Java nio Server实现

Java NIO 提供了反应堆模式非阻塞的Socket通信，代码很简单

public class TcpServer implements Runnable {private ServerSocketChannel socketChannel;private Selector selector;private int activeSockets;private int port;public TcpServer(){activeSockets = 0;port = 9999;try {socketChannel = ServerSocketChannel.open();selector = Selector.open();ServerSocket socket = socketChannel.socket();socket.bind(new InetSocketAddress(port));socketChannel.configureBlocking(false);socketChannel.register(selector, SelectionKey.OP_ACCEPT);} catch (IOException e) {e.printStackTrace();}}@Overridepublic void run() {while(true){try {selector.select();} catch (IOException e) {continue;}Set<SelectionKey> keys = selector.selectedKeys();activeSockets = keys.size();if(activeSockets==0){continue;}for(SelectionKey key:keys){if(key.isAcceptable()){doServerSocketEvent(key);continue;}if(key.isReadable()){doClientReadEvent(key);continue;}if(key.isWritable()){doClientWriteEvent(key);continue;}}}}private void doServerSocketEvent(SelectionKey key) {SocketChannel client = null;ServerSocketChannel server = (ServerSocketChannel)key.channel();try {client = server.accept();if(client == null){return;}client.configureBlocking(false);client.register(selector, SelectionKey.OP_READ|SelectionKey.OP_WRITE);} catch (IOException e) {try {client.close();} catch (IOException e1) {e1.printStackTrace();}}}private void doClientWriteEvent(SelectionKey key) {SocketChannel socketChannel = (SocketChannel)key.channel();ByteBuffer buffer = ByteBuffer.allocate(10);byte[] data = "0000000000".getBytes();buffer.put(data);buffer.flip();try {socketChannel.write(buffer);} catch (IOException e) {e.printStackTrace();}}private void doClientReadEvent(SelectionKey key) {ByteBuffer receiveBuffer;ByteBuffer buffer = ByteBuffer.allocate(1024);SocketChannel socketChannel = (SocketChannel)key.channel();if(socketChannel.isOpen()){int nBytes = 0;buffer.clear();try {nBytes = socketChannel.read(buffer);} catch (IOException e) {e.printStackTrace();}buffer.flip();if (nBytes > 0) {receiveBuffer = ByteBuffer.allocate(nBytes);receiveBuffer.clear();buffer.get(receiveBuffer.array());receiveBuffer.flip();}}}public static void main(String[] args) {TcpServer server = new TcpServer();new Thread(server).start();}}