date->long
long time1 = System.currentTimeMillis();//获得系统当前时间
long time2 = date.getTime();//date为Date格式的变量
long->date
long time = (long)1514339596672;//报错,The literal 1514336569739 of type int is out of range
1514339596672被默认识别为int格式,然后又超范围,因此:
long time=Long.valueOf("1514336569739");
Date date=new Date(time);
用这种方式解决了