Netty--TCP--实例

绝地灬酷狼 2023-01-14 05:00 227阅读 0赞

原文网址：[Netty--TCP--实例\_IT利刃出鞘的博客-CSDN博客\_netty tcp][Netty--TCP--_IT_-CSDN_netty tcp]

# 其他网址 #

[Netty实现简单的Socket通讯\_Touch-CSDN博客\_netty socket通信][Netty_Socket_Touch-CSDN_netty socket]  
[JAVA 网络编程(6) Netty TCP 示例\_kkgbn的博客-CSDN博客\_java netty tcp][JAVA _6_ Netty TCP _kkgbn_-CSDN_java netty tcp]  
[Netty简单示例----客户端与服务器通信\_wangshuang1631的博客-CSDN博客\_netty客户端和服务器端功能][Netty_----_wangshuang1631_-CSDN_netty]  
[Netty 实现TCP群聊系统\_mister\_Wei的博客-CSDN博客][Netty _TCP_mister_Wei_-CSDN]

# 简介 #

此方案可以用于公网与局域网的数据交互。

# 依赖及配置 #

**主要依赖**

>     <dependency>
>         <groupId>io.netty</groupId>
>         <artifactId>netty-all</artifactId>
>         <version>4.1.36.Final</version>
>     </dependency>

**pom.xml**

>     <?xml version="1.0" encoding="UTF-8"?>
>     <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>              xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
>         <modelVersion>4.0.0</modelVersion>
>         <parent>
>             <groupId>org.springframework.boot</groupId>
>             <artifactId>spring-boot-starter-parent</artifactId>
>             <version>2.4.4</version>
>             <relativePath/> 
>         </parent>
>         <groupId>com.example</groupId>
>         <artifactId>demo</artifactId>
>         <version>0.0.1-SNAPSHOT</version>
>         <name>demo</name>
>         <description>Demo project for Spring Boot</description>
>         <properties>
>             <java.version>1.8</java.version>
>         </properties>
>         <dependencies>
>             <dependency>
>                 <groupId>org.springframework.boot</groupId>
>                 <artifactId>spring-boot-starter-web</artifactId>
>             </dependency>
>     
>             <dependency>
>                 <groupId>org.springframework.boot</groupId>
>                 <artifactId>spring-boot-starter-test</artifactId>
>                 <scope>test</scope>
>             </dependency>
>     
>             <dependency>
>                 <groupId>io.netty</groupId>
>                 <artifactId>netty-all</artifactId>
>                 <version>4.1.36.Final</version>
>             </dependency>
>     
>             <dependency>
>                 <groupId>com.alibaba</groupId>
>                 <artifactId>fastjson</artifactId>
>                 <version>1.2.76</version>
>             </dependency>
>     
>             <dependency>
>                 <groupId>org.projectlombok</groupId>
>                 <artifactId>lombok</artifactId>
>                 <version>1.18.20</version>
>                 <scope>provided</scope>
>             </dependency>
>     
>         </dependencies>
>     
>         <build>
>             <plugins>
>                 <plugin>
>                     <groupId>org.springframework.boot</groupId>
>                     <artifactId>spring-boot-maven-plugin</artifactId>
>                 </plugin>
>             </plugins>
>         </build>
>     
>     </project>

**application.yml**

>     server:
>       port: 8081

# 服务端 #

## **监听端口、发数据的类** ##

package com.example.demo.tcp.server;
    
    import io.netty.bootstrap.ServerBootstrap;
    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    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.LengthFieldBasedFrameDecoder;
    import io.netty.handler.codec.LengthFieldPrepender;
    import io.netty.handler.codec.string.StringDecoder;
    import io.netty.handler.codec.string.StringEncoder;
    import io.netty.util.CharsetUtil;
    import lombok.extern.slf4j.Slf4j;
    
    @Slf4j
    public class TCPServer {
        public static void bind(int port) {
            Thread thread = new Thread(new Runnable() {
                @Override
                public void run() {
                    //服务端要建立两个group，一个负责接收客户端的连接，一个负责处理数据传输
                    //连接处理group
                    EventLoopGroup boss = new NioEventLoopGroup();
                    //事件处理group
                    EventLoopGroup worker = new NioEventLoopGroup();
                    ServerBootstrap bootstrap = new ServerBootstrap();
                    // 绑定处理group
                    bootstrap.group(boss, worker).channel(NioServerSocketChannel.class)
                            //保持连接的数目
                            .option(ChannelOption.SO_BACKLOG, 1024)
                            //有数据立即发送
                            .option(ChannelOption.TCP_NODELAY, true)
                            //保持连接
                            .childOption(ChannelOption.SO_KEEPALIVE, true)
                            //处理新连接
                            .childHandler(new ChannelInitializer<SocketChannel>() {
                                @Override
                                protected void initChannel(SocketChannel sc) throws Exception {
                                    // 增加任务处理
                                    ChannelPipeline p = sc.pipeline();
                                    p.addLast(
                                            new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4),
                                            new LengthFieldPrepender(4),
                                            new StringDecoder(CharsetUtil.UTF_8),
                                            new StringEncoder(CharsetUtil.UTF_8),
                                            //心跳检测，读超时，写超时，读写超时
                                            //new IdleStateHandler(5, 0, 0, TimeUnit.SECONDS),
                                            //自定义的处理器
                                            new TCPServerHandler()
                                    );
                                }
                            });
    
