Netty 4.x Netty 实现简易聊天功能

1、环境准备

准备
JDK 8+
Maven 3.2.x
Netty 4.x
Eclipse IDE for Eclipse Committers

2、功能代码

2.1服务端

package com.moreday.netty_simplechat;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

/**
 * @ClassName SimpleChatServer
 * @Description TODO(这里用一句话描述这个类的作用)
 * @author 寻找手艺人
 * @Date 2020年4月16日 上午10:21:03
 * @version 1.0.0
 */
public class SimpleChatServer {
	private int port;

	/**
	 * @Description TODO(这里用一句话描述这个方法的作用)
	 */
	public SimpleChatServer(int port) {
		// TODO Auto-generated constructor stub
		this.port = port;
	}
	
	public void run() throws Exception {
		//配置NIO线程组
		EventLoopGroup bossGroup = new NioEventLoopGroup();
		EventLoopGroup workerGroup = new NioEventLoopGroup();
		
		try {
			ServerBootstrap b = new ServerBootstrap();
			b.group(bossGroup, workerGroup)
			.channel(NioServerSocketChannel.class)
			.option(ChannelOption.SO_BACKLOG,100)
			.handler(new LoggingHandler(LogLevel.INFO))
			.childHandler(new SimpleChatServerInitializer())
			.childOption(ChannelOption.SO_KEEPALIVE,true);
			
			System.out.println("SimpleChatServer 启动成功 ");
			
			//绑定端口，开始接收进来的链接
			ChannelFuture f = b.bind(port).sync();
			//等待服务器socket关闭，本例不会发生
			f.channel().closeFuture().sync();
			
		} finally {
			//优雅关闭
			bossGroup.shutdownGracefully();
			workerGroup.shutdownGracefully();
			
			System.out.println("SimpleChatServer 优雅关闭");
		}
	}
	

	public static void main(String[] args) throws Exception {
		int port = 8080;
		if(args!=null && args.length>0) {
			port = Integer.valueOf(args[0]);
		}
		new SimpleChatServer(port).run();
	}
}

package com.moreday.netty_simplechat;

import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;

/**
 * @ClassName SimpleChatServerHandler
 * @Description TODO(这里用一句话描述这个类的作用)
 * @author 寻找手艺人
 * @Date 2020年4月16日 上午10:12:57
 * @version 1.0.0
 */
public class SimpleChatServerHandler extends SimpleChannelInboundHandler<String>{

	
	private ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
	
	
	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.ChannelHandlerAdapter#handlerAdded(io.netty.channel.ChannelHandlerContext)
	 */
	@Override
	public void handlerAdded(ChannelHandlerContext ctx) throws Exception {
		// TODO Auto-generated method stub
	    Channel incoming =  ctx.channel();
	    for(Channel channel: channels) {
	    	channel.writeAndFlush("[Server]-"+incoming.remoteAddress()+"加入 \n");
	    }
	    channels.add(incoming);
	}
	
	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.ChannelHandlerAdapter#handlerRemoved(io.netty.channel.ChannelHandlerContext)
	 */
	@Override
	public void handlerRemoved(ChannelHandlerContext ctx) throws Exception {
		// TODO Auto-generated method stub
		Channel incoming = ctx.channel();
		for(Channel channel:channels) {
			channel.writeAndFlush("【Server】- "+incoming.remoteAddress()+"离开 \n");
		}
		channels.remove(incoming);
	}
	
	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.ChannelInboundHandlerAdapter#channelActive(io.netty.channel.ChannelHandlerContext)
	 */
	@Override
	public void channelActive(ChannelHandlerContext ctx) throws Exception {
		// TODO Auto-generated method stub
		Channel incoming = ctx.channel();
		System.out.println("SimpleChatClient"+incoming.remoteAddress()+"在线"+channels.size());
	}
	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.SimpleChannelInboundHandler#channelRead0(io.netty.channel.ChannelHandlerContext, java.lang.Object)
	 */
	@Override
	protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
		// TODO Auto-generated method stub
		Channel incoming = ctx.channel();
		for(Channel channel:channels) {
			if(channel!=incoming) {
				channel.writeAndFlush("["+incoming.remoteAddress()+"]"+msg+" \n");
				System.out.println("[Server Read]"+msg);
			}else {
				incoming.writeAndFlush("[self-]"+msg+"\n");
			}
		}
	}
	
	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.ChannelInboundHandlerAdapter#channelInactive(io.netty.channel.ChannelHandlerContext)
	 */
	@Override
	public void channelInactive(ChannelHandlerContext ctx) throws Exception {
		// TODO Auto-generated method stub
		Channel incoming = ctx.channel();
		System.out.println("SimpleChatClient"+incoming.remoteAddress()+"掉线");
	}
	
