springboot集成websocket全全全！！！

一、界面展示

二、前置了解

1.什么是websocket

WebSocket是一种在单个TCP连接上进行全双工通信的持久化协议。
全双工协议就是客户端可以给我们服务器发数据 服务器也可以主动给客户端发数据。

2.为什么有了http协议 还要websocket 协议

http协议是一种无状态，非持久化的单全双工应用层协议。
主要用于一问一答的方式交付信息，即客户端发送请求，服务器返回响应。这种模式适合于获取数据或者提交数据的场景。

所以http协议中，服务器无法主动给客户端发送数据，导致出现服务器数据状态发生改变，客户端无法感知。

针对上面的问题，http 勉强可以通过?定时轮询 和 长轮询 解决问题。

定时轮询：客户端不断地定时请求服务器, 询问数据状态变更的情况。
定时轮询的弊端：存在延时，浪费服务器资源和带宽，存在大量无效请求。

长轮询：拉长请求时间，客户端发送请求后，服务器在没有新数据时不会立即响应，而是等到有新数据时才返回响应。这种方法可以减少无效的请求，
长轮询的弊端：仍然需要频繁地建立和断开连接，且服务器需要维护未完成的请求，这可能会占用大量的服务器资源。

承上启下 所有最后我们websocket应运而生，它就是为了解决这个问题而设计的。
WebSocket协议可以实现全双工通信，即客户端和服务器可以在任何时候?相互?主动发送数据。此外，一旦WebSocket连接建立，客户端和服务器之间的连接将保持活动状态，直到被任何一方关闭。

三、附集成代码

1.引入pom依赖

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
        </dependency>

2.使用@ServerEndpoint创建WebSocket Endpoint

package com.ruoyi.framework.websocket;

import com.ruoyi.common.core.domain.model.LoginUser;
import com.ruoyi.common.utils.StringUtils;
import com.ruoyi.framework.config.WebSocketConfig;
import com.ruoyi.framework.web.service.TokenService;
import org.slf4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicLong;

import org.slf4j.LoggerFactory;

/**
 * @author qujingye
 * @Classname WebSocketServer
 * @Description  虽然@Component默认是单例模式的，但springboot还是会为每个websocket连接初始化一个bean
 * @Date 2023/12/19 16:11
 */
@Component
@ServerEndpoint(value = "/websocket/message", configurator = WebSocketConfig.class)
public class WebSocketServer {

    private static TokenService tokenService;

    @Autowired
    private void setOriginMessageSender(TokenService tokenService) {
        WebSocketServer.tokenService = tokenService;
    }

    /**
     * WebSocketServer 日志控制器
     */
    private static final Logger LOGGER = LoggerFactory.getLogger(WebSocketServer.class);

    private final static ConcurrentHashMap<Long, CopyOnWriteArrayList<Session>> sessionPool = new ConcurrentHashMap<>();

    private final static AtomicLong atomicLong = new AtomicLong(0L);


    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session) throws Exception {
        Long userId = parseUserId(session);
        System.out.println(userId);
        LOGGER.info("[WebSocket] 有新的连接, 当前用户id: {}", userId);
        if (userId == null) {
            return;
        }
        CopyOnWriteArrayList<Session> sessions = sessionPool.get(userId);
        //不存在其他人登陆
        if (null == sessions) {
            sessions = new CopyOnWriteArrayList<>();
        }
        sessions.add(session);
        sessionPool.put(userId, sessions);
        atomicLong.getAndIncrement();
        LOGGER.info("[WebSocket] 有新的连接, 当前连接数: {}", atomicLong.get());

    }

    /**
     * 连接关闭时处理
     */
    @OnClose
    public void onClose(Session session) {
        Long userId = parseUserId(session);
        if (userId == null) {
            return;
        }
        CopyOnWriteArrayList<Session> sessions = sessionPool.remove(userId);
        CopyOnWriteArrayList<Session> newSessions = new CopyOnWriteArrayList<>();
        for (Session s : sessions) {
            if (!s.getId().equals(session.getId())) {
                newSessions.add(s);
            }
        }
        sessionPool.put(userId, newSessions);
        atomicLong.getAndDecrement();
        LOGGER.info("[WebSocket] 连接断开, 当前连接数: {}", atomicLong.get());
    }

    /**
     * 抛出异常时处理
     */
    @OnError
    public void onError(Session session, Throwable exception) throws Exception {
        LOGGER.error("用户错误:,原因:" + exception.getMessage());
    }

    /**
     * 服务器接收到客户端消息时调用的方法
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        //把收到的消息发回去
        session.getAsyncRemote().sendText(message);
        LOGGER.info("message: {}", message);
    }


    /**
     * 给该用户id的全部发送消息
     */
    public void sendMessage(Long userId, String message) {
        CopyOnWriteArrayList<Session> sessions = sessionPool.get(userId);
        if (null == sessions || sessions.size() == 0) {
            return;
        }
        sessions.forEach(s -> s.getAsyncRemote().sendText(message));
    }

    /**
     * 获取用户id
     */
    private Long parseUserId(Session session) {
        String token = (String) session.getUserProperties().get(WebSocketConfig.WEBSOCKET_PROTOCOL);
        if (StringUtils.isNotEmpty(token)) {
            LoginUser loginUser = tokenService.getLoginUserByToken(token);
            if (loginUser != null) {
                return loginUser.getUserId();
            }
        }
        return null;
    }
}

