Java Springboot websocket使用案例详解

什么是WebSocket

WebSocket是一种在单个TCP连接上进行全双工通信的协议 …

为什么要实现握手监控管理

如果说，连接随意创建，不管的话，会存在错误，broken pipe

表面看单纯报错，并没什么功能缺陷等，但实际，请求数增加，容易导致系统奔溃。这边画重点。

出现原因有很多种，目前我这边出现的原因，是因为客户端已关闭连接，服务端还持续推送导致。

如何使用

下面将使用springboot集成的webSocket

导入Maven

首先SpringBoot版本

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.8.RELEASE</version>
</parent>

集成websocket

// 加个web集成吧
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

Java代码

Config配置

首先，我们需要重写WebSocketHandlerDecoratorFactory

主要用来监控客户端握手连接进来以及挥手关闭连接

代码

需要一个管理Socket的类

package com.li.manager;

import lombok.extern.slf4j.Slf4j;
import org.springframework.web.socket.WebSocketSession;

import java.util.concurrent.ConcurrentHashMap;

/**
 * socket管理器
 */
@Slf4j
public class SocketManager {
    private static ConcurrentHashMap<String, WebSocketSession> manager = new ConcurrentHashMap<String, WebSocketSession>();

    public static void add(String key, WebSocketSession webSocketSession) {
        log.info("新添加webSocket连接 {} ", key);
        manager.put(key, webSocketSession);
    }

    public static void remove(String key) {
        log.info("移除webSocket连接 {} ", key);
        manager.remove(key);
    }

    public static WebSocketSession get(String key) {
        log.info("获取webSocket连接 {}", key);
        return manager.get(key);
    }

}

package com.li.factory;

import com.li.manager.SocketManager;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.WebSocketHandlerDecorator;
import org.springframework.web.socket.handler.WebSocketHandlerDecoratorFactory;

import java.security.Principal;

/**
 * 服务端和客户端在进行握手挥手时会被执行
 */
@Component
@Slf4j
public class WebSocketDecoratorFactory implements WebSocketHandlerDecoratorFactory {
    @Override
    public WebSocketHandler decorate(WebSocketHandler handler) {
        return new WebSocketHandlerDecorator(handler) {
            @Override
            public void afterConnectionEstablished(WebSocketSession session) throws Exception {
                log.info("有人连接啦  sessionId = {}", session.getId());
                Principal principal = session.getPrincipal();
                if (principal != null) {
                    log.info("key = {} 存入", principal.getName());
                    // 身份校验成功，缓存socket连接
                    SocketManager.add(principal.getName(), session);
                }

                super.afterConnectionEstablished(session);
            }

            @Override
            public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
                log.info("有人退出连接啦  sessionId = {}", session.getId());
                Principal principal = session.getPrincipal();
                if (principal != null) {
                    // 身份校验成功，移除socket连接
                    SocketManager.remove(principal.getName());
                }
                super.afterConnectionClosed(session, closeStatus);
            }
        };
    }
}

注意：以上session变量，需要注意两点，一个是getId(),一个是getPrincipal().getName()

getId() ： 返回的是唯一的会话标识符。

getPrincipal() : 经过身份验证，返回Principal实例，未经过身份验证，返回null

Principal: 委托人的抽象概念,可以是公司id，名字，用户唯一识别token等

当你按上面代码使用，你会发现getPrincipal()返回null，为什么？这边还需要重写一个DefaultHandshakeHandler

代码

package com.li.handler;

import lombok.extern.slf4j.Slf4j;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.support.DefaultHandshakeHandler;

import javax.servlet.http.HttpServletRequest;
import java.security.Principal;
import java.util.Map;

