标签：remove 逻辑 pac 客户端 cto oid util imp 数据读取
本案例来源于《netty权威指南》
1 public class Server { 2 public static void main(String[] args) throws IOException { 3 new Thread(new ServerHandler(8080), "server-1").start(); 4 } 5 }
创建一个任务ServerHandler，然后创建一条线程，启动执行该任务。
1 public class ServerHandler implements Runnable { 2 private Selector selector; 3 private ServerSocketChannel ssChannel; 4 5 public ServerHandler(int port) { 6 try { 7 //等价于 Selector selector = SelectorProvider.provider().openSelector(); 8 selector = Selector.open(); 9 //等价于 SelectorProvider.provider().openServerSocketChannel() 10 ssChannel = ServerSocketChannel.open(); 11 ssChannel.configureBlocking(false); 12 ssChannel.bind(new InetSocketAddress(port), 1024); 13 ssChannel.register(selector, SelectionKey.OP_ACCEPT); 14 } catch (IOException e) { 15 e.printStackTrace(); 16 System.exit(1); 17 } 18 } 19 20 public void run() { 21 for (; ; ) { 22 try { 23 selector.select(); 24 Iterator<SelectionKey> it = selector.selectedKeys().iterator(); 25 while (it.hasNext()) { 26 SelectionKey key = it.next(); 27 it.remove(); 28 handleInput(key); 29 } 30 } catch (Throwable t) { 31 t.printStackTrace(); 32 } 33 } 34 35 } 36 37 private void handleInput(SelectionKey key) throws IOException { 38 if (key.isValid()) { 39 // 处理新接入的请求消息 40 if (key.isAcceptable()) { 41 // Accept the new connection 42 ServerSocketChannel ssc = (ServerSocketChannel) key.channel(); 43 SocketChannel sc = ssc.accept(); 44 sc.configureBlocking(false); 45 // Add the new connection to the selector 46 sc.register(selector, SelectionKey.OP_READ); 47 } 48 if (key.isReadable()) { 49 // Read the data 50 SocketChannel sc = (SocketChannel) key.channel(); 51 ByteBuffer readBuffer = ByteBuffer.allocate(1024); 52 int readBytes = sc.read(readBuffer); 53 if (readBytes > 0) { 54 readBuffer.flip(); 55 byte[] bytes = new byte[readBuffer.remaining()]; 56 readBuffer.get(bytes); 57 String body = new String(bytes, "UTF-8"); 58 System.out.println("The time server receive order : " 59 + body); 60 String currentTime = "QUERY TIME ORDER" 61 .equalsIgnoreCase(body) ? new java.util.Date( 62 System.currentTimeMillis()).toString() 63 : "BAD ORDER"; 64 doWrite(sc, currentTime); 65 } else if (readBytes < 0) { 66 // 对端链路关闭 67 key.cancel(); 68 sc.close(); 69 } else 70 ; // 读到0字节，忽略 71 } 72 } 73 } 74 75 private void doWrite(SocketChannel channel, String response) 76 throws IOException { 77 if (response != null && response.trim().length() > 0) { 78 byte[] bytes = response.getBytes(); 79 ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length); 80 writeBuffer.put(bytes); 81 writeBuffer.flip(); 82 channel.write(writeBuffer); 83 } 84 } 85 }
步骤：
1、创建一个Selector和ServerSocketChannel实例
2、配置ServerSocketChannel实例为非阻塞
3、ServerSocketChannel实例bind端口
4、将ServerSocketChannel实例注册到selector上，监听OP_ACCEPT事件
下面的任务在Server创建的新的线程中执行，不影响主线程执行其他逻辑
5、之后进入死循环
5.1、使用select.select()阻塞等待就绪事件（这里是等待OP_ACCEPT事件），一旦有有就绪事件到达，立即向下执行
5.2、使用selector.selectedKeys()获取已经就绪的SelectionKey（即OP_ACCEPT/OP_CONECT/OP_READ/OP_WRITE）集合，之后循环遍历
5.3、从迭代器删除该SelectionKey，防止下一次再被遍历到
5.4、如果SelectionKey==OP_ACCEPT，则通过ServerSocketChannel.accept()创建SocketChannel，该SocketChannel是后续真正的与客户端的SocketChannel进行通信的实体
5.5、配置新创建的SocketChannel实例为非阻塞，然后将该SocketChannel实例注册到selector实例上，监听OP_READ事件
