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服务端

github源码：https://github.com/JolyouLu/JAVAIO.git

public class GroupChatServer {       //定义属性    private Selector selector;    private ServerSocketChannel listenChannel;    private static final int PORT = 6666;    //构造器 完成初始化工作    public GroupChatServer() {           try {               //得到选择器            selector = Selector.open();            //初始化ServerSocketChannel            listenChannel = ServerSocketChannel.open();            //绑定端口            listenChannel.socket().bind(new InetSocketAddress(PORT));            //设置非阻塞模式            listenChannel.configureBlocking(false);            //将来listenChannel注册到Selector            listenChannel.register(selector, SelectionKey.OP_ACCEPT);        }catch (IOException e){               e.printStackTrace();        }    }    //监听    public void listen(){           try {               //循环监听            while (true){                   int count = selector.select(2000); //阻塞2秒监听，通道有没有事件发生                if (count > 0){    //返回>0 有事件要处理                    //遍历selectedKeys集合                    Iterator
   
     iterator = selector.selectedKeys().iterator();                    while (iterator.hasNext()){                           //获取SelectionKey                        SelectionKey key = iterator.next();                        if (key.isAcceptable()){    //如果通道发生，客户端连接事件                            //为连接的客户端，生成socketChannel                            SocketChannel socketChannel = listenChannel.accept();                            //切换非阻塞模式                            socketChannel.configureBlocking(false);                            //把socketChannel注册到selector中，并监听读事件                            socketChannel.register(selector,SelectionKey.OP_READ);                            //提示客户端连接上了                            System.out.println(socketChannel.getRemoteAddress() + " 客户端 上线");                        }                        if (key.isReadable()){   //如果通道发生，可读事件                            //处理读                            readData(key);                        }                        //清理读取的selectedKeys容器 防止重复处理                        iterator.remove();                    }                }            }        }catch (Exception e){               e.printStackTrace();        }finally {           }    }    //读取客户端消息    private void readData(SelectionKey key){           //定义一个SocketChannel        SocketChannel channel = null;        try {               //取到关联的channel            channel = (SocketChannel) key.channel();            //创建buffer            ByteBuffer buffer = ByteBuffer.allocate(1024);            int count = channel.read(buffer);            //根据count的值做处理            if (count > 0){    //读取到数据                //把缓冲区的数据转字符串                String msg = new String(buffer.array(), "GBK");                //输出消息                System.out.println("from 客户端："+ msg);                //向其它客户端转发消息                sendInfoToOtherClients(msg,channel);            }        }catch (IOException e){               try {                   System.out.println(channel.getRemoteAddress() + " 离线了..");                //取消注册                key.cancel();                //关闭通道                channel.close();            } catch (IOException ioException) {                   ioException.printStackTrace();            }        }    }    //转发消息给其它客户端(channel)    private void sendInfoToOtherClients(String msg,SocketChannel self) throws IOException {           System.out.println("服务器转发消息中...");        //遍历 所有的注册到Selector的SocketChannel排查self        for (SelectionKey key : selector.keys()) {               //取出通道            Channel targetChannel = key.channel();            //targetChanneld的类型是SocketChannel，并且targetChannel不是自己            if (targetChannel instanceof SocketChannel && targetChannel != self){                   //转型                SocketChannel dest = (SocketChannel)targetChannel;                //将来msg 存到buffer                ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes("GBK"));                //将来buffer的数据写入通道                dest.write(buffer);            }        }    }    public static void main(String[] args) {           //初始化服务器对象        GroupChatServer chatServer = new GroupChatServer();        chatServer.listen();    }}
   

客户端

public class GroupChatClient {       //定义相关属性    private final String HOST = "127.0.0.1"; //服务器IP    private final int PORT = 6666; //服务器端口    private Selector selector;    private SocketChannel socketChannel;    private String username;    //构造器,初始化    public GroupChatClient() {           try {               //得到选择器            selector = Selector.open();            //连接服务            socketChannel = SocketChannel.open(new InetSocketAddress(HOST,PORT));            //设置非阻塞            socketChannel.configureBlocking(false);            //将来socketChannel注册到Selector，关注读事件            socketChannel.register(selector, SelectionKey.OP_READ);            //得到username            username = socketChannel.getLocalAddress().toString().substring(1);            System.out.println(username + " is ok ...");        }catch (Exception e){               e.printStackTrace();        }    }    //向服务器发送消息    public void sendInfo(String info){           info = username + " 说：" + info;        try {               socketChannel.write(ByteBuffer.wrap(info.getBytes("GBK")));        }catch (IOException e){               e.printStackTrace();        }    }    //读取从服务器端回复的消息    public void readInfo(){           try {               int readChannels = selector.select(2000);            if (readChannels > 0){   //有可用的通道                Iterator
   
     iterator = selector.selectedKeys().iterator();                while (iterator.hasNext()){                       SelectionKey key = iterator.next();                    if (key.isReadable()){                           //得到相关的通道                        SocketChannel socketChannel = (SocketChannel) key.channel();                        //得到一个Buffer                        ByteBuffer buffer = ByteBuffer.allocate(1024);                        //buffer 读取通道数据                        socketChannel.read(buffer);                        //把读到缓冲区的数据转成字符串                        String msg = new String(buffer.array());                        System.out.println(msg.trim());                    }                    iterator.remove();                }            }        }catch (IOException e){               e.printStackTrace();        }    }    public static void main(String[] args) {           //启动客户端        GroupChatClient chatClient = new GroupChatClient();        //启动一个线程,每隔开3秒读取服务器发送的数据        new Thread(new Runnable() {               @Override            public void run() {                   while (true){                       chatClient.readInfo();                    try {                           Thread.currentThread().sleep(3000);                    } catch (InterruptedException e) {                           e.printStackTrace();                    }                }            }        }).start();        //发送数据        Scanner scanner = new Scanner(System.in);        while (scanner.hasNextLine()){               String s = scanner.nextLine();            chatClient.sendInfo(s);        }    }}
   

测试

设置启动参数，当前类可以同时运行多个

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