                    //绑定端口，同步等待成功
                    ChannelFuture future;
                    try {
                        future = bootstrap.bind(port).sync();
                        if (future.isSuccess()) {
                            log.info("协议==> TCP服务端启动成功(端口：{})", port);
                        } else {
                            log.info("协议==> TCP服务端启动失败(端口：{})", port);
                        }
    
                        //等待服务监听端口关闭,就是由于这里会将线程阻塞，导致无法发送信息，所以我这里开了线程
                        future.channel().closeFuture().sync();
                    } catch (Exception e) {
                        e.printStackTrace();
                    } finally {
                        //优雅地退出，释放线程池资源
                        boss.shutdownGracefully();
                        worker.shutdownGracefully();
                    }
                }
            });
            thread.start();
        }
    
        public static void sendMsg(ChannelHandlerContext ctx, String message) {
            ByteBuf byteBuf = Unpooled.copiedBuffer(message, CharsetUtil.UTF_8);
    
            ChannelFuture future = ctx.writeAndFlush(byteBuf);
            future.addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    if (future.isSuccess()) {
                        log.info("协议==> TCP服务端发送成功。");
                    } else {
                        log.error("协议==> TCP服务端发送失败。内容：{}", message);
                    }
                }
            });
        }
    
        // public static void main(String[] args) {
        //     Server server = new Server(61000);
        // }
    }

## Handler ##

package com.example.demo.tcp.server;
    
    import com.example.demo.common.cache.TCPCache;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;
    import lombok.extern.slf4j.Slf4j;
    
    import java.net.InetSocketAddress;
    import java.util.Map;
    
    @Slf4j
    public class TCPServerHandler extends ChannelInboundHandlerAdapter {
    
        // 客户端与服务端创建连接的时候调用
        @Override
        public void channelActive(ChannelHandlerContext context) throws Exception {
            log.info("协议==> TCP：客户端({})与服务端（本机）({})连接成功",
                    context.channel().remoteAddress(), context.channel().localAddress());
        }
    
        // 客户端与服务端断开连接时调用
        @Override
        public void channelInactive(ChannelHandlerContext context) throws Exception {
            log.info("协议==> TCP：客户端({})与服务端（本机）({})连接关闭",
                    context.channel().remoteAddress(), context.channel().localAddress());
            for (Map.Entry<String, ChannelHandlerContext> entry
                    : TCPCache.INSTANCE.getClientInfoContext().entrySet()) {
                if (context.equals(entry.getValue())) {
                    TCPCache.INSTANCE.getClientInfoContext().remove(entry.getKey());
                }
            }
        }
    
        // 服务端接收客户端发送过来的数据结束之后调用
        @Override
        public void channelReadComplete(ChannelHandlerContext context) throws Exception {
            context.flush();
            // System.out.println("信息接收完毕...");
        }
    
        // 工程出现异常的时候调用
        @Override
        public void exceptionCaught(ChannelHandlerContext context, Throwable cause) throws Exception {
            cause.printStackTrace();
            context.close();
        }
    
        // 服务端处理客户端websocket请求的核心方法，这里接收了客户端发来的信息
        @Override
        public void channelRead(ChannelHandlerContext context, Object info) throws Exception {
            InetSocketAddress socket = (InetSocketAddress) context.channel().remoteAddress();
            String clientIP = socket.getAddress().getHostAddress();
            String clientPort = String.valueOf(socket.getPort());
            log.info("TCP服务端（本机）收到客户端（{}:{}）的数据：{}", clientIP, clientPort, info);
    
            String key = (String) info;
            TCPCache.INSTANCE.getClientInfoContext().computeIfAbsent(key, k -> context);
        }
    }

## 配置类 ##

package com.example.demo.config;
    
    import com.example.demo.tcp.server.TCPServer;
    import org.springframework.boot.ApplicationArguments;
    import org.springframework.boot.ApplicationRunner;
    import org.springframework.stereotype.Component;
    
