[经验] Java 使用 netty 框架, 向 Unity 客户端的 C# 实现通信 [1]

这是一个较为立体的思路吧

首先是技术选型:

前端 : HTML5 + jQuery ,简单暴力, 不解释

服务端 : Spring Boot + Netty + Redis/Cache

客户端 : Unity3D + C#

所要实现的效果为:

服务端启动后, 开启端口监听, 然后客户端启动, 连接上服务端, 再由前端将数据请求发送到服务端, 服务端再发送到客户端

为了方便(懒), 所以使用 netty 4.x 作为主要的通讯框架, 由于 5.X好像已经被官方放弃了, 所以我就使用最新版的

在 pom.xml 处添加 netty4.x 的依赖

        <!-- netty 通信框架 https://mvnrepository.com/artifact/io.netty/netty-all -->
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.0.39.Final</version>
        </dependency>

        <!-- netty websocket 通讯框架依赖 -->
        <dependency>
            <groupId>org.yeauty</groupId>
            <artifactId>netty-websocket-spring-boot-starter</artifactId>
            <version>0.8.0</version>
        </dependency

老规矩, 从服务端开始, 先创建 netty 的服务端程序

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.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.stream.ChunkedWriteHandler;
import io.netty.handler.timeout.IdleStateHandler;
import org.apache.http.client.utils.DateUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

/*
 *@Description //TODO NIO 服务端$
 *@Author 吾王剑锋所指 吾等心之所向
 *@Date 2019/8/27 19:18
 */
public class NettyServer {
    private static final Logger logger = LoggerFactory.getLogger(NettyServer.class);//默认端口
    private Integer defaultPort = 5566;
    public void bind(Integer port) throws Exception {
        //配置服务端的NIO线程组
        EventLoopGroup master = new NioEventLoopGroup();
        EventLoopGroup servant = new NioEventLoopGroup();
        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(master, servant).channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            //将响应请求消息解码为 HTTP 消息
                            socketChannel.pipeline().addLast("http-codec", new HttpServerCodec());
                            //将HTTP消息的多个部分构建成一条完整的 HTTP 消息
                            socketChannel.pipeline().addLast("aggregator",new HttpObjectAggregator(2048));
                            //向客户端发送 HTML5 文件
                            socketChannel.pipeline().addLast("http-chunked", new ChunkedWriteHandler());
                            //设置心跳检测
                            socketChannel.pipeline().addLast(new IdleStateHandler(60, 30, 60*30, TimeUnit.SECONDS));
                            //配置通道, 进行业务处理
                            socketChannel.pipeline().addLast(new NettyServerHandler());
                        }
                    })
                    .option(ChannelOption.SO_BACKLOG, 1024)
                    .option(ChannelOption.SO_KEEPALIVE, true) // 2小时无数据激活心跳机制
                    .childHandler(new ServerChannelInitializer());


            if(null==port) port=this.defaultPort; // 服务器异步创建绑定

            ChannelFuture future = bootstrap.bind(port).sync();
            logger.info("服务启动："+ DateUtils.formatDate(new Date()));
            future.channel().closeFuture().sync();  // 关闭服务器通道
        } finally {
            logger.info("服务停止："+ DateUtils.formatDate(new Date()));
            // 释放线程池资源
            master.shutdownGracefully();
            servant.shutdownGracefully();
        }
    }
}

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

/*
 *@Description //TODO nio 服务端实现$
 *@Author 吾王剑锋所指 吾等心之所向
 *@Date 2019/8/27 19:20
 */
public class ServerChannelInitializer extends ChannelInitializer<SocketChannel> {
    @Override
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        ChannelPipeline pipeline = socketChannel.pipeline();
        pipeline.addLast(new LineBasedFrameDecoder(10010));
        pipeline.addLast( new StringDecoder());
        pipeline.addLast( new StringEncoder());
        pipeline.addLast("handler", new NettyServerHandler());
    }
}

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.codec.http.*;
import io.netty.handler.codec.http.websocketx.*;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.util.AttributeKey;
import io.netty.util.CharsetUtil;

import org.apache.http.client.utils.DateUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Date;

