SpringBoot整合WebSocket和AOP的问题

背景

最近在项目上用了WebSocket，但是遇到了一个很奇怪的问题，应用启动时抛出

Failed to register @ServerEndpoint class

配置类

package com.smec.fin.config.websocket;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

/**
 * @Description:
 * @author: wei.wang
 * @since: 2020/7/28 10:29
 * @history: 1.2020/7/28 created by wei.wang
 */
@Configuration
public class WebSocketConfig {
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

接收连接的类

package com.smec.fin.service.impl;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * @Description:
 * @author: wei.wang
 * @since: 2020/7/28 10:46
 * @history: 1.2020/7/28 created by wei.wang
 */


@ServerEndpoint("/websocket")
@Component
public class WebSocketServer {

    private static Logger logger = LoggerFactory.getLogger(WebSocketServer.class);

    /**
     * 静态变量，用来记录当前在线连接数。
     */
    private static volatile int onlineCount = 0;

    /**
     * concurrent包的线程安全Set，用来存放每个客户端对应的WebSocket对象，目前只有一个客户端，所以使用Set
     */
    private static CopyOnWriteArraySet<WebSocketServer> webSocketSet = new CopyOnWriteArraySet<WebSocketServer>();


    /**
     * 与某个客户端的连接会话，需要通过它来给客户端发送数据
     */
    private Session session;


    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session) {
        this.session = session;
        //加入set中
        webSocketSet.add(this);

        //在线数加1
        addOnlineCount();
        logger.info("开始监听,当前在线人数为{}", getOnlineCount());
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        logger.info("有一连接关闭！当前在线人数为" + getOnlineCount());
        //从set中删除
        webSocketSet.remove(this);
        //在线数减1
        subOnlineCount();
        logger.info("有一连接关闭！当前在线人数为" + getOnlineCount());
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message 客户端发送过来的消息
     */
    @OnMessage
    public void onMessage(String message) {
        logger.info("收到信息:" + message);
        System.out.println("webSocketSet Size " + webSocketSet.size());
    }

    /**
     * 发送消息
     *
     * @param message
     */
    public void sendMessageToPad(String message) {
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }


    /**
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        logger.error("发生错误");
        error.printStackTrace();
    }

    /**
     * 实现服务器主动推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }

    public static synchronized int getOnlineCount() {
        return onlineCount;
    }

    public static synchronized void addOnlineCount() {
        WebSocketServer.onlineCount++;
    }

    public static synchronized void subOnlineCount() {
        WebSocketServer.onlineCount--;
    }
}

看起来都没问题，我们把异常信息都打出来

Caused by: javax.websocket.DeploymentException: Cannot deploy POJO class [com.smec.fin.service.impl.WebSocketServer$$EnhancerBySpringCGLIB$$6b71ea8] as it is not annotated with @ServerEndpoint
    at org.apache.tomcat.websocket.server.WsServerContainer.addEndpoint(WsServerContainer.java:245)
    at org.apache.tomcat.websocket.server.WsServerContainer.addEndpoint(WsServerContainer.java:228)
    at org.springframework.web.socket.server.standard.ServerEndpointExporter.registerEndpoint(ServerEndpointExporter.java:156)
    ... 17 common frames omitted

问题原因

问题定位到WsServerContainer.java:245行，打上断点，我们发现pojo被代理了，其实根据打印日志com.smec.fin.service.impl.WebSocketServer$$EnhancerBySpringCGLIB$$6b71ea8也可以看出来，使用了CGLIB代理，那么问题就很明显了，此类被AOP做了代理，在AOP中将此类移除就可以了。

正常的pojo

被代理的pojo

AOP配置

将WebSocketServer类从AOP中移除，项目即可正常启动

    @AfterThrowing(pointcut = "execution( * com.smec.fin.service..*.*(..)) && !execution(* com.smec.fin.service.impl.WebSocketServer.*(..))", throwing = "e")
    public void afterThrowing(JoinPoint joinPoint, Throwable e) {
        logger.error("Exception in {}.{}() with cause = {}", joinPoint.getSignature().getDeclaringTypeName(),
                joinPoint.getSignature().getName(), e.getCause() != null ? e.getCause() : "NULL");
    }