3.定义WebSocketConfig

注入ServerEndpointExporter来自动注册端点

package com.ruoyi.framework.config;

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

import javax.websocket.HandshakeResponse;
import javax.websocket.server.HandshakeRequest;
import javax.websocket.server.ServerEndpointConfig;
import java.util.List;
import java.util.Map;

/**
 * @author qujingye
 * @Classname WebSocketConfig
 * @Description 继承服务器断点配置类
 * @Date 2023/12/19 16:08
 */
@Configuration
public class WebSocketConfig extends ServerEndpointConfig.Configurator {

    /**
     * WebSocket的协议头
     */
    public final static String WEBSOCKET_PROTOCOL = "Sec-Websocket-Protocol";

    /**
     * 注入ServerEndpointExporter，这个Bean会自动注册使用了@ServerEndpoint注解声明的WebSocket Endpoint。
     */
    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }


    /**
     * 建立握手时，连接前的操作
     */
    @Override
    public void modifyHandshake(ServerEndpointConfig sec, HandshakeRequest request, HandshakeResponse response) {
        // 这个用户属性userProperties 可以通过 session.getUserProperties()获取
        final Map<String, Object> userProperties = sec.getUserProperties();
        Map<String, List<String>> headers = request.getHeaders();
        List<String> protocol = headers.get(WEBSOCKET_PROTOCOL);
        // 存放自己想要的header信息
        if (protocol != null) {
            userProperties.put(WEBSOCKET_PROTOCOL, protocol.get(0));
        }


    }

    /**
     * 创建端点实例,也就是被@ServerEndpoint所标注的对象
     */
    @Override
    public <T> T getEndpointInstance(Class<T> clazz) throws InstantiationException {
        return super.getEndpointInstance(clazz);
    }

}

4.定义过滤器设置响应头

package com.ruoyi.framework.security.filter;

import com.ruoyi.common.utils.StringUtils;
import com.ruoyi.framework.config.WebSocketConfig;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * FileName:     com.admin.security.filter WebsocketFilter
 * Date:         2023/8/1 16:42
 *
 * @author Messylee
 */
@Order(1)
@Component
@WebFilter(filterName = "WebsocketFilter", urlPatterns = "/ws/**")
public class WebsocketFilter implements Filter {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        HttpServletRequest headers = (HttpServletRequest) servletRequest;
        String token = headers.getHeader(WebSocketConfig.WEBSOCKET_PROTOCOL);
        if (StringUtils.isNotEmpty(token)){
            response.setHeader(WebSocketConfig.WEBSOCKET_PROTOCOL, token);
        }
        filterChain.doFilter(servletRequest, servletResponse);
    }

}

5.vue前端界面代码

<template>
  <div class="app-container home">
    <el-row :gutter="20">
      <el-col :sm="24" :lg="24">
        <h1>集成websocket测试</h1>
      </el-col>
    </el-row>
    <el-row :gutter="20">
      <el-col :sm="24" :lg="24">
        <div>
          <el-input v-model="url" type="text" style="width: 20%" /> &nbsp;
          &nbsp;
          <el-button @click="join" type="primary">连接</el-button>
          <el-button @click="exit" type="danger">断开</el-button>
          <el-button @click="resetForm" type="success">重置</el-button>
          <br />
          <br />
          <el-input type="textarea" v-model="message" :rows="9" />
          <br />
          <br />
          <el-button type="success" @click="send">发送消息</el-button>
          <br />
          <br />
          返回内容
          <el-input type="textarea" v-model="text_content" :rows="9" />
          <br />
          <br />
        </div>
      </el-col>
    </el-row>
  </div>
</template>


<script>
import { getToken } from "@/utils/auth";

export default {
  name: "Index",
  data() {
    return {
      url: "ws://127.0.0.1:8080/websocket/message",
      message: "",
      text_content: "",
      ws: null,
      headers: {
        Authorization: "Bearer " + getToken(),
      },
    };
  },
  methods: {
    join() {
      const wsuri = this.url;
      // this.ws = new WebSocket(wsuri);
      this.ws = new WebSocket(wsuri, [getToken()]);
      const self = this;
      // 连接成功后调用
      this.ws.onopen = function (event) {
        self.text_content = self.text_content + "WebSocket连接成功!" + "\n";
      };
      this.ws.onerror = function (event) {
        self.text_content = self.text_content + "WebSocket连接发生错误!" + "\n";
      };
      // 接收后端消息
      this.ws.onmessage = function (event) {
        self.text_content = self.text_content + event.data + "\n";
      };
      // 关闭连接时调用
      this.ws.onclose = function (event) {
        self.text_content = self.text_content + "已经关闭连接!" + "\n";
      };
    },
    exit() {
      if (this.ws) {
        this.ws.close();
        this.ws = null;
      }
    },
    send() {
      if (this.ws) {
        this.ws.send(this.message);
      } else {
        alert("未连接到服务器");
      }
    },
    //重置
    resetForm() {
      this.message = "";
      this.text_content = "";
    },
  },
};
</script>