	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.ChannelInboundHandlerAdapter#exceptionCaught(io.netty.channel.ChannelHandlerContext, java.lang.Throwable)
	 */
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
		// TODO Auto-generated method stub
		Channel incoming = ctx.channel();
		System.out.println("SimpleChatClient"+incoming.remoteAddress()+"异常");
		cause.printStackTrace();
		ctx.close();
	}
	
	

}

package com.moreday.netty_simplechat;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.Delimiters;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

/**
 * @ClassName SimpleChatServerInitializer
 * @Description TODO(这里用一句话描述这个类的作用)
 * @author 寻找手艺人
 * @Date 2020年4月16日 上午10:20:20
 * @version 1.0.0
 */
public class SimpleChatServerInitializer extends ChannelInitializer<SocketChannel> {

	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.ChannelInitializer#initChannel(io.netty.channel.Channel)
	 */
	@Override
	protected void initChannel(SocketChannel ch) throws Exception {
		ChannelPipeline pipeline = ch.pipeline();

        pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
        pipeline.addLast("decoder", new StringDecoder());
        pipeline.addLast("encoder", new StringEncoder());
        pipeline.addLast("handler", new SimpleChatServerHandler());

        System.out.println("SimpleChatClient:"+ch.remoteAddress() +"连接上");
	}

}

2.2客户端

package com.moreday.netty_simplechat;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
 
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;

/**
 * @ClassName SimpleChatClient
 * @Description TODO(这里用一句话描述这个类的作用)
 * @author 寻找手艺人
 * @Date 2020年4月16日 上午10:21:54
 * @version 1.0.0
 */
public class SimpleChatClient {
	private final int port;
	private final String host;

	/**
	 * @Description TODO(这里用一句话描述这个方法的作用)
	 */
	public SimpleChatClient(int port, String host) {
		// TODO Auto-generated constructor stub
		this.port = port;
		this.host = host;
	}
	
	public void connect() throws InterruptedException, IOException {
		EventLoopGroup group = new NioEventLoopGroup();
		try {
			Bootstrap b = new Bootstrap();
			b.group(group)
			.channel(NioSocketChannel.class)
			.handler(new SimpleChatClientInitializer());
			
			Channel  channel = b.connect(host,port).sync().channel();
			BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
			while(true) {
				channel.writeAndFlush(in.readLine()+"\r\n");
			}
			
		} finally {
			// TODO: handle finally clause
			group.shutdownGracefully();
		}
		
	}
	
	public static void main(String[] args) throws Exception {
		int port = 8080;
		if(args!=null && args.length>0) {
			port = Integer.valueOf(args[0]);
		}
		new SimpleChatClient(port, "localhost").connect();
	}
}

package com.moreday.netty_simplechat;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

/**
 * @ClassName SimpleChatClientHandler
 * @Description TODO(这里用一句话描述这个类的作用)
 * @author 寻找手艺人
 * @Date 2020年4月16日 上午10:21:21
 * @version 1.0.0
 */
public class SimpleChatClientHandler extends SimpleChannelInboundHandler<String>{

	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.SimpleChannelInboundHandler#channelRead0(io.netty.channel.ChannelHandlerContext, java.lang.Object)
	 */
	@Override
	protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
		// TODO Auto-generated method stub
		System.out.println(msg);
	}

}

package com.moreday.netty_simplechat;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.Delimiters;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;

/**
 * @ClassName SimpleChatClientInitializer
 * @Description TODO(这里用一句话描述这个类的作用)
 * @author 寻找手艺人
 * @Date 2020年4月16日 上午10:21:35
 * @version 1.0.0
 */
public class SimpleChatClientInitializer extends ChannelInitializer<SocketChannel>{

	/* (非 Javadoc)
	 * Description:
	 * @see io.netty.channel.ChannelInitializer#initChannel(io.netty.channel.Channel)
	 */
	@Override
	protected void initChannel(SocketChannel ch) throws Exception {
		// TODO Auto-generated method stub
	        ChannelPipeline pipeline = ch.pipeline();
	        pipeline.addLast(new LoggingHandler(LogLevel.INFO));
	        pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
	        pipeline.addLast("decoder", new StringDecoder());
	        pipeline.addLast("encoder", new StringEncoder());
	        pipeline.addLast("handler", new SimpleChatClientHandler());
	    }
}

2.3运行结果

---

到此，Netty 4.x Netty 实现聊天功能已开发完成。下篇博文我们来学习一下HTTP协议开发应用