读书笔记：《netty 权威指南》和 《netty 4核心原理》学习demo.zip

package NIO; import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.channels.SelectionKey; import java.nio.channels.Selector; import java.nio.channels.ServerSocketChannel; import java.nio.channels.SocketChannel; import java.util.Date; import java.util.Iterator; import java.util.Set; /** * @author lijiangtao * @description 多路复用类 * @date 2020/9/23 */ public class MultiplexerTimeServer implements Runnable{ private Selector selector; private ServerSocketChannel serverSocketChannel; private volatile boolean stop; public MultiplexerTimeServer(int port){ try { selector = Selector.open(); serverSocketChannel = ServerSocketChannel.open(); serverSocketChannel.configureBlocking(false); serverSocketChannel.socket().bind(new InetSocketAddress(port),1024); serverSocketChannel.register(selector,SelectionKey.OP_ACCEPT); System.out.println("time server is start in port:"+port); }catch (Exception e){ e.printStackTrace(); System.exit(1); } } @Override public void run() { while (!stop){ try { selector.select(100); Set<SelectionKey> selectionKeys = selector.selectedKeys(); Iterator<SelectionKey> iterator = selectionKeys.iterator(); SelectionKey key = null; while (iterator.hasNext()){ key = iterator.next(); iterator.remove(); try { this.handleInput(key); }catch (Exception e){ if(key != null){ key.cancel(); if(key.channel() != null){ key.channel().close(); } } } } } catch (IOException e) { e.printStackTrace(); } } if (selector != null){ try { //多路复用器selector 关闭后，上面注册的channel 和 pipe 等资源会自动关闭，释放资源 selector.close(); } catch (IOException e) { e.printStackTrace(); } } } public void stop(){ this.stop = true; } private void handleInput(SelectionKey key) throws IOException { if(key.isValid()){ if (key.isAcceptable()) { //处理新连接 相当于完成tcp三次握手 ServerSocketChannel ssc = (ServerSocketChannel) key.channel(); SocketChannel sc = ssc.accept(); sc.configureBlocking(false); //创建一个新的链接到selector sc.register(selector,SelectionKey.OP_READ); } if (key.isReadable()) { SocketChannel socketChannel = (SocketChannel) key.channel(); ByteBuffer readBuffer = ByteBuffer.allocate(1024); int read = socketChannel.read(readBuffer); if (read > 0){ readBuffer.flip(); byte[] bytes = new byte[readBuffer.remaining()]; readBuffer.get(bytes); String body =new String(bytes, "UTF-8"); System.out.println("the time server receiver order :"+body); String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body)?new Date().toString():"BAD ORDER"; this.doWrite(socketChannel,currentTime); }else if(read < 0){ key.cancel(); socketChannel.close(); }else { ;//读取到 0 字节 } } } } private void doWrite(SocketChannel channel,String response) throws IOException { if(response != null && response.length() > 0){ byte[] bytes = response.getBytes(); ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length); writeBuffer.put(bytes); writeBuffer.flip(); channel.write(writeBuffer); } } }