2019/10/31-Date与String、Long三者的转换

<一>.
date 与 string 类型的转换：
1.date => string

Date date = new Date();
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
String dateStr = dateFormat.format(date);
System.out.println(dateStr);

2.string => date

SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
String s= "2011-07-09 "; //时间格式要一致
Date date =  dateFormat.parse(s);

<二>.
date 与long类型转换
1.date => long

long milliSeconds = 1571814689000l;
Date date = new Date();
date.setTime(milliSeconds);

2.long => date

Date date = new Date();
long  dateLong = date.getTime();