本文共 4262 字，大约阅读时间需要 14 分钟。

服务端

import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.*;import java.util.Iterator;public class MyServer {
       private int size = 1024;    private ServerSocketChannel serverSocketChannel;    private ByteBuffer  byteBuffer;    private Selector selector;    private int remoteClientNum = 0;    public MyServer(int port) throws IOException {
           initChannel(port);    }    public void initChannel(int port) throws IOException {
           serverSocketChannel = ServerSocketChannel.open();        serverSocketChannel.configureBlocking(false);        serverSocketChannel.bind(new InetSocketAddress(port));        selector =Selector.open();        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);        byteBuffer = ByteBuffer.allocate(size);    }    private void listener() throws IOException {
           while(true){
               int select = selector.select();            if(select==0){
                   continue;            }            Iterator
   
     iterator = selector.selectedKeys().iterator();            while(iterator.hasNext()){
                   SelectionKey key = iterator.next();                if(key.isAcceptable()){
                       ServerSocketChannel server = (ServerSocketChannel) key.channel();                    SocketChannel channel = server.accept();                    registerChannel(selector,channel,SelectionKey.OP_READ);                    remoteClientNum++;                    System.out.println("客户端连接数"+remoteClientNum);                    write(channel,"hello client".getBytes());                }                if(key.isReadable()){
                       read(key);                }                iterator.remove();            }        }    }    private void registerChannel(Selector selector,SocketChannel socketChannel,int opRead) throws IOException {
           if(socketChannel == null){
               return;        }        socketChannel.configureBlocking(false);        socketChannel.register(selector,opRead);    }    private void write(SocketChannel socketChannel,byte[] writeDate) throws IOException {
           byteBuffer.clear();        byteBuffer.put(writeDate);        byteBuffer.flip();        socketChannel.write(byteBuffer);    }    private void read(SelectionKey key) throws IOException {
           SocketChannel socketChannel = (SocketChannel)key.channel();        int count;        byteBuffer.clear();        while ((count=socketChannel.read(byteBuffer))>0){
               byteBuffer.flip();            while (byteBuffer.hasRemaining()){
                   System.out.print((char) byteBuffer.get());            }            byteBuffer.clear();        }       if(count < 0 ){
              socketChannel.close();       }    }    public static void main(String[] args) throws IOException {
           MyServer myServer = new MyServer(9999);        myServer.listener();    }}
   

客户端

import java.io.IOException;import java.net.InetSocketAddress;import java.nio.ByteBuffer;import java.nio.channels.SocketChannel;public class MyClient {
       private int  size = 1024;    private ByteBuffer  byteBuffer;    private SocketChannel socketChannel;    public void connectServer() throws IOException {
           socketChannel = SocketChannel.open();        socketChannel.connect(new InetSocketAddress("127.0.0.1",9999));        socketChannel.configureBlocking(false);        byteBuffer = ByteBuffer.allocate(size);        receive();    }    private void receive() throws IOException {
           while(true){
               byteBuffer.clear();            int count;            while ((count=socketChannel.read(byteBuffer))>0){
                   byteBuffer.flip();                while (byteBuffer.hasRemaining()){
                       System.out.print((char)byteBuffer.get());                }                send2Server("sayhi".getBytes());                byteBuffer.clear();            }        }    }    private void send2Server(byte[] bytes) throws IOException {
           byteBuffer.clear();        byteBuffer.put(bytes);        byteBuffer.flip();        socketChannel.write(byteBuffer);    }    public static void main(String[] args) throws IOException {
           new MyClient().connectServer();    }}