java 有没有什么好办法可以得到下周三的日期？

Is there a good way to get the date of the coming Wednesday?

提问by user256239

Is there a good way to get the date of the coming Wednesday? That is, if today is Tuesday, I want to get the date of Wednesday in this week; if today is Wednesday, I want to get the date of next Wednesday; if today is Thursday, I want to get the date of Wednesday in the following week.

有没有什么好办法可以得到下周三的日期？也就是说，如果今天是星期二，我想得到这周星期三的日期；如果今天是星期三，我想得到下星期三的日期；如果今天是星期四，我想在下周获得星期三的日期。

Thanks.

谢谢。

回答by polygenelubricants

The basic algorithm is the following:

基本算法如下：

• Get the current date
• Get its day of week
• Find its difference with Wednesday
• If the difference is not positive, add 7 (i.e. insist on next coming/future date)
• Add the difference

• 获取当前日期
• 获取它的星期几
• 找出它与星期三的区别
• 如果差值不是正数，加7（即坚持下一个来/未来日期）
• 添加差异

Here's a snippet to show how to do this with java.util.Calendar:

这是一个片段，用于展示如何使用java.util.Calendar：

import java.util.Calendar;

public class NextWednesday {
    public static Calendar nextDayOfWeek(int dow) {
        Calendar date = Calendar.getInstance();
        int diff = dow - date.get(Calendar.DAY_OF_WEEK);
        if (diff <= 0) {
            diff += 7;
        }
        date.add(Calendar.DAY_OF_MONTH, diff);
        return date;
    }
    public static void main(String[] args) {
        System.out.printf(
            "%ta, %<tb %<te, %<tY",
            nextDayOfWeek(Calendar.WEDNESDAY)
        );
    }
}

Relative to my here and now, the output of the above snippet is "Wed, Aug 18, 2010".

相对于我的此时此地，上面代码片段的输出是"Wed, Aug 18, 2010".

API links

接口链接

• java.util.Calendar
• java.util.Formatter- for the formatting string syntax

• java.util.Calendar
• java.util.Formatter- 用于格式化字符串语法

回答by Unknown

tl;dr

tl;博士

LocalDate                        // Represent a date-only value, without time-of-day and without time zone.
.now()                           // Capture the current date as seen in the wall-clock time used by the people of a specific region (a time zone). The JVM's current default time zone is used here. Better to specify explicitly your desired/expected time zone by passing a `ZoneId` argument. Returns a `LocalDate` object.
.with(                           // Generate a new `LocalDate` object based on values of the original but with some adjustment. 
    TemporalAdjusters            // A class that provides some handy pre-defined implementations of `TemporalAdjuster` (note the singular) interface.
    .next(                       // An implementation of `TemporalAdjuster` that jumps to another date on the specified day-of-week.
        DayOfWeek.WEDNESDAY      // Pass one of the seven predefined enum objects, Monday-Sunday.
    )                            // Returns an object implementing `TemporalAdjuster` interface.
)                                // Returns a `LocalDate` object.

Details

细节

Using Java8 Date time APIyou can easily find the coming Wednesday.

使用Java8 日期时间 API，您可以轻松找到即将到来的星期三。

LocalDate nextWed = LocalDate.now().with(TemporalAdjusters.next(DayOfWeek.WEDNESDAY));

next(DayOfWeek dayOfWeek) - Returns the next day-of-week adjuster, which adjusts the date to the first occurrence of the specified day-of-week after the date being adjusted.

next(DayOfWeek dayOfWeek) - 返回下一个星期调整器，它将日期调整为调整日期后指定星期几的第一次出现。

Suppose If you want to get previous Wednesday then,

假设如果你想获得上一个星期三，那么

LocalDate prevWed = LocalDate.now().with(TemporalAdjusters.previous(DayOfWeek.WEDNESDAY));

previous(DayOfWeek dayOfWeek) - Returns the previous day-of-week adjuster, which adjusts the date to the first occurrence of the specified day-of-week before the date being adjusted.

previous(DayOfWeek dayOfWeek) - 返回上一个星期调整器，它将日期调整为在调整日期之前指定星期几的第一次出现。

Suppose If you want to get next or current Wednesday then

假设如果你想得到下一个或当前的星期三，那么

LocalDate nextOrSameWed = LocalDate.now().with(TemporalAdjusters.nextOrSame(DayOfWeek.WEDNESDAY));

nextOrSame(DayOfWeek dayOfWeek) - Returns the next-or-same day-of-week adjuster, which adjusts the date to the first occurrence of the specified day-of-week after the date being adjusted unless it is already on that day in which case the same object is returned.

nextOrSame(DayOfWeek dayOfWeek) - 返回下一个或同一个星期的调整器，它将日期调整到被调整的日期之后指定星期几的第一次出现，除非它已经在那个日期如果返回相同的对象。

Edit: You can also pass ZoneId to get the current date from the system clock in the specified time-zone.

编辑：您还可以通过 ZoneId 从指定时区的系统时钟获取当前日期。

ZoneId zoneId = ZoneId.of("UTC");
LocalDate nextWed = LocalDate.now(zoneId).with(TemporalAdjusters.next(DayOfWeek.WEDNESDAY));

For more information refer TemporalAdjusters

有关更多信息，请参阅TemporalAdjusters

回答by Yishai

Using JodaTime:

使用 JodaTime：

    LocalDate date = new LocalDate(System.currentTimeMillis());
    Period period = Period.fieldDifference(date, date.withDayOfWeek(DateTimeConstants.WEDNESDAY));
    int days = period.getDays();
    if (days < 1) {
        days = days + 7;
    }
    System.out.println(date.plusDays(days));

回答by EboMike

Use java.util.Calendar. You get the current date/time like this:

使用 java.util.Calendar。您可以像这样获得当前日期/时间：

Calendar date = Calendar.getInstance();

From there, get date.get(Calendar.DAY_OF_WEEK)to get the current day of week and get the difference to Calendar.WEDNESDAYand add it.

从那里，获取date.get(Calendar.DAY_OF_WEEK)当前星期几并获取差异Calendar.WEDNESDAY并添加它。

回答by Utsav Gupta

Calendar c= Calendar.getInstance();
c.set(Calendar.DAY_OF_WEEK, Calendar.WEDNESDAY);
c.add(Calendar.DAY_OF_MONTH, 7);
c.getTime();

回答by Soubhab Pathak

public static void nextWednesday() throws ParseException 
    {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

        Calendar calendar = Calendar.getInstance();
        calendar.setTime(new Date());
        int weekday = calendar.get(Calendar.DAY_OF_WEEK);
        int days = Calendar.WEDNESDAY - weekday;
        if (days < 0)
        {
            days += 7;
        }
        calendar.add(Calendar.DAY_OF_YEAR, days);

        System.out.println(sdf.format(calendar.getTime()));
    }