非阻塞的示例

这篇博客讲的很细

https://www.jianshu.com/p/191041073919

public class client2 {

public static void main(String[] args)throws Exception {
  client();
}

public static void client()throws Exception{

    //1建立网络套接字
    SocketChannel socketChannel = SocketChannel.open
            (new InetSocketAddress("127.0.0.1",8989));

    //2切换为非阻塞模式
    socketChannel.configureBlocking(false);

    //3创建缓冲区
    ByteBuffer buffer=ByteBuffer.allocate(1024);

    //4发送数据给服务器
	
    Scanner scanner =new Scanner(System.in);
    while (scanner.hasNext()) {
        String str = scanner.next();
        buffer.put((new Date().toString()+"\n"+str).getBytes());
        buffer.flip();
        socketChannel.write(buffer);
        buffer.clear();
    }


    //5关闭通道
    socketChannel.close();
}

}

public class Server2 {

public static void main(String[] args)throws Exception {
 server();
}

public static void server()throws Exception{

//1 打开服务器端套接字通讯
   ServerSocketChannel serverSocketChannel=ServerSocketChannel.open();

   //2切换为非阻塞模式
   serverSocketChannel.configureBlocking(false);

   //3绑定端口
   serverSocketChannel.bind(new InetSocketAddress(8989));

   //4获取选择器
   Selector selector =Selector.open();

   //5将通道注册到选择器中,并选择进行哪一种操做,监听接收事件
   serverSocketChannel.register(selector,SelectionKey.OP_ACCEPT);

   //6 轮询选择器上已经准备的事件
   while (selector.select()>0){
       //获取当前选择中全部注册的选择键
       Iterator<SelectionKey> iterator=selector.selectedKeys().iterator();

       //迭代器
       while (iterator.hasNext()){
           //获取准备就绪的事件
           SelectionKey selectionKey=iterator.next();
           //判断是哪一种事件的就绪
           if(selectionKey.isAcceptable()){
               //获取客户端的套接字通道
               SocketChannel socketChannel=serverSocketChannel.accept();
               //切换为非阻塞模式
               socketChannel.configureBlocking(false);
               //注入到选择器中，操做为读
               socketChannel.register(selector,SelectionKey.OP_READ);
       }else if(selectionKey.isReadable()){
               SocketChannel socketChannel=(SocketChannel) selectionKey.channel();
               //获得一个缓冲区
               int len=0;
               ByteBuffer buffer=ByteBuffer.allocate(1024);
               while ((len=socketChannel.read(buffer))>0){
                   buffer.flip();
                   System.out.println(new String(buffer.array(),0,len));
                   buffer.clear();
               }
           }

           //取消选择键
           iterator.remove();

       }
   }
}

}