/**
 * 我们可以通过请求信息，比如token、或者session判用户是否可以连接，这样就能够防范非法用户
 */
@Slf4j
@Component
public class PrincipalHandshakeHandler extends DefaultHandshakeHandler {
    @Override
    protected Principal determineUser(ServerHttpRequest request, WebSocketHandler wsHandler, Map<String, Object> attributes) {
        /**
         * 这边可以按你的需求，如何获取唯一的值，既unicode
         * 得到的值，会在监听处理连接的属性中，既WebSocketSession.getPrincipal().getName()
         * 也可以自己实现Principal()
         */
        if (request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest servletServerHttpRequest = (ServletServerHttpRequest) request;
            HttpServletRequest httpRequest = servletServerHttpRequest.getServletRequest();
            /**
             * 这边就获取你最熟悉的陌生人,携带参数，你可以cookie，请求头，或者url携带，这边我采用url携带
             */
            final String token = httpRequest.getParameter("token");
            if (StringUtils.isEmpty(token)) {
                return null;
            }
            return new Principal() {
                @Override
                public String getName() {
                    return token;
                }
            };
        }
        return null;
    }
}

需要的东西都有了，那准备装载吧

代码

package com.li.config;

import com.li.factory.WebSocketDecoratorFactory;
import com.li.handler.PrincipalHandshakeHandler;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.simp.config.MessageBrokerRegistry;
import org.springframework.web.socket.config.annotation.AbstractWebSocketMessageBrokerConfigurer;
import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker;
import org.springframework.web.socket.config.annotation.StompEndpointRegistry;
import org.springframework.web.socket.config.annotation.WebSocketTransportRegistration;

/**
 * WebSocketConfig配置
 */
@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {

    @Autowired
    private WebSocketDecoratorFactory webSocketDecoratorFactory;
    @Autowired
    private PrincipalHandshakeHandler principalHandshakeHandler;

    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        /**
         * myUrl表示 你前端到时要对应url映射
         */
        registry.addEndpoint("/myUrl")
                .setAllowedOrigins("*")
                .setHandshakeHandler(principalHandshakeHandler)
                .withSockJS();
    }

    @Override
    public void configureMessageBroker(MessageBrokerRegistry registry) {
        /**
         * queue 点对点
         * topic 广播
         * user 点对点前缀
         */
        registry.enableSimpleBroker("/queue", "/topic");
        registry.setUserDestinationPrefix("/user");
    }

    @Override
    public void configureWebSocketTransport(WebSocketTransportRegistration registration) {
        registration.addDecoratorFactory(webSocketDecoratorFactory);
        super.configureWebSocketTransport(registration);
    }
}

终于完成了

最后，来一个通过http请求，将其发送到客户端

代码

package com.li.controller;

import com.li.manager.SocketManager;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.handler.annotation.MessageMapping;
import org.springframework.messaging.handler.annotation.SendTo;
import org.springframework.messaging.simp.SimpMessagingTemplate;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.socket.WebSocketSession;

import java.util.Map;

@RestController
@Slf4j
public class TestController {

    @Autowired
    private SimpMessagingTemplate template;

    /**
     * 服务器指定用户进行推送,需要前端开通 var socket = new SockJS(host+'/myUrl' + '?token=1234');
     */
    @RequestMapping("/sendUser")
    public void sendUser(String token) {
        log.info("token = {} ,对其发送您好", token);
        WebSocketSession webSocketSession = SocketManager.get(token);
        if (webSocketSession != null) {
            /**
             * 主要防止broken pipe
             */
            template.convertAndSendToUser(token, "/queue/sendUser", "您好");
        }

    }

    /**
     * 广播，服务器主动推给连接的客户端
     */
    @RequestMapping("/sendTopic")
    public void sendTopic() {
        template.convertAndSend("/topic/sendTopic", "大家晚上好");

    }

    /**
     * 客户端发消息，服务端接收
     *
     * @param message
     */
    // 相当于RequestMapping
    @MessageMapping("/sendServer")
    public void sendServer(String message) {
        log.info("message:{}", message);
    }

    /**
     * 客户端发消息，大家都接收，相当于直播说话
     *
     * @param message
     * @return
     */
    @MessageMapping("/sendAllUser")
    @SendTo("/topic/sendTopic")
    public String sendAllUser(String message) {
        // 也可以采用template方式
        return message;
    }

