NIO 服务器和客户端 demo 如下：
public class TestNonBlockingNIO { //客户端 @Test public void client() throws IOException{ // 1. 获取通道 SocketChannel sChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 9898)); // 2. 切换非阻塞模式 sChannel.configureBlocking(false); // 3. 分配指定大小的缓冲区 ByteBuffer buf = ByteBuffer.allocate(1024); // 4. 发送数据给服务端 String str = "hello"; buf.put((new Date().toString() + " " + str).getBytes()); buf.flip(); sChannel.write(buf); sChannel.shutdownOutput(); // 5. 关闭通道 sChannel.close(); } //服务端 @Test public void server() throws IOException{ //1. 获取通道 ServerSocketChannel ssChannel = ServerSocketChannel.open(); //2. 切换非阻塞模式 ssChannel.configureBlocking(false); //3. 绑定连接 ssChannel.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“监听接收事件” ssChannel.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)” Iterator<SelectionKey> it = selector.selectedKeys().iterator(); while(it.hasNext()){ //8. 获取准备“就绪”的是事件 SelectionKey sk = it.next(); //9. 判断具体是什么事件准备就绪 if(sk.isAcceptable()){ ServerSocketChannel ss = (ServerSocketChannel) sk.channel(); //10. 若“接收就绪”，获取客户端连接 SocketChannel sChannel = ss.accept(); //11. 切换非阻塞模式 sChannel.configureBlocking(false); //12. 将该通道注册到选择器上 sChannel.register(selector, SelectionKey.OP_READ); }else if(sk.isReadable()){ //13. 获取当前选择器上“读就绪”状态的通道 SocketChannel sChannel = (SocketChannel) sk.channel(); //14. 读取数据 ByteBuffer buf = ByteBuffer.allocate(1024); int len = 0; while((len = sChannel.read(buf)) > 0 ){ buf.flip(); System.out.println(new String(buf.array(), 0, len)); buf.clear(); } if(len == -1){ System.out.println("断开"); sChannel.close(); } } //15. 取消选择键 SelectionKey it.remove(); } } } }