Netty框架实现TCP/IP通信的完美过程 Netty框架实现TCP

项目中需要使用到TCP/IP协议完成数据的发送与接收。如果只是用以前写的简单的socket套接字方法，每次接收发送消息都会创建新的socket再关闭socket，造成资源浪费。于是使用netty框架完成java网络通信。
Netty框架的内容很多，这里只是代码展示其中的一个功能。
代码仓库
这里使用的是Springboot+Netty框架，使用maven搭建项目。这里是在一个项目中搭建服务端与客户端，所以端口一样。还可以使用TCP/UTP工具自己搭建服务端和客户端，只要在yml文件中修改ip和端口就好。
pom.xml

4.0.0com.hzx.testmaven15nettytestmaven15netty1.0-SNAPSHOTorg.springframework.bootspring-boot-starter-parent2.3.0.RELEASEorg.springframework.bootspring-boot-starterio.nettynetty-all4.1.31.Final

application.yml

server:port: 8080# 作为客户端请求的服务端地址netty:tcp:server:# 作为客户端请求的服务端地址host: 127.0.0.1# 作为客户端请求的服务端端口port: 7000client:# 作为服务端开放给客户端的端口port: 7000

服务端

import io.netty.bootstrap.ServerBootstrap; 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.NioServerSocketChannel; import io.netty.util.concurrent.Future; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Value; import org.springframework.stereotype.Component; import java.util.Map; import java.util.concurrent.ConcurrentHashMap; @Componentpublic class NettyTcpServer {private static final Logger LOGGER = LoggerFactory.getLogger(NettyTcpServer.class); // boss事件轮询线程组// 处理Accept连接事件的线程，这里线程数设置为1即可，netty处理链接事件默认为单线程，过度设置反而浪费cpu资源private EventLoopGroup boss = new NioEventLoopGroup(1); //worker事件轮询线程组//处理handler的工作线程，其实也就是处理IO读写。线程数据默认为 CPU 核心数乘以2private EventLoopGroup worker = new NioEventLoopGroup(); @AutowiredServerChannelInitializer serverChannelInitializer; @Value("${netty.tcp.client.port}")private Integer port; // 与客户端建立连接后得到的通道对象private Channel channel; /*** 存储client的channel* key:ip value:Channel*/public static Map map = new ConcurrentHashMap(); /*** 开启Netty tcp server服务** @return*/public ChannelFuture start() {// 启动类ServerBootstrap serverBootstrap = new ServerBootstrap(); serverBootstrap.group(boss, worker)//组配置，初始化ServerBootstrap的线程组.channel(NioServerSocketChannel.class)//构造channel通道工厂 bossGroup的通道，只是负责连接.childHandler(serverChannelInitializer) //设置通道处理者ChannelHandlerWorkerGroup的处理器.option(ChannelOption.SO_BACKLOG, 1024)//socket参数，当服务器请求处理程全满时，用于临时存放已完成三次握手请求的队列的最大长度。如果未设置或所设置的值小于1，Java将使用默认值50。.childOption(ChannelOption.SO_KEEPALIVE, true); //启用心跳保活机制，tcp，默认2小时发一次心跳//Future：异步任务的生命周期，可用来获取任务结果ChannelFuture channelFuture1 = serverBootstrap.bind(port).syncUninterruptibly(); // 绑定端口开启监听同步等待if (channelFuture1 != null && channelFuture1.isSuccess()) {channel = channelFuture1.channel(); // 获取通道LOGGER.info("Netty tcp server start success,port={}",port); }else {LOGGER.error("Netty tcp server start fail"); }return channelFuture1; }/*** 停止Netty tcp server服务*/public void destroy(){if (channel != null) {channel.close(); }try {Future future = worker.shutdownGracefully().await(); if (!future.isSuccess()) {LOGGER.error("netty tcp workerGroup shutdown fail,{}",future.cause()); }} catch (InterruptedException e) {LOGGER.error(e.toString()); }LOGGER.info("Netty tcp server shutdown success"); }}

import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; import io.netty.handler.codec.string.StringDecoder; import io.netty.handler.codec.string.StringEncoder; import io.netty.handler.timeout.IdleStateHandler; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import java.util.concurrent.TimeUnit; @Componentpublic class ServerChannelInitializer extends ChannelInitializer {@AutowiredServerChannelHandler serverChannelHandler; @Overrideprotected void initChannel(SocketChannel socketChannel) throws Exception {ChannelPipeline pipeline = socketChannel.pipeline(); //IdleStateHandler心跳机制,如果超时触发Handle中userEventTrigger()方法pipeline.addLast("idleStateHandler",new IdleStateHandler(15,0,0, TimeUnit.MINUTES)); // 字符串编解码器pipeline.addLast(new StringDecoder(),new StringEncoder()); // 自定义Handlerpipeline.addLast("serverChannelHandler",serverChannelHandler); }}

import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.timeout.IdleState; import io.netty.handler.timeout.IdleStateEvent; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Component; @Component@ChannelHandler.Sharablepublic class ServerChannelHandler extends SimpleChannelInboundHandler