询监听Channel网络事件*/
	private Selector selector;

	private ServerSocketChannel serverSocketChannel;

	private boolean stop;

	public MultiplexerServer(int port) {
		try {
			selector = Selector.open();
			serverSocketChannel = ServerSocketChannel.open();
			serverSocketChannel.configureBlocking(false);
			serverSocketChannel.socket().bind(new InetSocketAddress(port), 1024);
			serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
			System.out.println("[" + getClass().getSimpleName() + "] start in port [" + port + "]");
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

	@Override
	public void run() {
		while (!stop) {
			try {
				selector.select(1000);
				Set<SelectionKey> selectionKeys = selector.selectedKeys();
				Iterator<SelectionKey> iterator = selectionKeys.iterator();
				while (iterator.hasNext()) {
					SelectionKey selectionKey = iterator.next();
					iterator.remove();
					try {
						/**处理请求连接*/
						handle(selectionKey);
					} catch (Exception e) {
						if (selectionKey != null) {
							selectionKey.cancel();
							if (selectionKey.channel() != null) {
								selectionKey.channel().close();
							}
						}
					}
				}
			} catch (IOException e) {
				e.printStackTrace();
			}

		}
		try {
			/**Selector关闭后,注册的Channel及Pipe等资源都会自动关闭(不需要重复关闭资源)*/
			if (selector != null) {
				selector.close();
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	public void stop(boolean stop) {
		this.stop = stop;
	}

	private void handle(SelectionKey key) throws IOException {
		if (key.isValid()) {
			if (key.isAcceptable()) {				// 新连接
				ServerSocketChannel ssc = (ServerSocketChannel) key.channel();
				SocketChannel sc = ssc.accept();
				sc.configureBlocking(false);
				sc.register(selector, SelectionKey.OP_READ);
			}
			if (key.isReadable()) {
				SocketChannel sc = (SocketChannel) key.channel();
				ByteBuffer buffer = ByteBuffer.allocate(1024);
				int readBytes = sc.read(buffer);
				if (readBytes > 0) {
					buffer.flip();
					byte[] bytes = new byte[buffer.remaining()];
					buffer.get(bytes);
					System.out.println(new String(bytes, "UTF-8"));
					/**响应客户端请求*/
					response(sc, new Respone("server received", 0));
				} else if (readBytes == 0) {
					;
				} else {							// 客户端关闭连接
					key.cancel();
					sc.close();
				}
			}
		}
	}

	private void response(SocketChannel sc, Respone respone) throws IOException{
		if (respone != null && sc != null && sc.isConnected()) {
			String json = respone.toString();
			byte[] bytes = json.getBytes();
			ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
			buffer.put(bytes);
			buffer.flip();
			sc.write(buffer);
		}
	}
}

###############服务器端响应################
public class Respone {

	private String data;

	private int status;

	public Respone() {

	}

	public Respone(String data, int status) {
		this.data = data;
		this.status = status;
	}

	public String getData() {
		return data;
	}

	public void setData(String data) {
		this.data = data;
	}

	public int getStatus() {
		return status;
	}

	public void setStatus(int status) {
		this.status = status;
	}

	@Override
	public String toString() {
		return "{\"data\":" + data + ",\"status\":" + status +  "}";
	}
}

#############服务端入口##############
public class NioServer {

	public static void start(int port) {
		Executors.newSingleThreadExecutor().submit(new MultiplexerServer(port));
	}

	public static void main(String []args) {
		int port = 8181;
		if (args != null &&  args.length == 1) {
			port = Integer.parseInt(args[0]);
		}
		NioServer.start(port);
	}
}

　　Client段：

public class NioClientConnection implements Runnable {

	private String host;

	private int port;

	private Selector selector;

	private SocketChannel socketChannel;

	private boolean stop;

	public NioClientConnection(String host, int port) {
		this.host = host;
		this.port = port;
		try {
			selector = Selector.open();
			socketChannel = SocketChannel.open();
			socketChannel.configureBlocking(false);
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

	@Override
	public void run() {
		try {
			connect();
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
		while (!stop) {
			try {
				selector.select(1000);
				Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
				while (iterator.hasNext()) {
					SelectionKey selectionKey = iterator.next();
					try {
						// 响应服务
						doResponse(selectionKey);
					} catch (Exception e) {
						e.printStackTrace();
						if (selectionKey != null) {
							selectionKey.cancel();
							if (selectionKey.channel() != null) {
								selectionKey.channel().close();
							}
						}
					}
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		try {
			if (selector != null) {
				selector.close();
			}
		} catch (Exception e) {
			e.printStackTrace();
			System.exit(1);
		}
	}

	private void connect() throws IOException {
		if (socketChannel.connect(new InetSocketAddress(host, port))) {
			socketChannel.register(selector, SelectionKey.OP_READ);
			send(socketChannel);
		} else {
			socketChannel.register(selector, SelectionKey.OP_CONNECT);
		}
	}

	private void send(SocketChannel sc) throws IOException {
		byte[] bytes = "Hello, Server".getBytes();
		ByteBuffer buffer = ByteBuffer.allocate(bytes.length);
		buffer.put(bytes);
		buffer.flip();
		sc.write(buffer);
		if (!buffer.hasRemaining()) {
			System.out.println("send msg sucess");
		}
	}

	private void doResponse(SelectionKey key) throws IOException{
		if (key.isValid()) {
			SocketChannel sc = (SocketChannel) key.channel();
			if (key.isConnectable()) {
				if (sc.finishConnect()) {
					sc.register(selector, SelectionKey.OP_READ);
					send(socketChannel);
				}
			}
			if (key.isReadable()) {
				ByteBuffer buffer = ByteBuffer.allocate(1024);
				int readBytes = sc.read(buffer);
				if (readBytes > 0) {
					buffer.flip();
					byte[] bytes = new byte[buffer.remaining()];
					buffer.get(bytes);
					System.out.println(new String(bytes, "UTF-8"));
					/**关闭连接*/
					stop = true;
				} else if (readBytes == 0) {
					;
				} else {							// 客户端关闭连接
					key.cancel();
					sc.close();
				}
			}
		}
	}

}

public class NioClient {

	public static void start(String host, int port) {
		Executors.newSingleThreadExecutor().execute(new NioClientConnection(host, port));
	}

	public static void main(String []args) {
		String host = "127.0.0.1";
		int port = 8181;
		if (args != null && args.length == 2) {
			host = args[0];
			port = Integer.valueOf(args[1]);
		}
		NioClient.start(host, port);
	}

}