    /**
     * 点对点用户聊天，这边需要注意，由于前端传过来json数据，所以使用@RequestBody
     * 这边需要前端开通var socket = new SockJS(host+'/myUrl' + '?token=4567');   token为指定name
     * @param map
     */
    @MessageMapping("/sendMyUser")
    public void sendMyUser(@RequestBody Map<String, String> map) {
        log.info("map = {}", map);
        WebSocketSession webSocketSession = SocketManager.get(map.get("name"));
        if (webSocketSession != null) {
            log.info("sessionId = {}", webSocketSession.getId());
            template.convertAndSendToUser(map.get("name"), "/queue/sendUser", map.get("message"));
        }
    }

}

前端代码

可以直接启动

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>Spring Boot WebSocket+广播式</title>
</head>
<body>
    <noscript>
        <h2 style="color:#ff0000">貌似你的浏览器不支持websocket</h2>
    </noscript>
    <div>
        <div>
            <button id="connect" onclick="connect()">连接</button>
            <button id="disconnect"  onclick="disconnect();">断开连接</button>
        </div>
        <div id="conversationDiv">
            <label>输入你的名字</label> <input type="text" id="name" />
            <br>
            <label>输入消息</label> <input type="text" id="messgae" />
            <button id="send" onclick="send();">发送</button>
            <p id="response"></p>
        </div>
    </div>
    <script src="https://cdn.bootcss.com/sockjs-client/1.1.4/sockjs.min.js"></script>
    <script src="https://cdn.bootcss.com/stomp.js/2.3.3/stomp.min.js"></script>
    <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>
    <script type="text/javascript">
        var stompClient = null;
        //gateway网关的地址
        var host="http://127.0.0.1:8888";
        function setConnected(connected) {
            document.getElementById('connect').disabled = connected;
            document.getElementById('disconnect').disabled = !connected;
            document.getElementById('conversationDiv').style.visibility = connected ? 'visible' : 'hidden';
            $('#response').html();
        }
        // SendUser ***********************************************
        function connect() {
            //地址+端点路径，构建websocket链接地址,注意，对应config配置里的addEndpoint
            var socket = new SockJS(host+'/myUrl' + '?token=4567');
            stompClient = Stomp.over(socket);
            stompClient.connect({}, function(frame) {
                setConnected(true);
                console.log('Connected:' + frame);
                //监听的路径以及回调
                stompClient.subscribe('/user/queue/sendUser', function(response) {
                    showResponse(response.body);
                });
            });
        }
        /*
        function connect() {
            //地址+端点路径，构建websocket链接地址,注意，对应config配置里的addEndpoint
            var socket = new SockJS(host+'/myUrl');
            stompClient = Stomp.over(socket);
            stompClient.connect({}, function(frame) {
                setConnected(true);
                console.log('Connected:' + frame);
                //监听的路径以及回调
                stompClient.subscribe('/topic/sendTopic', function(response) {
                    showResponse(response.body);
                });
            });
        }*/
        function disconnect() {
            if (stompClient != null) {
                stompClient.disconnect();
            }
            setConnected(false);
            console.log("Disconnected");
        }
        function send() {
            var name = $('#name').val();
            var message = $('#messgae').val();
            /*//发送消息的路径,由客户端发送消息到服务端
            stompClient.send("/sendServer", {}, message);
            */
            /*// 发送给所有广播sendTopic的人,客户端发消息，大家都接收，相当于直播说话 注：连接需开启 /topic/sendTopic
            stompClient.send("/sendAllUser", {}, message);
            */
            /* 这边需要注意，需要启动不同的前端html进行测试，需要改不同token ，例如 token=1234，token=4567
            * 然后可以通过写入name 为token  进行指定用户发送
            */
            stompClient.send("/sendMyUser", {}, JSON.stringify({name:name,message:message}));
        }
        function showResponse(message) {
            var response = $('#response');
            response.html(message);
        }
    </script>
</body>
</html>

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