Netty简介 Netty线程模型和EventLoop Codec编码与解码 ByteBuf容器

package com.github.guang19.nettylearning.nio_chat; import java.io.IOException; import java.net.InetSocketAddress; import java.nio.ByteBuffer; import java.nio.channels.*; import java.nio.charset.StandardCharsets; import java.util.Iterator; import java.util.Scanner; import java.util.Set; /** * @author guang19 * @date 2020/6/2 * @description 基于NIO的聊天室的客户端 * @since 1.0.0 */ public class ChatClient { //服务端的ip和port private final String serverAddr = "127.0.0.1"; private final int serverPort = 10000; public ChatClient(){} public void start() { try( SocketChannel clientSocketChannel = bindSocketChannel(); Selector selector = connectServer(clientSocketChannel);) { System.out.println("client start connect..."); listen(selector,clientSocketChannel); System.out.println("client stop connect..."); } catch (IOException e) { e.printStackTrace(); } } private SocketChannel bindSocketChannel() throws IOException { SocketChannel socketChannel = SocketChannel.open(); socketChannel.configureBlocking(false); return socketChannel; } //初始化server socket channel private Selector connectServer(SocketChannel clientSocketChannel) throws IOException { Selector selector = registerSelectableChannel(null,clientSocketChannel, SelectionKey.OP_CONNECT); clientSocketChannel.connect(new InetSocketAddress(serverAddr,serverPort)); return selector; } //将channel注册到selector private Selector registerSelectableChannel(Selector selector, SelectableChannel selectableChannel, int nextOp) throws IOException { if (selector == null) { selector = Selector.open(); } selectableChannel.configureBlocking(false); selectableChannel.register(selector,nextOp); return selector; } public void listen(Selector selector,SocketChannel socketChannel) throws IOException { new Thread(new SocketChannelReader(selector)).start(); sendMsgToSocketChannel(socketChannel); } private void sendMsgToSocketChannel(SocketChannel socketChannel) throws IOException { ByteBuffer byteBuffer = null; try { Scanner scanner = new Scanner(System.in); System.out.print("请输入: "); while (scanner.hasNextLine()) { System.out.print("请输入: "); String input = scanner.nextLine(); socketChannel.write(byteBuffer = ByteBuffer.wrap(input.getBytes(StandardCharsets.UTF_8))); byteBuffer.clear(); } } catch (IOException e) { throw new IOException(e); } finally { if (byteBuffer != null) { byteBuffer.clear(); byteBuffer = null; } } } private class SocketChannelReader extends Thread { //单独开一个线程读取数据 private Selector selector; public SocketChannelReader(Selector selector) { this.selector = selector; } @Override public void run() { try { while (true) { int isEvent = selector.select(); if (isEvent <= 0) { continue; } Set<SelectionKey> selectionKeys = selector.selectedKeys(); Iterator<SelectionKey> selectionKeyIterator = selectionKeys.iterator(); SelectionKey selectionKey = null; while (selectionKeyIterator.hasNext()) { selectionKey = selectionKeyIterator.next(); //client socket channel connect server if (selectionKey.isConnectable()) { SocketChannel clientSocketChannel = (SocketChannel) selectionKey.channel(); //完成连接过程 clientSocketChannel.finishConnect(); registerSelectableChannel(selector, clientSocketChannel, SelectionKey.OP_READ); } //server socket channel can write else if (selectionKey.isReadable()) { SocketChannel clientSocketChannel = (SocketChannel) selectionKey.channel(); readDataFromSocketChannel(selector, clientSocketChannel); registerSelectableChannel(selector, clientSocketChannel, SelectionKey.OP_READ); } selectionKeyIterator.remove(); } } } catch (IOException e) { e.printStackTrace(); } } //从 socket channel 读取数据 private void readDataFromSocketChannel(Selector selector, SocketChannel socketChannel) throws IOException { ByteBuffer byteBuffer = ByteBuffer.allocate(1024); StringBuilder data = new StringBuilder(); int count = 0; try { while ((count = socketChannel.read(byteBuffer)) > 0) { byteBuffer.flip(); byte[] bytes = new byte[count]; byteBuffer.get(bytes); byteBuffer.clear(); data.append(new String(bytes,StandardCharsets.UTF_8)); ++count; } System.out.println(data); } catch (IOException e) { throw new IOException(e); } finally { byteBuffer.clear(); } } } public static void main(String[] args) throws Exception { ChatClient chatClient = new ChatClient(); chatClient.start(); } }