/*
 *@Description //TODO 服务业务实现$
 *@Author 吾王剑锋所指 吾等心之所向三
 *@Date 2019/8/28 9:50
 */
public class NettyServerHandler extends SimpleChannelInboundHandler<Object> {
    private static Logger LOGGER = LoggerFactory.getLogger(NettyServerHandler.class);

    private static final String URI = "websocket";
    private WebSocketServerHandshaker handshaker;

    /**
     * 读取客户端发来的数据
     *
     */
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        String[] data = msg.toString().split("id=");
        if(data != null && data.length > 1) {
            String[] data1 = data[1].split(";");
            String id = data1[0];
            if (NettyServer.map.get(id) != null && NettyServer.map.get(id).equals(ctx)) { //不是第一次连接
                LOGGER.info("接收数据成功！" + DateUtils.formatDate(new Date()));
            } else { //如果map中没有此ctx 将连接存入map中
                NettyServer.map.put(id, ctx);
                LOGGER.info("连接成功，加入map管理连接！"+"mn:" +id+" : "+ctx+""+ DateUtils.formatDate(new Date()));
            }
        }else{
            LOGGER.info("不是监测数据"+ msg.toString()+" : "+ DateUtils.formatDate(new Date()));
        }
        ctx.writeAndFlush("Received your message : " + msg.toString());
    }


    /**
     *  读取完毕客户端发送过来的数据之后的操作
     * */
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        LOGGER.info("服务端接收数据完毕..");
        ctx.channel().write("call ------"); //向客户端发送一条信息
        ctx.channel().flush();
    }

    /**
     * 客户端主动断开服务端的链接,关闭流
     * */
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(ctx.channel().localAddress().toString() + " 通道不活跃！");
        removeChannelMap(ctx);
        ctx.close(); // 关闭流
    }

    /**
     * 客户端主动连接服务端 连接成功时向客户端发送一条信息
     *
     * */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        LOGGER.info("RemoteAddress"+ ctx.channel().remoteAddress() + " active !");
        LOGGER.info("msg send active !"+ctx.channel().writeAndFlush("123456"));
        ctx.writeAndFlush("啦啦啦！");super.channelActive(ctx);
    }

    /**
     * 异常处理
     *
     * */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        LOGGER.error("连接异常,连接异常："+ DateUtils.formatDate(new Date())+cause.getMessage(), cause);
        ctx.fireExceptionCaught(cause);
        removeChannelMap(ctx);
        ctx.close();
    }

    /**
     *删除map中ChannelHandlerContext
     *
     *  */
    private void removeChannelMap(ChannelHandlerContext ctx){
        for( String key :NettyServer.map.keySet()){
            if( NettyServer.map.get(key)!=null &&  NettyServer.map.get(key).equals( ctx)){
                NettyServer.map.remove(key);
            }
        }
    }

    /**
     * 收发消息处理
     *
     * */
    protected void messageReceived(ChannelHandlerContext ctx, Object msg) throws Exception{
        if(msg instanceof HttpRequest){
            doHandlerHttpRequest(ctx, (HttpRequest) msg);
        }else if(msg instanceof HttpRequest){
            doHandlerWebSocketFrame(ctx, (WebSocketFrame) msg);
        }
    }

    /**
     * 进行心跳检测, 保证用户在线
     *
     *
     * */
    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
        if(evt instanceof IdleStateEvent){
            IdleStateEvent stateEvent = (IdleStateEvent) evt;
            PingWebSocketFrame ping = new PingWebSocketFrame();
            switch (stateEvent.state()){
                case READER_IDLE: //读空闲 服务器端
                    LOGGER.info("{["+ctx.channel().remoteAddress()+"]--->(服务端 read 空闲)}");
                    ctx.writeAndFlush(ping);
                    break;
                case WRITER_IDLE: //写空闲 服务器端
                    LOGGER.info("{["+ctx.channel().remoteAddress()+"]--->(服务端 write 空闲)}");
                    ctx.writeAndFlush(ping);
                    break;
                case ALL_IDLE: //读写空闲 服务器端
                    LOGGER.info("{["+ctx.channel().remoteAddress()+"]--->(服务端 读写 空闲)}");
            }
        }
    }

