SpringBoot整合Netty实现TCP通信

SpringBoot整合Netty，实现TCP通信

1. 组成部分为：SpringBoot + Mybatis + netty；

2. 开发环境为Java8 ，IDEA，Maven；

3. 开始教程

   1. 使用 idea 创建 SpringBoot 项目；

   2. 创建完成后在 pom.xml 文件 dependencies 写入以下代码：

       
              <dependency>
                  <groupId>io.nettygroupId>
                  <artifactId>netty-allartifactId>
                  <version>4.1.17.Finalversion>
              dependency>
      

   3. 创建三个 Netty 所需类

      1. NettyServer 为服务器监听器

         package cn.han.han_parse.service;
         
         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 lombok.extern.slf4j.Slf4j;
         
         import java.net.InetSocketAddress;
         
         /**
          * @author hanyiming
          * @create 2021/9/9 10:08
          */
         @Slf4j
         public class NettyServer {
             public void start() {
                 System.out.println("这是Netty");
                 InetSocketAddress socketAddress = new InetSocketAddress("127.0.0.1", 8080);
                 //new 一个主线程组
                 EventLoopGroup bossGroup = new NioEventLoopGroup(1);
                 //new 一个工作线程组
                 EventLoopGroup workGroup = new NioEventLoopGroup(200);
                 ServerBootstrap bootstrap = new ServerBootstrap()
                         .group(bossGroup, workGroup)
                         .channel(NioServerSocketChannel.class)
                         .childHandler(new ServerChannelInitializer())
                         .localAddress(socketAddress)
                         //设置队列大小
                         .option(ChannelOption.SO_BACKLOG, 1024)
                         // 两小时内没有数据的通信时,TCP会自动发送一个活动探测数据报文
                         .childOption(ChannelOption.SO_KEEPALIVE, true);
                 //绑定端口,开始接收进来的连接
                 try {
                     ChannelFuture future = bootstrap.bind(socketAddress).sync();
                     log.info("服务器启动开始监听端口: {}", socketAddress.getPort());
                     future.channel().closeFuture().sync();
                 } catch (InterruptedException e) {
                     log.error("服务器开启失败", e);
                 } finally {
                     //关闭主线程组
                     bossGroup.shutdownGracefully();
                     //关闭工作线程组
                     workGroup.shutdownGracefully();
                 }
             }
         }
         
         

      2. NettyServerHandler 为处理器

         • 注意在此处如果没写Controller层，需要在本类中添加@Component 注解，并初始化所需要的service层和mapper层；如果不需要可以删除，在以下代码中有@Component 注解；

         package cn.han.han_parse.service;
         
         import cn.han.han_parse.dao.BasicMapper;
         import cn.han.han_parse.entity.Basic;
         import cn.han.han_parse.util.ParseMessage;
         import io.netty.channel.ChannelHandlerContext;
         import io.netty.channel.ChannelInboundHandlerAdapter;
         import lombok.extern.slf4j.Slf4j;
         import org.springframework.beans.factory.annotation.Autowired;
         import org.springframework.stereotype.Component;
         
         import javax.annotation.PostConstruct;
         
         /**
          * @author hanyiming
          * @create 2021/9/9 10:12
          */
         @Slf4j
         @Component
         public class NettyServerHandler extends ChannelInboundHandlerAdapter {
         
             public static NettyServerHandler nettyServerHandler;
         
             @Autowired
             private BasicService basicService;
         
             @Autowired
             private BasicMapper basicMapper;
         
             @PostConstruct
             public void init() {
                 nettyServerHandler = this;
                 nettyServerHandler.basicService = this.basicService;
                 nettyServerHandler.basicMapper = this.basicMapper;
                 // 初使化时将已静态化的testService实例化
             }
         
             /**
              * 客户端连接会触发
              */
             @Override
             public void channelActive(ChannelHandlerContext ctx) throws Exception {
                 log.info("连接成功...");
             }
         
             /**
              * 客户端发消息会触发
              */
             @Override
             public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
                 log.info("服务器收到消息: {}", msg.toString());
                 //此处为解析tcp参数所需要的方法！！！自定义
                 /*final Basic parse = ParseMessage.parse(ctx, msg.toString());
                 nettyServerHandler.basicService.addBasic(parse);*/
                 ctx.write("你也好哦");
                 ctx.flush();
             }
         
         
             /**
              * 发生异常触发
              */
             @Override
             public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
                 cause.printStackTrace();
                 ctx.close();
             }
         }
         
         

      3. ServerChannelInitializer 服务初始化器，

         package cn.han.han_parse.service;
         
         import cn.han.han_parse.util.MyDecode;
         import io.netty.channel.ChannelInitializer;
         import io.netty.channel.socket.SocketChannel;
         import io.netty.handler.codec.string.StringDecoder;
         import io.netty.handler.codec.string.StringEncoder;
         import io.netty.util.CharsetUtil;
         import lombok.extern.slf4j.Slf4j;
         
         /**
          * @author hanyiming
          * @create 2021/9/9 10:10
          */
         @Slf4j
         public class ServerChannelInitializer extends ChannelInitializer<SocketChannel> {
         
             @Override
             protected void initChannel(SocketChannel socketChannel) throws Exception {
                 //添加编解码，此处代码为解析tcp传过来的参数，为UTF-8格式，可以自定义解码格式
                 socketChannel.pipeline().addLast("decoder", new StringDecoder(CharsetUtil.UTF_8));
                 socketChannel.pipeline().addLast("encoder", new StringEncoder(CharsetUtil.UTF_8));
                 socketChannel.pipeline().addLast(new NettyServerHandler());
             }
         }
         
         

      4. 此处为我所需的进制转换规则：

          /**
              * 十六进制转换为十进制
              *
              * @param content
              * @return
              */
             public static int covert(String content) {
                 int number = 0;
                 String[] HighLetter = {"A", "B", "C", "D", "E", "F"};
                 Map<String, Integer> map = new HashMap<>();
                 for (int i = 0; i <= 9; i++) {
                     map.put(i + "", i);
                 }
                 for (int j = 10; j < HighLetter.length + 10; j++) {
                     map.put(HighLetter[j - 10], j);
                 }
                 String[] str = new String[content.length()];
                 for (int i = 0; i < str.length; i++) {
                     str[i] = content.substring(i, i + 1);
                 }
                 for (int i = 0; i < str.length; i++) {
                     number += map.get(str[i]) * Math.pow(16, str.length - 1 - i);
                 }
                 return number;
             }
         
             /**
              * 十进制转换为ASCII码
              *
              * @param ascii
              * @return
              */
             public static String dec2Str(String ascii) {
                 StringBuilder sb = new StringBuilder();
                 for (int i = 0; i < ascii.length() - 1; i += 2) {
                     String h = ascii.substring(i, (i + 2));
                     // 这里第二个参数传10表10进制
                     int decimal = Integer.parseInt(h, 10);
                     sb.append((char) decimal);
                 }
                 return sb.toString();
             }