使用Channel、Buffer、Selector完成网络通信--非阻塞（一）

//客户端
	@Test
	public void client() throws IOException{
		
		//1. 获取通道
		SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1",8989));
		
		//2. 切换非阻塞模式
		socketChannel.configureBlocking(false);
		
		//3. 分配指定大小的缓冲区
		ByteBuffer buffer = ByteBuffer.allocate(1024);
		
		//4. 发送数据给服务端
		Scanner scanner = new Scanner(System.in);
		
		while(scanner.hasNext()){
			String data = scanner.next();
			buffer.put((LocalDateTime.now().toString()+"\n" + data).getBytes());
			buffer.flip();
			socketChannel.write(buffer);
			buffer.clear();
		}
		
		//5.关闭通道
		socketChannel.close();
	}
	
	//服务端
	@Test
	public void server() throws IOException{
		
		//1. 获取通道
		ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
	
		//2. 切换非阻塞模式
		serverSocketChannel.configureBlocking(false);
		
		//3. 绑定连接
		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上, 并且指定“监听接收事件”
		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. 获取当前选择器中所有注册的“选择键(已就绪的监听事件)”
			Set set = selector.selectedKeys();
			Iterator it = set.iterator();
			
			while(it.hasNext()){
				
				//8. 获取准备“就绪”的是事件
				SelectionKey selectionKey =	it.next();
				
				//9. 判断具体是什么事件准备就绪
				if(selectionKey.isAcceptable()){
						
					//10. 若“接收就绪”，获取客户端连接
					SocketChannel socketChannel = serverSocketChannel.accept();
					
					//11. 切换非阻塞模式
					socketChannel.configureBlocking(false);
					
					//12. 将该通道注册到选择器上
					socketChannel.register(selector,selectionKey.OP_READ);
					
				}else if(selectionKey.isReadable()){
					
					//13. 获取当前选择器上“读就绪”状态的通道
					SocketChannel socketChannel = (SocketChannel)selectionKey.channel();
					
					//14. 读取数据
					ByteBuffer buf = ByteBuffer.allocate(1024);
					int len = 0;
					while((len = socketChannel.read(buf)) > 0){
						buf.flip();
						System.out.println(new String(buf.array(),0,len));
						buf.clear();
					}
				}
			}
			//15. 取消选择键 SelectionKey
			it.remove();
		}
	}