//   根据当前时间和随机数生成流水号
   randomNumber() {
    const now = new Date()
    let month = now.getMonth() + 1
    let day = now.getDate()
    let hour = now.getHours()
    let minutes = now.getMinutes()
    let seconds = now.getSeconds()
    month = this.setTimeDateFmt(month)
    hour = this.setTimeDateFmt(hour)
    minutes = this.setTimeDateFmt(minutes)
    seconds = this.setTimeDateFmt(seconds)
    return now.getFullYear().toString() + month.toString() + day + hour + minutes + seconds + (Math.round(Math.random() * 89 + 100)).toString()
   }