NIO教程（2）https://developer.aliyun.com/article/1530796
服务端流程
- 1、当客户端连接服务端时，服务端会通过 ServerSocketChannel 得到 SocketChannel：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(9999));
- 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);
- 轮询式的获取选择器上已经“准备就绪”的事件
//轮询式的获取选择器上已经“准备就绪”的事件 while (selector.select() > 0) { System.out.println("轮一轮"); //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()) { //10. 若“接收就绪”，获取客户端连接 SocketChannel sChannel = ssChannel.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(); } } //15. 取消选择键 SelectionKey it.remove(); } } }
客户端流程
- 获取通道
SocketChannel sChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 9999));
- 切换非阻塞模式
sChannel.configureBlocking(false);
- 分配指定大小的缓冲区
ByteBuffer buf = ByteBuffer.allocate(1024);
- 发送数据给服务端
Scanner scan = new Scanner(System.in); while(scan.hasNext()){ String str = scan.nextLine(); buf.put((new SimpleDateFormat("yyyy/MM/dd HH:mm:ss").format(System.currentTimeMillis()) + "\n" + str).getBytes()); buf.flip(); sChannel.write(buf); buf.clear(); } //关闭通道 sChannel.close();
4.8 NIO非阻塞式网络通信入门案例
需求：服务端接收客户端的连接请求，并接收多个客户端发送过来的事件。
代码案例
/** 客户端 */ public class Client { public static void main(String[] args) throws Exception { //1. 获取通道 SocketChannel sChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 9999)); //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 Scanner scan = new Scanner(System.in); while(scan.hasNext()){ String str = scan.nextLine(); buf.put((new SimpleDateFormat("yyyy/MM/dd HH:mm:ss").format(System.currentTimeMillis()) + "\n" + str).getBytes()); buf.flip(); sChannel.write(buf); buf.clear(); } //5. 关闭通道 sChannel.close(); } } /** 服务端 */ public class Server { public static void main(String[] args) 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(9999)); //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) { System.out.println("轮一轮"); //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()) { //10. 若“接收就绪”，获取客户端连接 SocketChannel sChannel = ssChannel.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(); } } //15. 取消选择键 SelectionKey it.remove(); } } } }
