Springboot + netty +websocket 实现推送消息
学过 Netty 的都知道，Netty 对 NIO 进行了很好的封装，简单的 API，庞大的开源社区。深受广大程序员喜爱。基于此本文分享一下基础的 netty 使用。
maven集成
<!-- https://mvnrepository.com/artifact/io.netty/netty-all --> <dependency> <groupId>io.netty</groupId> <artifactId>netty-all</artifactId> <version>4.1.87.Final</version> </dependency>
netty服务器
package com.hikvision.websocketparent.dl05; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.ChannelFuture; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.nio.NioServerSocketChannel; 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 javax.annotation.PostConstruct; import javax.annotation.PreDestroy; import java.net.InetSocketAddress; /** * @author dongliang7 * @projectName websocket-parent * @ClassName NettyServer.java * @description: TODO * @createTime 2023年02月06日 16:41:00 */ @Component public class NettyServer { static final Logger log = LoggerFactory.getLogger(NettyServer.class); /** * 端口号 */ @Value("${webSocket.netty.port:8889}") int port; EventLoopGroup bossGroup; EventLoopGroup workGroup; @Autowired ProjectInitializer nettyInitializer; @PostConstruct public void start() throws InterruptedException { new Thread(() -> { bossGroup = new NioEventLoopGroup(); workGroup = new NioEventLoopGroup(); ServerBootstrap bootstrap = new ServerBootstrap(); // bossGroup辅助客户端的tcp连接请求, workGroup负责与客户端之前的读写操作 bootstrap.group(bossGroup, workGroup); // 设置NIO类型的channel bootstrap.channel(NioServerSocketChannel.class); // 设置监听端口 bootstrap.localAddress(new InetSocketAddress(port)); // 设置管道 bootstrap.childHandler(nettyInitializer); // 配置完成，开始绑定server，通过调用sync同步方法阻塞直到绑定成功 ChannelFuture channelFuture = null; try { channelFuture = bootstrap.bind().sync(); log.info("Server started and listen on:{}", channelFuture.channel().localAddress()); // 对关闭通道进行监听 channelFuture.channel().closeFuture().sync(); } catch (InterruptedException e) { e.printStackTrace(); } }).start(); } /** * 释放资源 */ @PreDestroy public void destroy() throws InterruptedException { if (bossGroup != null) { bossGroup.shutdownGracefully().sync(); } if (workGroup != null) { workGroup.shutdownGracefully().sync(); } } }
Netty配置
管理全局Channel以及用户对应的channel（推送消息）
package com.hikvision.websocketparent.dl05; import io.netty.channel.Channel; import io.netty.channel.group.ChannelGroup; import io.netty.channel.group.DefaultChannelGroup; import io.netty.util.concurrent.GlobalEventExecutor; import java.util.concurrent.ConcurrentHashMap; /** * @author dongliang7 * @projectName websocket-parent * @ClassName NettyConfig.java * @description: 管理全局Channel以及用户对应的channel（推送消息） * @createTime 2023年02月06日 16:43:00 */ public class NettyConfig { /** * 定义全局单利channel组 管理所有channel */ private static volatile ChannelGroup channelGroup = null; /** * 存放请求ID与channel的对应关系 */ private static volatile ConcurrentHashMap<String, Channel> channelMap = null; /** * 定义两把锁 */ private static final Object lock1 = new Object(); private static final Object lock2 = new Object(); public static ChannelGroup getChannelGroup() { if (null == channelGroup) { synchronized (lock1) { if (null == channelGroup) { channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE); } } } return channelGroup; } public static ConcurrentHashMap<String, Channel> getChannelMap() { if (null == channelMap) { synchronized (lock2) { if (null == channelMap) { channelMap = new ConcurrentHashMap<>(); } } } return channelMap; } public static Channel getChannel(String userId) { if (null == channelMap) { return getChannelMap().get(userId); } return channelMap.get(userId); } }
管道配置
package com.hikvision.websocketparent.dl05; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; import io.netty.handler.codec.http.HttpObjectAggregator; import io.netty.handler.codec.http.HttpServerCodec; import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler; import io.netty.handler.codec.serialization.ObjectEncoder; import io.netty.handler.stream.ChunkedWriteHandler; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Value; import org.springframework.stereotype.Component; /** * @author dongliang7 * @projectName websocket-parent * @ClassName ProjectInitializer.java * @description: 管道配置 * @createTime 2023年02月06日 16:43:00 */ @Component public class ProjectInitializer extends ChannelInitializer<SocketChannel> { /** * webSocket协议名 */ static final String WEBSOCKET_PROTOCOL = "WebSocket"; /** * webSocket路径 */ @Value("${webSocket.netty.path:/webSocket}") String webSocketPath; @Autowired WebSocketHandler webSocketHandler; @Override protected void initChannel(SocketChannel socketChannel) throws Exception { // 设置管道 ChannelPipeline pipeline = socketChannel.pipeline(); // 流水线管理通道中的处理程序（Handler），用来处理业务 // webSocket协议本身是基于http协议的，所以这边也要使用http编解码器 pipeline.addLast(new HttpServerCodec()); pipeline.addLast(new ObjectEncoder()); // 以块的方式来写的处理器 pipeline.addLast(new ChunkedWriteHandler()); pipeline.addLast(new HttpObjectAggregator(8192)); pipeline.addLast(new WebSocketServerProtocolHandler(webSocketPath, WEBSOCKET_PROTOCOL, true, 65536 * 10)); // 自定义的handler，处理业务逻辑 pipeline.addLast(webSocketHandler); } }