    @Component
    public class TCPConfig implements ApplicationRunner {
        @Override
        public void run(ApplicationArguments args) throws Exception {
            TCPServer.bind(11000);
            // TCPClient.connectToServer("127.0.0.1", 11000);
        }
    }

# 客户端 #

## 建立连接、发数据的类 ##

package com.example.demo.tcp.client;
    
    import com.example.demo.common.cache.TCPCache;
    import io.netty.bootstrap.Bootstrap;
    import io.netty.channel.*;
    import io.netty.channel.nio.NioEventLoopGroup;
    import io.netty.channel.socket.nio.NioSocketChannel;
    import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
    import io.netty.handler.codec.LengthFieldPrepender;
    import io.netty.handler.codec.string.StringDecoder;
    import io.netty.handler.codec.string.StringEncoder;
    import io.netty.util.CharsetUtil;
    import lombok.extern.slf4j.Slf4j;
    
    @Slf4j
    public class TCPClient {
        public static Bootstrap bootstrap = getBootstrap();
    
        // 初始化Bootstrap
        public static Bootstrap getBootstrap() {
            EventLoopGroup group = new NioEventLoopGroup();
            Bootstrap b = new Bootstrap();
            b.group(group).channel(NioSocketChannel.class);
            b.handler(new ChannelInitializer<Channel>() {
                @Override
                protected void initChannel(Channel ch) throws Exception {
                    ChannelPipeline pipeline = ch.pipeline();
                    pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
                    pipeline.addLast("frameEncoder", new LengthFieldPrepender(4));
                    pipeline.addLast("decoder", new StringDecoder(CharsetUtil.UTF_8));
                    pipeline.addLast("encoder", new StringEncoder(CharsetUtil.UTF_8));
                    pipeline.addLast("handler", new TCPClientHandler());
                }
            });
            b.option(ChannelOption.SO_KEEPALIVE, true);
            return b;
        }
    
        public static Channel connectToServer(String host, int port) {
            Channel channel = null;
            try {
                channel = bootstrap.connect(host, port).sync().channel();
            } catch (Exception e) {
                log.error("协议==> TCP客户端连接服务({}:{})失败", host, port, e);
                return null;
            }
    
            TCPCache.INSTANCE.getServerInfoContext().put(host + ":" + port, channel);
            return channel;
        }
    
        public static void sendMsg(String host, int port, Object data) throws Exception {
            Channel channel = TCPCache.INSTANCE.getServerInfoContext().get(host + ":" + port);
            if (channel != null) {
                channel.writeAndFlush(data).sync();
            } else {
                log.warn("协议==> TCP客户端消息发送失败，因为连接尚未建立!");
            }
        }
    }

## Handler ##

package com.example.demo.tcp.client;
    
    import io.netty.buffer.ByteBuf;
    import io.netty.buffer.Unpooled;
    import io.netty.channel.ChannelHandlerContext;
    import io.netty.channel.ChannelInboundHandlerAdapter;
    import lombok.extern.slf4j.Slf4j;
    
    import java.net.InetSocketAddress;
    import java.nio.charset.StandardCharsets;
    
    @Slf4j
    public class TCPClientHandler extends ChannelInboundHandlerAdapter {
        private static String clientName = "客户端1";
    
        @Override
        public void channelActive(ChannelHandlerContext context) throws Exception {
            log.info("协议==> TCP：客户端（本机）({})与服务器({})连接成功",
                    context.channel().localAddress(), context.channel().remoteAddress());
            ByteBuf buf = Unpooled.copiedBuffer(clientName, StandardCharsets.UTF_8);
            context.writeAndFlush(buf);
        }
    
        @Override
        public void channelRead(ChannelHandlerContext context, Object msg) throws Exception {
            InetSocketAddress socket = (InetSocketAddress) context.channel().remoteAddress();
            String clientIP = socket.getAddress().getHostAddress();
            String clientPort = String.valueOf(socket.getPort());
            log.info("TCP客户端（本机）收到服务端（{}:{}）的数据：{}", clientIP, clientPort, msg);
        }
    }

## 配置类 ##

package com.example.demo.config;
    
    import com.example.demo.tcp.client.TCPClient;
    import org.springframework.boot.ApplicationArguments;
    import org.springframework.boot.ApplicationRunner;
    import org.springframework.stereotype.Component;
    
    @Component
    public class TCPConfig implements ApplicationRunner {
        @Override
        public void run(ApplicationArguments args) throws Exception {
            // TCPServer.bind(11000);
            TCPClient.connectToServer("127.0.0.1", 11000);
        }
    }

