我想做的事情是:
Date date = new Date(); // current date
date = date - 300; // substract 300 days from current date and I want to use this "date"
怎么做呢?
我想做的事情是:
Date date = new Date(); // current date
date = date - 300; // substract 300 days from current date and I want to use this "date"
怎么做呢?
当前回答
Java 8及以上版本
Java 8的日期时间API更改,使用LocalDate
LocalDate date = LocalDate.now().minusDays(300);
同样地,你可以有
LocalDate date = someLocalDateInstance.minusDays(300);
java.util.Date <——> java.time.LocalDateTime之间的转换请参阅https://stackoverflow.com/a/23885950/260990
Date in = new Date();
LocalDateTime ldt = LocalDateTime.ofInstant(in.toInstant(), ZoneId.systemDefault());
Date out = Date.from(ldt.atZone(ZoneId.systemDefault()).toInstant());
java7及更早版本
使用Calendar的add()方法
Calendar cal = Calendar.getInstance();
cal.setTime(dateInstance);
cal.add(Calendar.DATE, -30);
Date dateBefore30Days = cal.getTime();
其他回答
java8时间API:
Instant now = Instant.now(); //current date
Instant before = now.minus(Duration.ofDays(300));
Date dateBefore = Date.from(before);
正如你所看到的,这里有很多你可以做的操作。这里有一个例子说明你可以做什么!
DateFormat dateFormat = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
Calendar cal = Calendar.getInstance();
//Add one day to current date.
cal.add(Calendar.DATE, 1);
System.out.println(dateFormat.format(cal.getTime()));
//Substract one day to current date.
cal = Calendar.getInstance();
cal.add(Calendar.DATE, -1);
System.out.println(dateFormat.format(cal.getTime()));
/* Can be Calendar.DATE or
* Calendar.MONTH, Calendar.YEAR, Calendar.HOUR, Calendar.SECOND
*/
有了Java 8,现在真的很简单:
LocalDate date = LocalDate.now().minusDays(300);
关于新api的指南可以在这里找到。
Java 8及以上版本
Java 8的日期时间API更改,使用LocalDate
LocalDate date = LocalDate.now().minusDays(300);
同样地,你可以有
LocalDate date = someLocalDateInstance.minusDays(300);
java.util.Date <——> java.time.LocalDateTime之间的转换请参阅https://stackoverflow.com/a/23885950/260990
Date in = new Date();
LocalDateTime ldt = LocalDateTime.ofInstant(in.toInstant(), ZoneId.systemDefault());
Date out = Date.from(ldt.atZone(ZoneId.systemDefault()).toInstant());
java7及更早版本
使用Calendar的add()方法
Calendar cal = Calendar.getInstance();
cal.setTime(dateInstance);
cal.add(Calendar.DATE, -30);
Date dateBefore30Days = cal.getTime();
在Java 8中,你可以这样做:
Instant inst = Instant.parse("2018-12-30T19:34:50.63Z");
// subtract 10 Days to Instant
Instant value = inst.minus(Period.ofDays(10));
// print result
System.out.println("Instant after subtracting Days: " + value);