第一步：建立一個 WebSocket 連線

 wx.connectSocket({
      url: "wss://websocket.allhjs.com",
    })

第二步：監聽WebSocket連線開啟

    wx.onSocketOpen(res => {
      this.setData({ socketOpen: true })
    })

第三步： wx.onSocketOpen 回撥之後傳送訊息

 if (socketOpen) {
    wx.sendSocketMessage({
      data:msg
    })
  }
 

第四步：監聽伺服器返回的訊息

wx.onSocketMessage(function(res) {
  console.log('收到伺服器內容：' + res.data)
})

第五步：由於同時只能有2個websocket，所以頁面解除安裝要關閉websocket

onUnload:function(){
    wx.closeSocket();
  },

下面貼上專案中一個完整的程式碼

  //發表評論
  sendChat(){
    if (!this.data.chatInfo){
      util.showToast('評論內容不能為空'
 
,'none');
      return;
    }
    let params = {
      meetingId: this.data.meetingId,
      content: this.data.chatInfo
    }
    this.websocket(this.data.chatInfo,params);
  },
  //連線websocket
  websocket(msg,params){
    let socketOpen = this.data.socketOpen;
    let obj = {
      name: this.data.userInfo.nickName,
      userId
 
: this.data.userId,
      meetingId: this.data.meetingId,
      addTime: util.formatTime(new Date()),
      content: msg
    }
    if (socketOpen){
      wx.sendSocketMessage({
        data: "{'userId':" + wx.getStorageSync('userId') + ",'databagId':" + this.data.meetingId + ",'msg':" + msg + ",'name':" + this.data.userInfo.nickName + "}",
        success:r =>{
          util.request(api.sendChats, params).then(r => {
            this.setData({ chatInfo: '' })
          })
        },
        fail:err =>{
          util.showToast('伺服器已斷開','none')
          wx.connectSocket({
            url: "wss://websocket.allhjs.com?databagId=" + this.data.meetingId + "&userId=" + wx.getStorageSync('userId') + "&name=" + this.data.userInfo.nickName,
          })
          wx.onSocketOpen(res => {
            this.setData({ socketOpen: true })
          })
          console.log('err',err)
        }
      })
    }else{
      util.showToast('通訊錯誤,請返回重連','none')
    }
  },
  onLoad: function(options) {
    this.getActDeatil(options.id);
    this.setData({ userId: wx.getStorageSync('userId'),userInfo: wx.getStorageSync('userInfo'), meetingId: options.id })
    //建立websocket
    wx.connectSocket({
      url: "wss://websocket.allhjs.com?databagId=" + this.data.meetingId + "&userId=" + wx.getStorageSync('userId') + "&name=" + this.data.userInfo.nickName,
    })
    wx.onSocketOpen(res => {
      this.setData({ socketOpen: true })
    })

    wx.onSocketError(res => {
      console.log('WebSocket連線開啟失敗，請檢查！')
    })

    wx.onSocketMessage(res => {
      let chatList = this.data.chatList;
      let obj = JSON.parse(res.data);
      let params = {
        addTime: util.formatTime(new Date()),
        content: obj.msg,
        name: obj.name,
        userId: obj.userId
      }
      chatList.push(params);
      this.setData({ chatList })
      setTimeout(() => { this.setData({ toView: 'bottom' }) }, 1)
    })
  },
  onUnload:function(){
    wx.closeSocket();
  }