Springboot+Netty+Websocket实现消息推送实例
前言
WebSocket 使得客户端和服务器之间的数据交换变得更加简单,允许服务端主动向客户端推送数据。在 WebSocket API 中,浏览器和服务器只需要完成一次握手,两者之间就直接可以创建持久性的连接,并进行双向数据传输。
Netty框架的优势
1. API使用简单,开发门槛低;
2. 功能强大,预置了多种编解码功能,支持多种主流协议;
3. 定制能力强,可以通过ChannelHandler对通信框架进行灵活地扩展;
4. 性能高,通过与其他业界主流的NIO框架对比,Netty的综合性能最优;
5. 成熟、稳定,Netty修复了已经发现的所有JDK NIO BUG,业务开发人员不需要再为NIO的BUG而烦恼
提示:以下是本篇文章正文内容,下面案例可供参考
一、引入netty依赖
<dependency> <groupId>io.netty</groupId> <artifactId>netty-all</artifactId> <version>4.1.48.Final</version> </dependency>
二、使用步骤
1.引入基础配置类
package com.test.netty; public enum Cmd { START("000", "连接成功"), WMESSAGE("001", "消息提醒"), ; private String cmd; private String desc; Cmd(String cmd, String desc) { this.cmd = cmd; this.desc = desc; } public String getCmd() { return cmd; } public String getDesc() { return desc; } }
2.netty服务启动监听器
package com.test.netty; 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 org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Value; import org.springframework.boot.ApplicationRunner; import org.springframework.context.annotation.Bean; import org.springframework.stereotype.Component; /** * @author test * <p> * 服务启动监听器 **/ @Slf4j @Component public class NettyServer { @Value("${server.netty.port}") private int port; @Autowired private ServerChannelInitializer serverChannelInitializer; @Bean ApplicationRunner nettyRunner() { return args -> { //new 一个主线程组 EventLoopGroup bossGroup = new NioEventLoopGroup(1); //new 一个工作线程组 EventLoopGroup workGroup = new NioEventLoopGroup(); ServerBootstrap bootstrap = new ServerBootstrap() .group(bossGroup, workGroup) .channel(NioServerSocketChannel.class) .childHandler(serverChannelInitializer) //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(port).sync(); log.info("服务器启动开始监听端口: {}", port); future.channel().closeFuture().sync(); } catch (InterruptedException e) { e.printStackTrace(); } finally { //关闭主线程组 bossGroup.shutdownGracefully(); //关闭工作线程组 workGroup.shutdownGracefully(); } }; } }
3.netty服务端处理器
package com.test.netty; import com.test.common.util.JsonUtil; import io.netty.channel.Channel; 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.handler.codec.http.websocketx.WebSocketServerProtocolHandler; import lombok.Data; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import java.net.URLDecoder; import java.util.*; /** * @author test * <p> * netty服务端处理器 **/ @Slf4j @Component @ChannelHandler.Sharable public class NettyServerHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> { @Autowired private ServerChannelCache cache; private static final String dataKey = "test="; @Data public static class ChannelCache { } /** * 客户端连接会触发 */ @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { Channel channel = ctx.channel(); log.info("通道连接已打开,ID->{}......", channel.id().asLongText()); } @Override public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception { if (evt instanceof WebSocketServerProtocolHandler.HandshakeComplete) { Channel channel = ctx.channel(); WebSocketServerProtocolHandler.HandshakeComplete handshakeComplete = (WebSocketServerProtocolHandler.HandshakeComplete) evt; String requestUri = handshakeComplete.requestUri(); requestUri = URLDecoder.decode(requestUri, "UTF-8"); log.info("HANDSHAKE_COMPLETE,ID->{},URI->{}", channel.id().asLongText(), requestUri); String socketKey = requestUri.substring(requestUri.lastIndexOf(dataKey) + dataKey.length()); if (socketKey.length() > 0) { cache.add(socketKey, channel); this.send(channel, Cmd.DOWN_START, null); } else { channel.disconnect(); ctx.close(); } } super.userEventTriggered(ctx, evt); } @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { Channel channel = ctx.channel(); log.info("通道连接已断开,ID->{},用户ID->{}......", channel.id().asLongText(), cache.getCacheId(channel)); cache.remove(channel); } /** * 发生异常触发 */ @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { Channel channel = ctx.channel(); log.error("连接出现异常,ID->{},用户ID->{},异常->{}......", channel.id().asLongText(), cache.getCacheId(channel), cause.getMessage(), cause); cache.remove(channel); ctx.close(); } /** * 客户端发消息会触发 */ @Override protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception { try { // log.info("接收到客户端发送的消息:{}", msg.text()); ctx.channel().writeAndFlush(new TextWebSocketFrame(JsonUtil.toString(Collections.singletonMap("cmd", "100")))); } catch (Exception e) { log.error("消息处理异常:{}", e.getMessage(), e); } } public void send(Cmd