如何从java中减去当前日期的n天？ [重复]

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• How to subtract X days from a date using Java calendar? 9 answers

如何使用Java日历从日期中减去X天? 9个答案

I want to subtract n days from the current date in Java.

我想在Java中减去当前日期的n天。

How do I do that?

我怎么做?

5 个解决方案

#1

You don't have to use Calendar. You can just play with timestamps :

您不必使用日历。你可以玩时间戳:

Date d = initDate();//intialize your date to any date 
Date dateBefore = new Date(d.getTime() - n * 24 * 3600 * 1000 l ); //Subtract n days   

UPDATE DO NOT FORGET TO ADD "l" for long by the end of 1000.

更新不要忘记在1000年底之前添加“l”。

Please consider the below WARNING:

请考虑以下警告:

Adding 1000*60*60*24 milliseconds to a java date will once in a great while add zero days or two days to the original date in the circumstances of leap seconds, daylight savings time and the like. If you need to be 100% certain only one day is added, this solution is not the one to use.

在闰秒,夏令时等情况下,向java日期添加1000 * 60 * 60 * 24毫秒将在很长一段时间内添加零天或两天到原始日期。如果您需要100%确定只添加一天,则此解决方案不是使用的解决方案。

#2

this will subtract ten days of the current date (before Java 8):

这将减去当前日期的十天(在Java 8之前):

int x = -10;
Calendar cal = GregorianCalendar.getInstance();
cal.add( Calendar.DAY_OF_YEAR, x);
Date tenDaysAgo = cal.getTime();

If you're using Java 8 you can make use of the new Date & Time API (http://www.oracle.com/technetwork/articles/java/jf14-date-time-2125367.html):

如果您使用的是Java 8,则可以使用新的Date&Time API(http://www.oracle.com/technetwork/articles/java/jf14-date-time-2125367.html):

LocalDate tenDaysAgo = LocalDate.now().minusDays(10);

For converting the new to the old types and vice versa see: Converting between java.time.LocalDateTime and java.util.Date

要将新类型转换为旧类型,反之亦然,请参阅:在java.time.LocalDateTime和java.util.Date之间进行转换

#3

I found this perfect solution and may useful, You can directly get in format as you want:

我找到了这个完美的解决方案并且可能很有用,您可以根据需要直接获取格式:

Calendar cal = Calendar.getInstance();
cal.add(Calendar.DATE, -90); // I just want date before 90 days. you can give that you want.

SimpleDateFormat s = new SimpleDateFormat("yyyy-MM-dd"); // you can specify your format here...
Log.d("DATE","Date before 90 Days: " + s.format(new Date(cal.getTimeInMillis())));

Thanks.

#4

for future use find day of the week ,deduct day and display the deducted day using date.

public static void main(String args[]) throws ParseException {

String[] days = { "Sunday", "Monday", "Tuesday", "Wednesday",
        "Thursday", "Friday", "Saturday" };
SimpleDateFormat format1 = new SimpleDateFormat("dd/MM/yyyy");
Date dt1 = format1.parse("20/10/2013");

Calendar c = Calendar.getInstance();
c.setTime(dt1);
int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);
long diff = Calendar.getInstance().getTime().getTime() ;
System.out.println(dayOfWeek);

switch (dayOfWeek) {

case 6:
    System.out.println(days[dayOfWeek - 1]);
    break;
case 5:

    System.out.println(days[dayOfWeek - 1]);
    break;      
case 4:
    System.out.println(days[dayOfWeek - 1]);
    break;
case 3:

    System.out.println(days[dayOfWeek - 1]);
    break;
case 2:
    System.out.println(days[dayOfWeek - 1]);
    break;
case 1:

    System.out.println(days[dayOfWeek - 1]);

     diff = diff -(dt1.getTime()- 3 );
     long valuebefore = dt1.getTime();
     long valueafetr = dt1.getTime()-2;
     System.out.println("DATE IS befor subtraction :"+valuebefore);
     System.out.println("DATE IS after subtraction :"+valueafetr);

     long x= dt1.getTime()-(2 * 24 * 3600 * 1000);
     System.out.println("Deducted date to find firday is - 2 days form Sunday :"+new Date((dt1.getTime()-(2*24*3600*1000))));
     System.out.println("DIffrence from now on is :"+diff);
        if(diff > 0) {

            diff = diff / (1000 * 60 * 60 * 24);
            System.out.println("Diff"+diff);
            System.out.println("Date is Expired!"+(dt1.getTime() -(long)2));
        }

    break;
}
}

#5

As @Houcem Berrayana say

正如@Houcem Berrayana所说

If you would like to use n>24 then you can use the code like:

如果你想使用n> 24,那么你可以使用如下代码:

Date dateBefore = new Date((d.getTime() - n * 24 * 3600 * 1000) - n * 24 * 3600 * 1000); 

Suppose you want to find last 30 days date, then you'd use:

假设您要查找最近30天的日期,那么您将使用:

Date dateBefore = new Date((d.getTime() - 24 * 24 * 3600 * 1000) - 6 * 24 * 3600 * 1000);