How to reduce one month from current date and stor

问题:

How to reduce one month from current date and want to sore in java.util.Date variable im using this code but it's shows error in 2nd line

 java.util.Date da = new Date();
 da.add(Calendar.MONTH, -1); //error

How to store this date in java.util.Date variable?

回答1:

Use Calendar:

Calendar cal = Calendar.getInstance();
cal.add(Calendar.MONTH, -1);
Date result = cal.getTime();

回答2:

Starting from Java 8, the suggested way is to use the Date-Time API rather than Calendar.

If you want a Date object to be returned:

Date date = Date.from(ZonedDateTime.now().minusMonths(1).toInstant());

If you don't need exactly a Date object, you can use the classes directly, provided by the package, even to get dates in other time-zones:

ZonedDateTime dateInUTC = ZonedDateTime.now(ZoneId.of("Pacific/Auckland")).minusMonths(1);

回答3:

Calendar calNow = Calendar.getInstance()

// adding -1 month
calNow.add(Calendar.MONTH, -1);

// fetching updated time
Date dateBeforeAMonth = calNow.getTime();

回答4:

you can use Calendar

    java.util.Date da = new Date();
    Calendar cal = Calendar.getInstance();
    cal.setTime(da);
    cal.add(Calendar.MONTH, -1);
    da = cal.getTime();

回答5:

Using JodaTime :

Date date = new DateTime().minusMonths(1).toDate();

JodaTime provides a convenient API for date manipulation.

Note that similar Date API will be introduced in JDK8 with the JSR310.

回答6:

Using new java.time package in Java8 and Java9

import java.time.LocalDate;

LocalDate mydate = LocalDate.now(); // Or whatever you want
mydate = mydate.minusMonths(1);

The advantage to using this method is that you avoid all the issues about varying month lengths and have more flexibility in adjusting dates and ranges. The Local part also is Timezone smart so it's easy to convert between them.

As an aside, using java.time you can also get the day of the week, day of the month, all days up to the last of the month, all days up to a certain day of the week, etc.

mydate.plusMonths(1);
mydate.with(TemporalAdjusters.next(DayOfWeek.SUNDAY)).getDayOfMonth();
mydate.with(TemporalAdjusters.lastDayOfMonth());