自定义handler
package com.hikvision.websocketparent.dl05; import cn.hutool.json.JSONObject; import cn.hutool.json.JSONUtil; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.websocketx.TextWebSocketFrame; import io.netty.util.AttributeKey; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.stereotype.Component; /** * @author dongliang7 * @projectName websocket-parent * @ClassName WebSocketHandler.java * @description: TODO * @createTime 2023年02月06日 16:44:00 */ @Component @ChannelHandler.Sharable public class WebSocketHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> { private static final Logger log = LoggerFactory.getLogger(NettyServer.class); /** * 一旦连接，第一个被执行 */ @Override public void handlerAdded(ChannelHandlerContext ctx) throws Exception { log.info("有新的客户端链接：[{}]", ctx.channel().id().asLongText()); // 添加到channelGroup 通道组 NettyConfig.getChannelGroup().add(ctx.channel()); } /** * 读取数据 */ @Override protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception { log.info("服务器收到消息：{}", msg.text()); // 获取用户ID,关联channel JSONObject jsonObject = JSONUtil.parseObj(msg.text()); String uid = jsonObject.getStr("uid"); NettyConfig.getChannelMap().put(uid, ctx.channel()); // 将用户ID作为自定义属性加入到channel中，方便随时channel中获取用户ID AttributeKey<String> key = AttributeKey.valueOf("userId"); ctx.channel().attr(key).setIfAbsent(uid); // 回复消息 ctx.channel().writeAndFlush(new TextWebSocketFrame("服务器收到消息啦")); } @Override public void handlerRemoved(ChannelHandlerContext ctx) throws Exception { log.info("用户下线了:{}", ctx.channel().id().asLongText()); // 删除通道 NettyConfig.getChannelGroup().remove(ctx.channel()); removeUserId(ctx); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { log.info("异常：{}", cause.getMessage()); // 删除通道 NettyConfig.getChannelGroup().remove(ctx.channel()); removeUserId(ctx); ctx.close(); } /** * 删除用户与channel的对应关系 */ private void removeUserId(ChannelHandlerContext ctx) { AttributeKey<String> key = AttributeKey.valueOf("userId"); String userId = ctx.channel().attr(key).get(); NettyConfig.getChannelMap().remove(userId); } }
推送消息接口及实现类
package com.hikvision.websocketparent.dl05; /** * @author dongliang7 * @projectName websocket-parent * @ClassName PushMsgService.java * @description: 推送消息接口 * @createTime 2023年02月06日 16:44:00 */ public interface PushMsgService { /** * 推送给指定用户 */ void pushMsgToOne(String userId, String msg); /** * 推送给所有用户 */ void pushMsgToAll(String msg); }
package com.hikvision.websocketparent.dl05; import io.netty.channel.Channel; import io.netty.handler.codec.http.websocketx.TextWebSocketFrame; import org.springframework.stereotype.Service; import java.util.Objects; /** * @author dongliang7 * @projectName websocket-parent * @ClassName PushMsgServiceImpl.java * @description: 推送消息实现类 * @createTime 2023年02月06日 16:45:00 */ @Service public class PushMsgServiceImpl implements PushMsgService { @Override public void pushMsgToOne(String userId, String msg) { Channel channel = NettyConfig.getChannel(userId); if (Objects.isNull(channel)) { throw new RuntimeException("未连接socket服务器"); } channel.writeAndFlush(new TextWebSocketFrame(msg)); } @Override public void pushMsgToAll(String msg) { NettyConfig.getChannelGroup().writeAndFlush(new TextWebSocketFrame(msg)); } }
测试controller层接口
package com.hikvision.websocketparent.dl05; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; /** * @author dongliang7 * @projectName * @ClassName TestController.java * @description: TODO * @createTime 2023年02月06日 17:48:00 */ @RestController @RequestMapping("/push") public class TestController { @Autowired PushMsgService pushMsgService; /** * 推送消息到具体客户端 * @param uid */ @GetMapping("/{uid}") public void pushOne(@PathVariable String uid) { pushMsgService.pushMsgToOne(uid, "hello-------------------------"); } /** * 推送消息到所有客户端 */ @GetMapping("/pushAll") public void pushAll() { pushMsgService.pushMsgToAll("hello all-------------------------"); } }
测试
在线模拟websocket请求工具
https://www.bejson.com/httputil/websocket/
