先看下效果图

先看下后台返回的数据结构是什么样子的

{
    "map": {
        "title": "地区销量趋势",
        "base": 310,
        "unit": "万",
        "data": [{
            "name": "上海",
            "data": ["155.13","154.65","171.46","164.38","237.23","300.65","240.29","232.07","193.31","136.70","48.64","90.20"]
        }, {
            "name": "北京",
            "data": ["86.25","33.80","145.58","21.79","176.09","132.41","291.05","191.89","151.54","94.25","141.75","157.14"]
        }, {
            "name": "深圳",
            "data": ["143.94","186.29","183.64","251.48","195.48","152.16","52.47","184.12","203.79","39.16","56.37","161.64"]
        }, {
            "name": "广州",
            "data": ["57.60","77.61","307.24","165.05","175.41","276.88","269.04","296.11","105.31","283.39","134.08","265.38"]
        }, {
            "name": "重庆",
            "data": ["200.82","215.56","249.80","222.67","216.98","60.12","309.68","273.35","150.99","251.97","26.15","186.99"]
        }]
    },
    "seller": {
        "title": "商家销量趋势",
        "base": 120,
        "unit": "万",
        "data": [{
            "name": "商家1",
            "data": ["33.00","86.07","28.77","34.29","102.45","0.30","50.50","21.70","25.41","25.71","66.90","63.29"]
        }, {
            "name": "商家2",
            "data": ["12.83","102.42","37.37","95.55","45.45","112.72","113.53","106.41","75.67","113.91", "37.32", "28.04"]
        }, {
            "name": "商家3",
            "data": ["73.54","40.92","89.81","113.41","76.34","107.15","55.61","0.33","106.29","78.30","98.05","38.67"]
        }, {
            "name": "商家4",
            "data": ["47.19","73.57","44.60","84.03","62.82","15.65","64.72","88.98","29.25","5.41","79.11","118.46"]
        }, {
            "name": "商家5",
            "data": ["74.84","116.45","107.69","11.03","17.31","42.22","97.60","108.64","43.87","110.65","5.96","38.41"]
        }]
    },
    "commodity": {
        "title": "商品销量趋势",
        "base": 50,
        "unit": "万",
        "data": [{
            "name": "女装",
            "data": ["47.71","13.34","19.30","7.93","41.93","23.01","22.63","26.91","0.62","39.23","48.74","29.48"]
        }, {
            "name": "手机数码",
            "data": ["46.66","46.52","23.65","1.73","44.26","47.07","17.86","40.20","3.78","31.46","28.01","8.63"]
        }, {
            "name": "男装",
            "data": ["26.98","30.71","42.59","29.50","26.86","17.65","30.15","15.85","9.28","30.20","32.35","34.46"]
        }, {
            "name": "大家电",
            "data": ["20.26","46.23","43.84","46.75","28.29","32.36","45.30","16.73","40.40","45.07","29.86","41.92"]
        }, {
            "name": "美妆护肤",
            "data": ["7.58","23.66","39.78","30.20","25.72","36.20","47.55","35.39","27.85","37.56","16.91", "3.91"]
        }]
    },
    "common": {
        "month": ["一月", "二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月"]
    },
    "type": [{
        "key": "map",
        "text": "地区销量趋势"
    }, {
        "key": "seller",
        "text": "商家销量趋势"
    }, {
        "key": "commodity",
        "text": "商品销量趋势"
    }]
}

好了，开始实现前端的代码

html

 <div class="com-page">
	<div class="com-container">
  <div class="title" :style="comStyle">
      <span>{
   
   { '▎ ' +  showTitle }}</span>
      <span class="iconfont title-icon" :style="comStyle"  @click="showChoice = !showChoice">&#xe6eb;</span>
      <div class="select-con" v-show="showChoice" :style="marginStyle">
        <div class="select-item" v-for="item in selectTypes" :key="item.key" @click="handleSelect(item.key)">
          {
   
   { item.text }}
        </div>
      </div>
    </div>
    <div class="com-chart" ref="trend_ref"></div>
  </div>
	</div>

css

html,body,#app{
  width: 100%;
  height: 100%;
  padding: 0;
  margin: 0;
  overflow: hidden;
}
.com-page {
  width: 100%;
  height: 100%;
  overflow: hidden;
}

.com-container {
  position: relative;
  width: 100%;
  height: 100%;
  overflow: hidden;
}

