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NIO.MD

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建立非阻塞NIO流程

客户端：

  • 获取通道

    • TCP SocketChannel
    • UDP datagramChannel
    • 设置非阻塞configureBlocking(false)

  • 建立BufferByteBuffer.allocate(1024)

  • 将Buffer数据写入Channel

    • TCP
    buf.put(data);
buf.flip();
socketChannel.write(buf);
    • UPD
    byteBuffer.put(data);
byteBuffer.flip();
datagramChannel.send(byteBuffer, new InetSocketAddress("127.0.0.1", 9898));

    服务端：

  • 获取通道

    • TCP ServerSocketChannel
    • UDP datagramChannel
    • 设置非阻塞configureBlocking(false)
    • 绑定端口 bind(new InetSocketAddress(9898));

  • 获取选择器

    • 将通道注册到选择器上 channel.register(selector,SelectionKey.OP_ACCEPT) 此处可以监听通道的四种状态：
      • SelectionKey.OP_ACCEPT 准备就绪
      • SelectionKey.OP_WRITE 可读
      • SelectionKey.OP_ACCEPT 可写
      • SelectionKey.OP_CONNECT 连接上

  • 轮询选择器中的事件返回一个Set,对各种事件进行处理

//TCP
if(selectionKey.isAcceptable())
              {
                  //获取客户端的连接
                  SocketChannel socketChannel = serverSocketChannel.accept();
                  //切换成非阻塞模式
                  socketChannel.configureBlocking(false);
                  //注册到选择器上
                  socketChannel.register(selector,SelectionKey.OP_READ);
              }
              else if(selectionKey.isReadable())
              {
                  SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
                  //读取数据
                  ByteBuffer buf =ByteBuffer.allocate(1024);
                  int len = 0;
                  while((len = socketChannel.read(buf))!=-1)
                  {
                      buf.flip();
                      System.out.println(new String(buf.array(),0,len));
                      buf.clear();
                  }
              }

//UDP
   while (selector.select() > 0) {
                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                while (iterator.hasNext()) {
                    SelectionKey selectionKey = iterator.next();
                    if (selectionKey.isReadable()) {
                        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
                        datagramChannel.receive(byteBuffer);
                        System.out.println(new String(byteBuffer.array(), 0, byteBuffer.limit()));
                        byteBuffer.clear();
                    }
                    //使用完毕后取消Key
                    iterator.remove();
                }
            }