参考1：http://tech.dianwoda.com/2016/10/20/androidjin-cheng-bao-huo-gong-fang/
参考2：http://lioil.win/2017/12/19/Android-Alarm_Doze_Standby.html
参考3：https://www.jianshu.com/p/adbfea66e3ae
参考4：【时钟例子】http://godcoder.me/2016/05/25/%E5%85%B3%E4%BA%8EAndroid%E4%B8%AD%E8%AE%BE%E7%BD%AE%E9%97%B9%E9%92%9F%E7%9A%84%E7%9B%B8%E5%AF%B9%E6%AF%94%E8%BE%83%E5%AE%8C%E5%96%84%E7%9A%84%E8%A7%A3%E5%86%B3%E6%96%B9%E6%A1%88/