.com-chart {
  width: 100%;
  height: 100%;
  overflow: hidden;
}
.title {
  position: absolute;
  left: 20px;
  top: 20px;
  z-index: 10;
  color: white;
  .title-icon {
    margin-left: 10px;
    cursor: pointer;
  }
  .select-con {
    background-color: #222733;
  }
}

data

data() {
    return {
      chartInstance: null,  //初始化echartInstance对象
      allData: null,   //接收的后台数据
      showChoice: false, // 是否显示可选项
      choiceType: 'map', // 显示的数据类型
      titleFontSize: 0 // 指明标题的字体大小
    };
  },

methods

initChart方法

 //初始化echartInstance对象
 //chalk是我们定义的主题，echarts官方有案例，怎么使用可以百度一下,不喜欢可以直接删掉
 this.chartInstance = this.$echarts.init(this.$refs.trend_ref, "chalk");
      const initOption = {
        grid: {
          left: "3%",
          top: "35%",
          right: "4%",
          bottom: "1%",
          containLabel: true,
        },
        tooltip: {
          trigger: "axis",
        },
        legend: {
          left: 20,
          top: "15%",
          icon: "circle",
        },
        xAxis: {
          type: "category",
          boundaryGap: false,
        },
        yAxis: {
          type: "value",
        },
      };
      this.chartInstance.setOption(initOption);
    },

getData方法

这里还是用http请求获取的数据，后面我再讲怎么用WebSocket获取我们的数据

async getData(){
 const { data: res } = await this.$http.get("trend");
 console.log(res);
  this.allData = res;
  this.updateChart();
}

updateChart

//更新数据
 updateChart() {
      // 半透明的颜色值
      const colorArr1 = [
        'rgba(11, 168, 44, 0.5)',
        'rgba(44, 110, 255, 0.5)',
        'rgba(22, 242, 217, 0.5)',
        'rgba(254, 33, 30, 0.5)',
        'rgba(250, 105, 0, 0.5)'
      ]
      // 全透明的颜色值
      const colorArr2 = [
        'rgba(11, 168, 44, 0)',
        'rgba(44, 110, 255, 0)',
        'rgba(22, 242, 217, 0)',
        'rgba(254, 33, 30, 0)',
        'rgba(250, 105, 0, 0)'
      ]
      //处理数据
      //类目轴的数据
      const timeArr = this.allData.common.month;
      //y轴的数据,series下的数据
      const valueArr = this.allData[this.choiceType].data;
      const seriesArr = valueArr.map((item,index) => {
        return {
          name: item.name,
          type: "line",
          data: item.data,
          stack: "map",
          areaStyle:{
             color: new this.$echarts.graphic.LinearGradient(0, 0, 0, 1, [
              {
                offset: 0,
                color: colorArr1[index]
              }, // %0的颜色值
              {
                offset: 1,
                color: colorArr2[index]
              } // 100%的颜色值
            ])
          }
        };
      });
      //图例的数据
      const legendArr = valueArr.map((item) => {
        return item.name;
      });
      const dataOption = {
        xAxis: {
          data: timeArr,
        },
        legend: {
          data: legendArr,
        },
        series: seriesArr,
      };
      this.chartInstance.setOption(dataOption);
    },

screenAdapter

//适配屏幕
 screenAdapter() {
      this.titleFontSize = this.$refs.trend_ref.offsetWidth / 100 * 3.6
      const adapterOption = {
        legend: {
          itemWidth: this.titleFontSize,
          itemHeight: this.titleFontSize,
          itemGap: this.titleFontSize,
          textStyle: {
            fontSize: this.titleFontSize / 2
          }
        }
      };
      this.chartInstance.setOption(adapterOption);
      this.chartInstance.resize();
    }
  },

handleSelect

//选择标题

handleSelect(currentType){
       this.choiceType = currentType
       this.updateChart()
       this.showChoice = false
    }

mounted

  mounted() {
    this.initChart()
    this.getData()
    window.addEventListener('resize', this.screenAdapter)
    this.screenAdapter()
  },

destroyed

  destroyed() {
    window.removeEventListener('resize', this.screenAdapter)
  },

好了，完事，下面我把如何用WebSocket获取数据说一下

封装了一个WebSocket

export default class SocketService {
  /**
   * 单例
   */
  static instance = null
  static get Instance() {
    if (!this.instance) {
      this.instance = new SocketService()
    }
    return this.instance
  }

  // 和服务端连接的socket对象
  ws = null

  // 存储回调函数
  callBackMapping = {}

  // 标识是否连接成功
  connected = false

  // 记录重试的次数
  sendRetryCount = 0

  // 重新连接尝试的次数
  connectRetryCount = 0

  //  定义连接服务器的方法
  connect() {
    // 连接服务器
    if (!window.WebSocket) {
      return console.log('您的浏览器不支持WebSocket')
    }
    this.ws = new WebSocket('ws://localhost:9998')