    /**
     *  websocket 消息处理
     *
     * */
    protected void doHandlerWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame msg){
        if(msg instanceof CloseWebSocketFrame){ //判断 msg 是哪一种类型, 分别作出不同的反应
            LOGGER.info("[{---关闭---}]");
            handshaker.close(ctx.channel(), (CloseWebSocketFrame) msg);
            return;
        }

        if(msg instanceof PingWebSocketFrame){
            LOGGER.info("[{---ping}]");
            PongWebSocketFrame pong = new PongWebSocketFrame(msg.content().retain());
            ctx.channel().writeAndFlush(pong);
            return;
        }

        if(!(msg instanceof TextWebSocketFrame)){
            LOGGER.info("[{!!----不支持二进制-----!!}]");
        }
    }

    /**
     * websocket 第一次握手
     *
     * */
    public void doHandlerHttpRequest(ChannelHandlerContext ctx, HttpRequest msg){
        //http 解码失败
        if(!msg.getDecoderResult().isSuccess() || (!"websocket".equals(msg.headers().get("Upgrade")))){
            sendHttpResponse(ctx, (FullHttpRequest) msg,
                    new DefaultFullHttpResponse(HttpVersion.HTTP_1_1,
                            HttpResponseStatus.BAD_REQUEST));
        }

        //可以获取 msg 的URI来判断
        String uri = msg.getUri();
        if(!uri.substring(1).equals(URI)){
            ctx.close();
        }
        ctx.attr(AttributeKey.valueOf("type")).set(uri);

        //通过 URI 获取其他参数验证
        WebSocketServerHandshakerFactory factory =
                new WebSocketServerHandshakerFactory(
                        "ws://"+msg.headers().get("Host")+"/"+URI+"",
                        null,
                        false);
        handshaker = factory.newHandshaker(msg);
        if(handshaker == null){
            WebSocketServerHandshakerFactory.sendUnsupportedWebSocketVersionResponse(ctx.channel());
        }

        //进行连接
        handshaker.handshake(ctx.channel(), (FullHttpRequest) msg);

    }

    /**
     * 返回应答给客户端
     *
     * */
    private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, DefaultFullHttpResponse res){
        if(res.getStatus().code() != 200){
            ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8);
            res.content().writeBytes(buf);
            buf.release();
        }

        // 如果是非 keep-alive , 关闭连接
        ChannelFuture cf = ctx.channel().writeAndFlush(res);
        if (!HttpHeaders.isKeepAlive(req) || res.getStatus().code() != 200) {
            cf.addListener(ChannelFutureListener.CLOSE);
        }
    }

    /**
     * 断开连接
     *
     * */
    @Override
    public void handlerRemoved(ChannelHandlerContext ctx) throws Exception{
        LOGGER.info("handlerRemoved ---->"+ctx.channel());
    }

}

然后再在系统启动文件的地方开启启动netty 服务的线程就可以

import cn.gzserver.basics.network.netty.NettyServer;
import cn.gzserver.basics.network.socket.SocketServer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.scheduling.annotation.EnableScheduling;

/*@ComponentScan*/
@EnableScheduling
@SpringBootApplication
@EnableDiscoveryClient
public class GzserverApplication {

    public static void main(String[] args) {
        SpringApplication.run(GzserverApplication.class, args);

        //启动 socket 服务, 接收客户端发送连接请求, 并返回数据
        /*SocketServer socketServer = new SocketServer();
        socketServer.start();*/

        //开启 netty 服务
        new Thread(() -> {
            try {
                new NettyServer().bind(5566);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }).start();
    }


}

然后呢, 客户端的配置基本上没有改变, 可以参考我前面写的一篇博客作为参考就行

https://www.cnblogs.com/unityworld/p/11345431.html

但是,还有一些问题, 会在下一篇文章中说明

[经验] Java 使用 netty 框架, 向 Unity 客户端的 C# 实现通信 [1]

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