java nio 使用Scanner无法正常使用

perry · 2020 年3 月 8 日 11:33

客户端
SocketChannel获取到管道然后转化成非阻塞式的创建指定缓冲区并写入数据，吧缓冲区的数据写入到管道中。
服务端
服务端利用ServerSocketChannel获取管道然后也是转换非阻塞绑定对应的socket的端口然后有对应的选择器以及监听事件的状态，正确的运行版本，代码如下：
客户端

    @Test
    public void client() throws IOException {
        //1.获取通道
        SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 9898));

        //2.切换成非阻塞模式
        socketChannel.configureBlocking(false);
        //3.创建指定缓冲区
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        Scanner scanner = new Scanner(System.in);
        int str = scanner.nextInt();
//        while(scanner.hasNext()){
//            String str = scanner.next();
        buffer.put((LocalDateTime.now().toString() + "\n").getBytes());
        buffer.flip();
        socketChannel.write(buffer);
        buffer.clear();
//        }

        //4.关闭通道
        socketChannel.close();
    }

服务端
//服务

    public static void main(String[] args) throws IOException {
        //1.获取通道
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        //2.切换成非阻塞模式
        serverSocketChannel.configureBlocking(false);
        //3.绑定连接
        serverSocketChannel.bind(new InetSocketAddress(9898));

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

        //5.将通道注册到选择器上,并且指定监听接受事件
        //读   SelectionKey.OP_READ          1
        //写   SelectionKey.OP_WRITE         4
        //连接 SelectionKey.OP_CONNECT       8
        //接收 SelectionKey.OP_ACCEPT        16
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

        //6.轮询式的获取选择器上已经“准备就绪”的事件
        while (selector.select() > 0) {
            //7.获取当前选择器中的所有注册的“选择键(已就绪的监听事件)”
            Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();

            while (iterator.hasNext()) {
                //8.获取准备“就绪”的事件
                SelectionKey selectionKey = iterator.next();

                //9.判断具体是什么事件准备就绪
                if (selectionKey.isAcceptable()) {
                    //10.若“接收就绪”，获取客户端的连接
                    SocketChannel socketChannel1 = serverSocketChannel.accept();
                    //11.切换非阻塞模式
                    socketChannel1.configureBlocking(false);
                    //12.将该通道注册到选择器上
                    socketChannel1.register(selector, SelectionKey.OP_READ);
                } else if (selectionKey.isReadable()) {
                    //13.获取当前选择器上的"读就绪"状态的通道
                    SocketChannel socketChannel = (SocketChannel) selectionKey.channel();

                    //14.读取数据
                    ByteBuffer buffer = ByteBuffer.allocate(1024);
                    int len = 0;
                    while ((len = socketChannel.read(buffer)) != -1) {
                        buffer.flip();
                        System.out.println(new String(buffer.array(),0,len));
                        buffer.clear();
                    }
                }
                //15.取消选择键 selectionKey
                iterator.remove();
            }
        }
    }

打印结果
服务端

客户端

错误的版本
客户端服务端不变

    public static void main(String[] args) throws IOException {
        //1.获取通道
        SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 9898));

        //2.切换成非阻塞模式
        socketChannel.configureBlocking(false);
        //3.创建指定缓冲区
        ByteBuffer buffer = ByteBuffer.allocate(1024);
        Scanner scanner = new Scanner(System.in);
        
        ==while (scanner.hasNext()) {==



            String str = scanner.next();
            buffer.put((LocalDateTime.now().toString() + "\n" + str).getBytes());
            buffer.flip();
            socketChannel.write(buffer);
            buffer.clear();
//
//            try {
//                TimeUnit.SECONDS.sleep(3);
//            } catch (InterruptedException e) {
//                e.printStackTrace();
//            }
        }
        //4.关闭通道
        socketChannel.close();
        }

然后
客户端

服务端