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

您还可以使用Duration类。如。

Date currentDate = new Date();
Date oneDayFromCurrentDate = new Date(currentDate.getTime() - Duration.ofDays(1).toMillis());

其他回答

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();

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
*/

简单地使用这个来获取300天之前的日期,用你的日期替换300天:

Date date = new Date(); // Or where ever you get it from
Date daysAgo = new DateTime(date).minusDays(300).toDate();

在这里,

DateTime 是 org.joda.time.DateTime;

Date是java.util.Date

您可以使用SimpleDateFormat轻松地减去日历

 public static String subtractDate(String time,int subtractDay) throws ParseException {


        Calendar cal = Calendar.getInstance();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm", Locale.ENGLISH);
        cal.setTime(sdf.parse(time));
        cal.add(Calendar.DATE,-subtractDay);
        String wantedDate = sdf.format(cal.getTime());

        Log.d("tag",wantedDate);
        return wantedDate;

    }

您还可以使用Duration类。如。

Date currentDate = new Date();
Date oneDayFromCurrentDate = new Date(currentDate.getTime() - Duration.ofDays(1).toMillis());