5.6、等客户端发出请求数据时，此处监听到SelectionKey==OP_READ，则创建ByteBuffer实例，将SocketChannel中的数据读取到ByteBuffer中，然后再创建ByteBuffer将信息写回到SocketChannel（也就是说数据的读写一定要通过Buffer）
1 public class Client { 2 public static void main(String[] args) { 3 new Thread(new ClientHandler("127.0.0.1", 8080), "client-1").start(); 4 } 5 }
创建一个任务ClientHandler，然后创建一条线程，启动执行该任务。
1 public class ClientHandler implements Runnable { 2 private String host; 3 private int port; 4 5 private Selector selector; 6 private SocketChannel socketChannel; 7 8 public ClientHandler(String host, int port) { 9 this.host = host; 10 this.port = port; 11 try { 12 selector = Selector.open(); 13 socketChannel = SocketChannel.open(); 14 socketChannel.configureBlocking(false); 15 } catch (IOException e) { 16 e.printStackTrace(); 17 System.exit(1); 18 } 19 } 20 21 public void run() { 22 try { 23 doConnect(); 24 } catch (IOException e) { 25 e.printStackTrace(); 26 System.exit(1); 27 } 28 while (true) { 29 try { 30 selector.select(); 31 Iterator<SelectionKey> it = selector.selectedKeys().iterator(); 32 while (it.hasNext()) { 33 SelectionKey key = it.next(); 34 it.remove(); 35 handleInput(key); 36 } 37 } catch (Exception e) { 38 e.printStackTrace(); 39 System.exit(1); 40 } 41 } 42 } 43 44 private void handleInput(SelectionKey key) throws IOException { 45 if (key.isValid()) { 46 // 判断是否连接成功 47 SocketChannel sc = (SocketChannel) key.channel(); 48 if (key.isConnectable()) { 49 if (sc.finishConnect()) { 50 sc.register(selector, SelectionKey.OP_READ); 51 doWrite(sc); 52 } else 53 System.exit(1);// 连接失败，进程退出 54 } else if (key.isReadable()) { 55 ByteBuffer readBuffer = ByteBuffer.allocate(1024); 56 int readBytes = sc.read(readBuffer); 57 if (readBytes > 0) { 58 readBuffer.flip(); 59 byte[] bytes = new byte[readBuffer.remaining()]; 60 readBuffer.get(bytes); 61 String body = new String(bytes, "UTF-8"); 62 System.out.println("Now is : " + body); 63 } else if (readBytes < 0) { 64 // 对端链路关闭 65 key.cancel(); 66 sc.close(); 67 } else 68 ; // 读到0字节，忽略 69 } 70 } 71 72 } 73 74 private void doConnect() throws IOException { 75 // 如果直接连接成功，则注册到多路复用器上，发送请求消息，读应答 76 if (socketChannel.connect(new InetSocketAddress(host, port))) { 77 socketChannel.register(selector, SelectionKey.OP_READ); 78 doWrite(socketChannel); 79 } else 80 socketChannel.register(selector, SelectionKey.OP_CONNECT); 81 } 82 83 private void doWrite(SocketChannel sc) throws IOException { 84 byte[] req = "QUERY TIME ORDER".getBytes(); 85 ByteBuffer writeBuffer = ByteBuffer.allocate(req.length); 86 writeBuffer.put(req); 87 writeBuffer.flip(); 88 sc.write(writeBuffer); 89 if (!writeBuffer.hasRemaining()) 90 System.out.println("Send order 2 server succeed."); 91 } 92 }
步骤：
1、创建一个Selector和SocketChannel实例
2、配置SocketChannel实例为非阻塞
下面的任务在Cilent创建的新的线程中执行，不影响主线程执行其他逻辑
3、SocketChannel.connect连接到server端，如果连接没有马上成功，将该SocketChannel实例注册到selector上，监听OP_CONNECT事件；如果连接成功，将该SocketChannel实例注册到selector上，监听OP_READ事件，之后写数据给server端
4、之后进入死循环
4.1、使用select.select()阻塞等待就绪事件，一旦有有就绪事件到达，立即向下执行
4.2、使用selector.selectedKeys()获取已经就绪的SelectionKey（即OP_ACCEPT/OP_CONECT/OP_READ/OP_WRITE）集合，之后循环遍历
4.3、从迭代器删除该SelectionKey，防止下一次再被遍历到
4.4、如果SelectionKey==OP_CONNECT，将该SocketChannel实例注册到selector上，监听OP_READ事件，之后写数据给server端；如果监听到SelectionKey==OP_READ，则创建ByteBuffer实例，将SocketChannel中的数据读取到ByteBuffer中
标签：remove 逻辑 pac 客户端 cto oid util imp 数据读取
原文地址：https://www.cnblogs.com/java-zhao/p/9195943.html