cmd, String id, Object obj) { HashMap<String, Channel> channels = cache.get(id); if (channels == null) { return; } Map<String, Object> data = new LinkedHashMap<>(); data.put("cmd", cmd.getCmd()); data.put("data", obj); String msg = JsonUtil.toString(data); log.info("服务器下发消息: {}", msg); channels.values().forEach(channel -> { channel.writeAndFlush(new TextWebSocketFrame(msg)); }); } public void send(Channel channel, Cmd cmd, Object obj) { Map<String, Object> data = new LinkedHashMap<>(); data.put("cmd", cmd.getCmd()); data.put("data", obj); String msg = JsonUtil.toString(data); log.info("服务器下发消息: {}", msg); channel.writeAndFlush(new TextWebSocketFrame(msg)); } }
4.netty服务端缓存类
package com.test.netty; import io.netty.channel.Channel; import io.netty.util.AttributeKey; import org.springframework.stereotype.Component; import java.util.HashMap; import java.util.concurrent.ConcurrentHashMap; @Component public class ServerChannelCache { private static final ConcurrentHashMap<String, HashMap<String, Channel>> CACHE_MAP = new ConcurrentHashMap<>(); private static final AttributeKey<String> CHANNEL_ATTR_KEY = AttributeKey.valueOf("test"); public String getCacheId(Channel channel) { return channel.attr(CHANNEL_ATTR_KEY).get(); } public void add(String cacheId, Channel channel) { channel.attr(CHANNEL_ATTR_KEY).set(cacheId); HashMap<String, Channel> hashMap = CACHE_MAP.get(cacheId); if (hashMap == null) { hashMap = new HashMap<>(); } hashMap.put(channel.id().asShortText(), channel); CACHE_MAP.put(cacheId, hashMap); } public HashMap<String, Channel> get(String cacheId) { if (cacheId == null) { return null; } return CACHE_MAP.get(cacheId); } public void remove(Channel channel) { String cacheId = getCacheId(channel); if (cacheId == null) { return; } HashMap<String, Channel> hashMap = CACHE_MAP.get(cacheId); if (hashMap == null) { hashMap = new HashMap<>(); } hashMap.remove(channel.id().asShortText()); CACHE_MAP.put(cacheId, hashMap); } }
5.netty服务初始化器
package com.test.netty; 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.stream.ChunkedWriteHandler; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; /** * @author test * <p> * netty服务初始化器 **/ @Component public class ServerChannelInitializer extends ChannelInitializer<SocketChannel> { @Autowired private NettyServerHandler nettyServerHandler; @Override protected void initChannel(SocketChannel socketChannel) throws Exception { ChannelPipeline pipeline = socketChannel.pipeline(); pipeline.addLast(new HttpServerCodec()); pipeline.addLast(new ChunkedWriteHandler()); pipeline.addLast(new HttpObjectAggregator(8192)); pipeline.addLast(new WebSocketServerProtocolHandler("/test.io", true, 5000)); pipeline.addLast(nettyServerHandler); } }
6.html测试
<!DOCTYPE HTML> <html> <head> <meta charset="utf-8"> <title>test</title> <script type="text/javascript"> function WebSocketTest() { if ("WebSocket" in window) { alert("您的浏览器支持 WebSocket!"); // 打开一个 web socket var ws = new WebSocket("ws://localhost:port/test.io"); ws.onopen = function() { // Web Socket 已连接上,使用 send() 方法发送数据 ws.send("发送数据"); alert("数据发送中..."); }; ws.onmessage = function (evt) { var received_msg = evt.data; alert("数据已接收..."); }; ws.onclose = function() { // 关闭 websocket alert("连接已关闭..."); }; } else { // 浏览器不支持 WebSocket alert("您的浏览器不支持 WebSocket!"); } } </script> </head> <body> <div id="sse"> <a href="javascript:WebSocketTest()" rel="external nofollow" >运行 WebSocket</a> </div> </body> </html>
7.vue测试
mounted() { this.initWebsocket(); }, methods: { initWebsocket() { let websocket = new WebSocket('ws://localhost:port/test.io?test=123456'); websocket.onmessage = (event) => { let msg = JSON.parse(event.data); switch (msg.cmd) { case "000": this.$message({ type: 'success', message: "建立实时连接成功!", duration: 1000 }) setInterval(()=>{websocket.send("heartbeat")},60*1000); break; case "001": this.$message.warning("收到一条新的信息,请及时查看!") break; } } websocket.onclose = () => { setTimeout(()=>{ this.initWebsocket(); },30*1000); } websocket.onerror = () => { setTimeout(()=>{ this.initWebsocket(); },30*1000); } }, }, ![在这里插入图片描述](https://img-blog.csdnimg.cn/20210107160420568.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d1X3Fpbmdfc29uZw==,size_16,color_FFFFFF,t_70#pic_center)
8.服务器下发消息
@Autowired private NettyServerHandler nettyServerHandler; nettyServerHandler.send(CmdWeb.WMESSAGE, id, message);
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