Netty 简单入门

Posted 2022-12-09 皓月行空

环境：netty-all-5.0.0.Alpha1.jar

坚持一下，把源码看完，勤奋一点，不要在懒惰了，你已经落下别人很多了

本文主要介绍Netty的简单入门

一、环境搭建

创建一个maven project，

修改pom.xml文件加载netty的jar 包

		<dependency>
		    <groupId>io.netty</groupId>
		    <artifactId>netty-all</artifactId> <!-- Use 'netty-all' for 4.0 or above -->
		    <version>5.0.0.Alpha1</version>
		    <scope>compile</scope>
		 </dependency>

二、编写客户端代码

package netty;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NiosocketChannel;

import java.io.UnsupportedEncodingException;
import java.util.logging.Logger;


public class TimeClient 
	public void connect(int port,String host)
		//配置客户端NIO线程组
		EventLoopGroup group=new NioEventLoopGroup();
		Bootstrap b=new Bootstrap();
		b.group(group).channel(NioSocketChannel.class)
			.option(ChannelOption.TCP_NODELAY, true)
			.handler(new ChannelInitializer<SocketChannel>() 
				protected void initChannel(SocketChannel ch) throws Exception 
					ch.pipeline().addLast(new TimeClientHandler());
				;
			);
		ChannelFuture f;
		try 
			f = b.connect(host, port).sync();//发起异步链接操作
			f.channel().closeFuture().sync();//等待客户端链路关闭
		 catch (InterruptedException e) 
			// TODO Auto-generated catch block
			e.printStackTrace();
		finally
			group.shutdownGracefully();//优雅关闭，释放NIO线程组
		
	
	public static void main(String[] args) 
		new TimeClient().connect(8080, "127.0.0.1");
	
	static class TimeClientHandler extends ChannelHandlerAdapter
		private static final Logger logger=Logger.getLogger(TimeClientHandler.class.getName());
		private int counter;
		private final ByteBuf firstMessage;
		private byte[] req;
		public TimeClientHandler() 
			// TODO Auto-generated constructor stub
			req=("Query time order"+System.getProperty("line.separator")).getBytes();
			firstMessage=Unpooled.buffer(req.length);
			firstMessage.writeBytes(req);
		
		//客户端与服务端链接建立，Netty的nio县城会调用channelActive方法,发送请求
		public void channelActive(ChannelHandlerContext ctx)
			ByteBuf message=null;
			for(int i=0;i<100;i++)
				message=Unpooled.buffer(req.length);
				message.writeBytes(req);
				ctx.writeAndFlush(message);
			
		
		//测试TCP 粘包拆包
		public void channelActive1(ChannelHandlerContext ctx)
			ByteBuf message=null;
			for(int i=0;i<100;i++)
				message=Unpooled.buffer(req.length);
				message.writeBytes(req);
				ctx.writeAndFlush(message);
			
		
		//当服务端返回response的时候，会调用channelRead方法
		public void channelRead(ChannelHandlerContext ctx ,Object msg)
			ByteBuf buf=(ByteBuf) msg;
			byte[]req=new byte[buf.readableBytes()];
			buf.readBytes(req);
			String body;
			try 
				body = new String(req,"UTF-8");
				System.out.println("Now is : "+body+" ; the counter is : "+ ++counter);
			 catch (UnsupportedEncodingException e) 
				// TODO Auto-generated catch block
				e.printStackTrace();
			
		
		public void exceptionCaught(ChannelHandlerContext ctx,Throwable cause)
			ctx.close();
		
	

三、编写服务端代码

package netty;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

import java.io.UnsupportedEncodingException;
import java.util.Date;



public class TimeServer 

	public static void main(String[] args) 
		// TODO Auto-generated method stub
		try 
			new TimeServer().bind(8080);
		 catch (Exception e) 
			// TODO Auto-generated catch block
			e.printStackTrace();
		
	
	public void bind(int port)throws Exception
		EventLoopGroup bossGroup=new NioEventLoopGroup();
		EventLoopGroup workerGroup =new NioEventLoopGroup();
		ServerBootstrap b=new ServerBootstrap();
		b.group(bossGroup, workerGroup)
			.channel(NioServerSocketChannel.class)
			.option(ChannelOption.SO_BACKLOG,1024)
			.childHandler(new ChildChannelHandler());
		ChannelFuture f=b.bind("127.0.0.1",port).sync();
		f.channel().closeFuture().sync();
	
	private class ChildChannelHandler extends ChannelInitializer<SocketChannel>

		@Override
		protected void initChannel(SocketChannel arg0) throws Exception 
			// TODO Auto-generated method stub
			arg0.pipeline().addLast(new TimeServerHandler());
		
		
	
	static class TimeServerHandler extends ChannelHandlerAdapter
		private  int  counter;
		public void channelRead(ChannelHandlerContext ctx,Object msg)
			ByteBuf buf=(ByteBuf) msg;
			byte[]req=new byte[buf.readableBytes()];
			buf.readBytes(req);
			try 
				String body=new String(req,"UTF-8");
				System.out.println("the time server receive order : "+body+" ; the counter is : "+ ++counter);
				String currentTime="Query time order".equalsIgnoreCase(body)?new Date(System.currentTimeMillis()).toString():"BAD ORDER";
				ByteBuf resp=Unpooled.copiedBuffer(currentTime.getBytes());
				ctx.write(resp);
			 catch (UnsupportedEncodingException e) 
				// TODO Auto-generated catch block
				e.printStackTrace();
			
			
		
		//测试
		public void channelRead2(ChannelHandlerContext ctx,Object msg)
			ByteBuf buf=(ByteBuf) msg;
			byte[]req=new byte[buf.readableBytes()];
			buf.readBytes(req);
			try 
				String body=new String(req,"UTF-8");
				System.out.println("the time server receive order : "+body+" ; the counter is : "+ ++counter);
				String currentTime="Query time order".equalsIgnoreCase(body)?new Date(System.currentTimeMillis()).toString():"BAD ORDER";
				ByteBuf resp=Unpooled.copiedBuffer(currentTime.getBytes());
				ctx.write(resp);
			 catch (UnsupportedEncodingException e) 
				// TODO Auto-generated catch block
				e.printStackTrace();
			
			
		
		public void channelReadComplete(ChannelHandlerContext ctx)
			ctx.flush();
		
		public void exceptionCaught(ChannelHandlerContext ctx,Throwable cause)
			ctx.close();