服务端代码:
import java.io.IOException; import java.net.InetSocketAddress; import java.net.ServerSocket; import java.net.Socket; import java.nio.ByteBuffer; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel; import java.nio.charset.Charset; import java.util.HashMap; import java.util.Map; import java.util.Set; public class NIOSServer { private int port = 8888; //解码buffer private Charset cs = Charset.forName("utf-8"); /*接受数据缓冲区*/ private static ByteBuffer sBuffer = ByteBuffer.allocate(1024); /*发送数据缓冲区*/ private static ByteBuffer rBuffer = ByteBuffer.allocate(1024); /*映射客户端channel */ private Map<String, SocketChannel> clientsMap = new HashMap<String, SocketChannel>(); private static Selector selector; public NIOSServer(int port) { this.port = port; try { init(); } catch (Exception e) { e.printStackTrace(); } } private void init() throws IOException { /* *启动服务器端,配置为非阻塞,绑定端口,注册accept事件 *ACCEPT事件:当服务端收到客户端连接请求时,触发该事件 */ ServerSocketChannel serverSocketChannel = ServerSocketChannel.open(); serverSocketChannel.configureBlocking(false); ServerSocket serverSocket = serverSocketChannel.socket(); serverSocket.bind(new InetSocketAddress(port)); selector = Selector.open(); serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT); System.out.println("server start on port:" + port); } /** * 服务器端轮询监听,select方法会一直阻塞直到有相关事件发生或超时 */ private void listen() { while (true) { try { selector.select();//返回值为本次触发的事件数 Set<SelectionKey> selectionKeys = selector.selectedKeys(); for (SelectionKey key : selectionKeys) { handle(key); } selectionKeys.clear();//清除处理过的事件 } catch (Exception e) { e.printStackTrace(); break; } } } /** * 处理不同的事件 */ private void handle(SelectionKey selectionKey) throws IOException { ServerSocketChannel server = null; SocketChannel client = null; String receiveText = null; int count = 0; if (selectionKey.isAcceptable()) { /* * 客户端请求连接事件 * serversocket为该客户端建立socket连接,将此socket注册READ事件,监听客户端输入 * READ事件:当客户端发来数据,并已被服务器控制线程正确读取时,触发该事件 */ server = (ServerSocketChannel)selectionKey.channel(); client = server.accept(); client.configureBlocking(false); client.register(selector, SelectionKey.OP_READ); } else if (selectionKey.isReadable()) { /* * READ事件,收到客户端发送数据,读取数据后继续注册监听客户端 */ client = (SocketChannel)selectionKey.channel(); rBuffer.clear(); count = client.read(rBuffer); if (count > 0) { rBuffer.flip(); receiveText = String.valueOf(cs.decode(rBuffer).array()); System.out.println(client.toString() + ":" + receiveText); dispatch(client, receiveText); client = (SocketChannel)selectionKey.channel(); //client.register(selector, SelectionKey.OP_READ); } } } /** * 把当前客户端信息 推送到其他客户端 */ private void dispatch(SocketChannel client, String info) throws IOException { Socket s = client.socket(); String name = "[" + s.getInetAddress().toString().substring(1) + ":" + Integer.toHexString(client.hashCode()) + "]"; if (!clientsMap.isEmpty()) { for (Map.Entry<String, SocketChannel> entry : clientsMap.entrySet()) { SocketChannel temp = entry.getValue(); if (!client.equals(temp)) { sBuffer.clear(); sBuffer.put((name + ":" + info).getBytes()); sBuffer.flip(); //输出到通道 temp.write(sBuffer); } } } clientsMap.put(name, client); } public static void main(String[] args) throws IOException { NIOSServer server = new NIOSServer(7777); server.listen(); } }
客户端,可运行多个
import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.SocketChannel; import java.util.Date; import java.util.Scanner; import java.util.Set; public class NIOSClient { /*发送数据缓冲区*/ private static ByteBuffer sBuffer = ByteBuffer.allocate(1024); /*接受数据缓冲区*/ private static ByteBuffer rBuffer = ByteBuffer.allocate(1024); /*服务器端地址*/ private InetSocketAddress SERVER; private static Selector selector; private static SocketChannel client; private static String receiveText; private static String sendText; private static int count = 0; public NIOSClient(int port) { SERVER = new InetSocketAddress("localhost", port); init(); } public void init() { try { /* * 客户端向服务器端发起建立连接请求 */ SocketChannel socketChannel = SocketChannel.open(); socketChannel.configureBlocking(false); selector = Selector.open(); socketChannel.register(selector, SelectionKey.OP_CONNECT); socketChannel.connect(SERVER); /* * 轮询监听客户端上注册事件的发生 */ while (true) { selector.select(); Set<SelectionKey> keySet = selector.selectedKeys(); for (final SelectionKey key : keySet) { handle(key); } ; keySet.clear(); } } catch (Exception e) { e.printStackTrace(); } } public static void main(String[] args) throws IOException { new NIOSClient(7777); } private void handle(SelectionKey selectionKey) throws IOException { if (selectionKey.isConnectable()) { /* * 连接建立事件,已成功连接至服务器 */ client = (SocketChannel)selectionKey.channel(); if (client.isConnectionPending()) { client.finishConnect(); System.out.println("connect success !"); sBuffer.clear(); sBuffer.put((new Date() + " connected!").getBytes()); sBuffer.flip(); client.write(sBuffer);//发送信息至服务器 /* 原文来自站长网 * 启动线程一直监听客户端输入,有信息输入则发往服务器端 * 因为输入流是阻塞的,所以单独线程监听 */ new Thread() { @Override public void run() { while (true) { try { sBuffer.clear(); Scanner cin = new Scanner(System.in); sendText = cin.nextLine(); System.out.println(sendText); /* * 未注册WRITE事件,因为大部分时间channel都是可以写的 */ sBuffer.put(sendText.getBytes("utf-8")); sBuffer.flip(); client.write(sBuffer); } catch (IOException e) { e.printStackTrace(); break; } } }; }.start(); } //注册读事件 client.register(selector, SelectionKey.OP_READ); } else if (selectionKey.isReadable()) { /* * 读事件触发 * 有从服务器端发送过来的信息,读取输出到屏幕上后,继续注册读事件 * 监听服务器端发送信息 */ client = (SocketChannel)selectionKey.channel(); rBuffer.clear(); count = client.read(rBuffer); if (count > 0) { receiveText = new String(rBuffer.array(), 0, count); System.out.println(receiveText); client = (SocketChannel)selectionKey.channel(); client.register(selector, SelectionKey.OP_READ); } } } }