Java原生Nio服务端与客户端编写

Java原生Nio服务端与客户端的编写（待完善）

一、Nio服务端

public static void main(String[] args) throws IOException {
    // 创建服务器
    ServerSocketChannel server = ServerSocketChannel.open();
    // 绑定端口
    server.bind(new InetSocketAddress(6666));
    // 设置为非阻塞IO
    server.configureBlocking(false);
    // 创建一个IO多路复用选择器
    Selector selector = Selector.open();
    // selector注册到channel上
    server.register(selector, SelectionKey.OP_ACCEPT);
    while (true){
        /**
             * 阻塞方法。返回值代表发生事件的通道个数
             * 0 超时
             * 1 错误
             */
        int select = selector.select();
        // 代码运行到此处，说明有可读，可写，可连接的channel
        Set<SelectionKey> selectionKeys = selector.selectedKeys();
        Iterator<SelectionKey> iterator = selectionKeys.iterator();
        while (iterator.hasNext()) {
            SelectionKey selectionKey = iterator.next();
            iterator.remove();
            if (selectionKey.isAcceptable()) {
                System.out.println("有人连接了。。。");
                // 三次握手，进行连接
                SocketChannel accept = server.accept();
                accept.configureBlocking(false);
                accept.register(selector,SelectionKey.OP_READ, ByteBuffer.allocate(1024));
            }

            if (selectionKey.isReadable()) {
                System.out.println("读取到数据。。。");
                SocketChannel channel =(SocketChannel) selectionKey.channel();
                ByteBuffer buffer = (ByteBuffer) selectionKey.attachment();
                // 读取前清空buffer，清空上一个buffer
                buffer.clear();
                channel.read(buffer);
                System.out.println(new String(buffer.array(),0,buffer.position(), StandardCharsets.UTF_8));
            }

            if (selectionKey.isWritable()) {
                System.out.println("进入可写状态。。。");
                // TODO 待编写
            }
        }
    }
}

二、客户端的编写

public static void main(String[] args) throws IOException, InterruptedException {
    SocketChannel client = SocketChannel.open();
    client.connect(new InetSocketAddress(6666));
    client.configureBlocking(false);

    if (client.finishConnect()) {
        while (true) {
            Scanner sc = new Scanner(System.in);
            String next = sc.next();
            client.write(ByteBuffer.wrap(next.getBytes(StandardCharsets.UTF_8)));
        }
    }
}