# 公共代码 #

保存客户端/服务端 与 TCP连接的对应关系

package com.example.demo.common.cache;
    
    import io.netty.channel.Channel;
    import io.netty.channel.ChannelHandlerContext;
    
    import java.util.Map;
    import java.util.concurrent.ConcurrentHashMap;
    
    public enum TCPCache {
        INSTANCE;
    
        private Map<String, ChannelHandlerContext> clientInfoContext = new ConcurrentHashMap<>();
        private Map<String, Channel> serverInfoContext = new ConcurrentHashMap<>();
    
        public Map<String, ChannelHandlerContext> getClientInfoContext() {
            return clientInfoContext;
        }
    
        public Map<String, Channel> getServerInfoContext() {
            return serverInfoContext;
        }
    }

# 测试代码 #

**客户端Controller**

>     package com.example.demo.controller;
>     
>     import com.example.demo.tcp.client.TCPClient;
>     import org.springframework.web.bind.annotation.PostMapping;
>     import org.springframework.web.bind.annotation.RequestMapping;
>     import org.springframework.web.bind.annotation.RestController;
>     
>     @RestController
>     @RequestMapping("client")
>     public class TCPClientController {
>     
>         @PostMapping("send")
>         public String send(String host, Integer port, String msg) {
>             try {
>                 TCPClient.sendMsg(host, port, msg);
>             } catch (Exception e) {
>                 e.printStackTrace();
>             }
>             return "success";
>         }
>     }

**服务端Controller**

>     package com.example.demo.controller;
>     
>     import com.example.demo.common.cache.TCPCache;
>     import io.netty.channel.ChannelHandlerContext;
>     import org.springframework.web.bind.annotation.PostMapping;
>     import org.springframework.web.bind.annotation.RequestMapping;
>     import org.springframework.web.bind.annotation.RestController;
>     
>     @RestController
>     @RequestMapping("server")
>     public class TCPServerController {
>         @PostMapping("send")
>         public String send(String clientName, String msg) {
>             ChannelHandlerContext context = TCPCache.INSTANCE.getClientInfoContext().get(clientName);
>             context.writeAndFlush(msg);
>             return "success";
>         }
>     }

# 测试 #

**启动**

> 以8080端口，启动服务器；以8081端口，启动客户端

> **服务端打印**
> 
>     2021-04-20 09:56:08.243  INFO 78272 --- [       Thread-5] com.example.demo.tcp.server.TCPServer    : 协议==> TCP服务端启动成功(端口：11000)
>     2021-04-20 09:56:23.311  INFO 78272 --- [ntLoopGroup-3-1] c.e.demo.tcp.server.TCPServerHandler     : 协议==> TCP：客户端(/127.0.0.1:51396)与服务端（本机）(/127.0.0.1:11000)连接成功
>     2021-04-20 09:56:23.331  INFO 78272 --- [ntLoopGroup-3-1] c.e.demo.tcp.server.TCPServerHandler     : TCP服务端（本机）收到客户端（127.0.0.1:51396）的数据：客户端1
> 
> **客户端打印**
> 
>     2021-04-20 09:56:23.298  INFO 79792 --- [ntLoopGroup-2-1] c.e.demo.tcp.client.TCPClientHandler     : 协议==> TCP：客户端（本机）(/127.0.0.1:51396)与服务器(/127.0.0.1:11000)连接成功

**测试**

> 请求客户端接口：http://localhost:8081/client/send?host=127.0.0.1&port=11000&msg=Message from 客户端1
> 
> 服务端打印
> 
>     2021-04-20 09:56:33.283  INFO 78272 --- [ntLoopGroup-3-1] c.e.demo.tcp.server.TCPServerHandler     : TCP服务端（本机）收到客户端（127.0.0.1:51396）的数据：Message from 客户端1

> 请求服务端接口：http://localhost:8080/server/send?clientName=客户端1&msg=Message from 服务器
> 
> 客户端打印
> 
>     2021-04-20 09:56:50.765  INFO 79792 --- [ntLoopGroup-2-1] c.e.demo.tcp.client.TCPClientHandler     : TCP客户端（本机）收到服务端（127.0.0.1:11000）的数据：Message from 服务器

[Netty--TCP--_IT_-CSDN_netty tcp]: https://knife.blog.csdn.net/article/details/115894183
[Netty_Socket_Touch-CSDN_netty socket]: https://blog.csdn.net/BThinker/article/details/103662689
[JAVA _6_ Netty TCP _kkgbn_-CSDN_java netty tcp]: https://blog.csdn.net/kkgbn/article/details/52252319
[Netty_----_wangshuang1631_-CSDN_netty]: https://blog.csdn.net/wangshuang1631/article/details/72911464
[Netty _TCP_mister_Wei_-CSDN]: https://blog.csdn.net/mister_Wei/article/details/103815361