    // 连接成功的事件
    this.ws.onopen = () => {
      console.log('连接服务端成功了')
      this.connected = true
      // 重置重新连接的次数
      this.connectRetryCount = 0
    }
    // 1.连接服务端失败
    // 2.当连接成功之后, 服务器关闭的情况
    this.ws.onclose = () => {
      console.log('连接服务端失败')
      this.connected = false
      this.connectRetryCount++
      setTimeout(() => {
        this.connect()
      }, 500 * this.connectRetryCount)
    }
    // 得到服务端发送过来的数据
    this.ws.onmessage = msg => {
      console.log('从服务端获取到了数据')
      // 真正服务端发送过来的原始数据时在msg中的data字段
      // console.log(msg.data)
      const recvData = JSON.parse(msg.data)
      const socketType = recvData.socketType
      // 判断回调函数是否存在
      if (this.callBackMapping[socketType]) {
        const action = recvData.action
        if (action === 'getData') {
          const realData = JSON.parse(recvData.data)
          this.callBackMapping[socketType].call(this, realData)
        } else if (action === 'fullScreen') {
          this.callBackMapping[socketType].call(this, recvData)
        } else if (action === 'themeChange') {
          this.callBackMapping[socketType].call(this, recvData)
        }
      }
    }
  }

  // 回调函数的注册
  registerCallBack (socketType, callBack) {
    this.callBackMapping[socketType] = callBack
  }

  // 取消某一个回调函数
  unRegisterCallBack (socketType) {
    this.callBackMapping[socketType] = null
  }

  // 发送数据的方法
  send (data) {
    // 判断此时此刻有没有连接成功
    if (this.connected) {
      this.sendRetryCount = 0
      this.ws.send(JSON.stringify(data))
    } else {
      this.sendRetryCount++
      setTimeout(() => {
        this.send(data)
      }, this.sendRetryCount * 500)
    }
  }
}

在main.js中进行连接，挂载原型

//对服务端进行连接
import SocketService from '../utils/socket_service'
SocketService.Instance.connect()
// 其他的组件  this.$socket
Vue.prototype.$socket = SocketService.Instance

然后在组件中

  created() {
    //在组件创建完成之后进行回调函数注册
    this.$socket.registerCallBack('trendData',this.getData)
  },
  
   mounted() {
    this.initChart();
    //发送数据给服务器，告诉服务器，我现在需要数据
    this.$socket.send({
      action:'getData',
      socketType:'trendData',
      chartName:'trend',
      value:''
    })
    window.addEventListener("resize", this.screenAdapter);
    this.screenAdapter();
  },
  
  destroyed() {
    window.removeEventListener("resize", this.screenAdapter);
    //取消
    this.$socket.unRegisterCallBack('trendData')
  },
  methods:{
  //res就是服务端发送给客户端的图表数据
    getData(res) {
      this.allData = res;
      this.updateChart();
    },
    }

这样就实现了后端发生变化，前端即时更新视图

至于为什么WebSocket这样封装，因为后台定了规则

const path = require('path')
const fileUtils = require('../utils/file_utils')
const WebSocket = require('ws')
// 创建WebSocket服务端的对象, 绑定的端口号是9998
const wss = new WebSocket.Server({
  port: 9998
})
// 服务端开启了监听
module.exports.listen = () => {
  // 对客户端的连接事件进行监听
  // client:代表的是客户端的连接socket对象
  wss.on('connection', client => {
    console.log('有客户端连接成功了...')
    // 对客户端的连接对象进行message事件的监听
    // msg: 由客户端发给服务端的数据
    client.on('message',async msg => {
      console.log('客户端发送数据给服务端了: ' + msg)
      let payload = JSON.parse(msg)
      const action = payload.action
      if (action === 'getData') {
        let filePath = '../data/' + payload.chartName + '.json'
        // payload.chartName // trend seller map rank hot stock
        filePath = path.join(__dirname, filePath)
        const ret = await fileUtils.getFileJsonData(filePath)
        // 需要在服务端获取到数据的基础之上, 增加一个data的字段
        // data所对应的值,就是某个json文件的内容
        payload.data = ret
        client.send(JSON.stringify(payload))
      } else {
        // 原封不动的将所接收到的数据转发给每一个处于连接状态的客户端
        // wss.clients // 所有客户端的连接
        wss.clients.forEach(client => {
          client.send(msg)
        })
      }
      // 由服务端往客户端发送数据
      // client.send('hello socket from backend')
    })
  })
}

有不懂的可以去我的github查看源代码，前后端都有，后端必须启动，前端才有显示，WebSocket我只配了Trend组件，其他全部一样的操作

github项目地址https://github.com/lsh555/Echarts

项目详情如下