本文源码：https://github.com/axin1240101543/netty（有什么问题可以提issue给我，一起学习，共同进步。）
1、聊天室服务端
package com.darren.service.netty.netty.chat;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.concurrent.GlobalEventExecutor;
import java.text.SimpleDateFormat;
import java.util.Date;
/**
* <h3>netty</h3>
* <p></p>
*
* @author : Darren
* @date : 2021年05月26日 07:19:54
**/
public class ChatServer {
public static void main(String[] args) throws InterruptedException {
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup(8);
try {
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_BACKLOG, 1024)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
//加入特殊分隔符分包解码器
ChannelPipeline pipeline = socketChannel.pipeline();
/*pipeline.addLast(new DelimiterBasedFrameDecoder(
1024, Unpooled.copiedBuffer("_".getBytes())));*/
//向pipeline加入解码器
pipeline.addLast("decoder", new StringDecoder());
//向pipeline加入编码器
pipeline.addLast("encoder", new StringEncoder());
//加入自己的业务处理handler
pipeline.addLast(new ChatServerHandler());
}
});
System.out.println("聊天室server启动...");
ChannelFuture channelFuture = bootstrap.bind(8080).sync();
//关闭通道
channelFuture.channel().closeFuture().sync();
}finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
/**
* 业务处理handler
*/
static class ChatServerHandler extends SimpleChannelInboundHandler<String> {
//GlobalEventExecutor.INSTANCE 是全局的事件执行器，是一个单例
private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
/**
* 表示channel处于就绪状态，表示上线
* @param ctx
* @throws Exception
*/
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
//将该客户加入聊天的信息推送给其他在线的客户端
//该方法会将channelGroup中所有的channel遍历，并发送消息
channelGroup.writeAndFlush("[客户端]" + channel.remoteAddress() + "上线了 "
+ sdf.format(new Date()) + "\n");
channelGroup.add(channel);
System.out.println(ctx.channel().remoteAddress() + "上线了" + "\n");
}
/**
* 表示channel处于不活动状态，提示离线了
* @param ctx
* @throws Exception
*/
@Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
Channel channel = ctx.channel();
//将客户离开信息推送给当前在线的客户
channelGroup.writeAndFlush("[ 客户端 ]" + channel.remoteAddress() + " 下线了" + "\n");
System.out.println(ctx.channel().remoteAddress() + " 下线了" + "\n");
System.out.println("channelGroup size=" + channelGroup.size());
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
//获取到当前的channel
Channel channel = ctx.channel();
//这是我们遍历channelGroup，根据不同的请求，回送不同的消息
channelGroup.forEach(ch -> {
if (channel != ch){//不是当前的channel，转发消息
ch.writeAndFlush("[客户端]"
+ channel.remoteAddress() + " 发送了消息：" + msg + "\n");
}else {//回显自己发送的消息给自己
ch.writeAndFlush("[自己]发送了消息：" + msg + "\n");
}
});
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
ctx.close();
}
}
}
二、聊天室客户端
package com.darren.service.netty.netty.chat;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import java.util.Scanner;
/**
* <h3>netty</h3>
* <p></p>
*
* @author : Darren
* @date : 2021年05月26日 07:34:58
**/
public class ChatClient {
public static void main(String[] args) throws InterruptedException {
//客户端需要一个事件循环组
EventLoopGroup group = new NioEventLoopGroup();
try {
//创建客户端启动对象
//注意客户端使用的不是ServerBootstrap，而是Bootstrap
Bootstrap bootstrap = new Bootstrap();
//设置相关参数
bootstrap.group(group)//设置线程组
//使用NioSocketChannel作为客户端的通道实现
.channel(NioSocketChannel.class)
.handler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel socketChannel) throws Exception {
//加入特殊分隔符分包解码器
ChannelPipeline pipeline = socketChannel.pipeline();
/*pipeline.addLast(new DelimiterBasedFrameDecoder(
1024, Unpooled.copiedBuffer("_".getBytes())));*/
//向pipeline加入解码器
pipeline.addLast("decoder", new StringDecoder());
//向pipeline加入编码器
pipeline.addLast("encoder", new StringEncoder());
//加入自己的业务处理handler
pipeline.addLast(new ChatClientHandler());
}
});
System.out.println("netty client start");
ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 8080).sync();
//得到channel
Channel channel = channelFuture.channel();
System.out.println("===========" + channel.localAddress() + "================");
//客户端需要输入信息，创建一个扫描器
Scanner scanner = new Scanner(System.in);
while (scanner.hasNextLine()){
String msg = scanner.nextLine();
//通过channel发送到服务器端
channel.writeAndFlush(msg);
}
}finally {
group.shutdownGracefully();
}
}
static class ChatClientHandler extends SimpleChannelInboundHandler<String>{
@Override
protected void channelRead0(ChannelHandlerContext channelHandlerContext, String msg) throws Exception {
System.out.println(msg.trim());
}
}
}