1. netty简介
Netty是一个异步事件驱动的网络应用框架，可快速开发可维护的高性能协议服务器和客户端。基于NIO实现的高性能网络IO框架，极大简化基于常用网络协议的编程（TCP、UDP等）。
2. reactor主从架构图
3. 开始实现一个tcp的服务端
3.1 配置文件
tcpServer.port=8899
3.2 nettyTcpServer代码实现
package com.zkzp.eage.netty.server;
import com.zkzp.eage.netty.handle.HeatBeatHandler;
import com.zkzp.eage.netty.handle.NettyServerHandler;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.util.concurrent.Future;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import java.util.concurrent.TimeUnit;
@Slf4j
@Component
public class NettyTcpServer {
@Value("${tcpServer.port}")
private int tcpServerPort;
@Autowired
private NettyServerHandler nettyServerHandler;
private static boolean isStart = false;
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
NioEventLoopGroup workerGroup = new NioEventLoopGroup();
public boolean serverStart(){
try{
if(isStart) return true;
ServerBootstrap bootstrap = new ServerBootstrap();
bootstrap.group(bossGroup, workerGroup);
bootstrap.option(ChannelOption.SO_BACKLOG, 2048).option(ChannelOption.SO_REUSEADDR, true).childOption(ChannelOption.SO_KEEPALIVE, true);
bootstrap.channel(NioServerSocketChannel.class);
ChannelInitializer<SocketChannel> channelChannelInitializer = new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel channel) throws Exception {
ChannelPipeline pipeline = channel.pipeline();
pipeline.addLast(new IdleStateHandler(40, 0, 0, TimeUnit.MINUTES));
pipeline.addLast(new HeatBeatHandler());
pipeline.addLast(new LineBasedFrameDecoder(1024));
pipeline.addLast(new StringDecoder());
pipeline.addLast(new StringEncoder());
pipeline.addLast(nettyServerHandler);
}
};
bootstrap.childHandler(channelChannelInitializer);
ChannelFuture channelFuture = bootstrap.bind(tcpServerPort).sync();
log.info("Netty Tcp Server start success on port：{}", tcpServerPort);
isStart = true;
return true;
}catch(Exception e){
e.printStackTrace();
return false;
}
}
public synchronized boolean serverStop() {
try {
if (!isStart) return true;
Future<?> future = this.workerGroup.shutdownGracefully().await();
if (!future.isSuccess()) {
log.error("<---- netty workerGroup cannot be stopped", future.cause());
return false;
}
future = this.bossGroup.shutdownGracefully().await();
if (!future.isSuccess()) {
log.error("<---- netty bossGroup cannot be stopped", future.cause());
return false;
}
log.info("关闭Netty Tcp 服务端成功");
isStart = false;
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
}
}
}
3.3 心跳handle代码实现
package com.zkzp.eage.netty.handle;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
public class HeatBeatHandler extends ChannelInboundHandlerAdapter {
@Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
if (!(evt instanceof IdleStateEvent)) {
super.userEventTriggered(ctx, evt);
return;
}
if (((IdleStateEvent) evt).state() == IdleState.READER_IDLE) {
ctx.disconnect();
}
}
}
3.4 业务handle代码实现
package com.zkzp.eage.netty.handle;
import io.netty.channel.Channel;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import java.net.InetSocketAddress;
import java.util.concurrent.ConcurrentHashMap;
@Slf4j
@Component
@ChannelHandler.Sharable
public class NettyServerHandler extends ChannelInboundHandlerAdapter {
private static final ConcurrentHashMap<String, ChannelHandlerContext> CHANNEL_MAP = new ConcurrentHashMap<>();
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
//在这里做业务处理
System.out.println("----------------"+msg.toString());
}
@Override
public void channelActive(ChannelHandlerContext ctx) {
InetSocketAddress insocket = (InetSocketAddress) ctx.channel().remoteAddress();
String channelId = ctx.channel().id().asLongText();
if (!CHANNEL_MAP.containsKey(channelId)) {
CHANNEL_MAP.put(channelId, ctx);
log.info("新的连接加入了：[{}]", channelId);
}
}
@Override
public void channelInactive(ChannelHandlerContext ctx) {
String channelId = ctx.channel().id().asLongText();
if (CHANNEL_MAP.containsKey(channelId)) {
//删除连接
CHANNEL_MAP.remove(channelId);
log.info("连接已断开：[{}]", channelId);
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
super.exceptionCaught(ctx, cause);
Channel channel = ctx.channel();
if (channel.isActive()) {
ctx.close();
}
}
}
4. 使用tcp工具进行测试
4.1 创建客户端 连接nettyTcpServer的8899端口
文章来源：https://www.toymoban.com/news/detail-587687.html
4.2 点击连接
文章来源地址https://www.toymoban.com/news/detail-587687.html
4.3 给服务端发送消息，看服务端是否接收到
2022-09-28 16:49:21.491 INFO 8516 --- [ main] c.zkzp.eage.netty.server.NettyTcpServer : Netty Tcp Server start success on port：8899
2022-09-28 16:49:27.460 INFO 8516 --- [ntLoopGroup-3-1] c.z.e.netty.handle.NettyServerHandler : 新的连接加入了：[e00af6fffeb19725-00002144-00000001-28bb7b3a64721f9d-58f4af16]
----------------hello
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