Java - 如何计算每周的第一天和最后一天
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/3023267/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Java - How to calculate the first and last day of each week
提问by user236501
I'm trying to create a weekly calendar that looks like this: http://dhtmlx.com/docs/products/dhtmlxScheduler/sample_basic.html
我正在尝试创建一个看起来像这样的每周日历：http: //dhtmlx.com/docs/products/dhtmlxScheduler/sample_basic.html
How can I calculate every week date? For example, this week is:
如何计算每周的日期？例如，本周是：
Monday - Sunday
7 June, 8 June, 9 June, 10 June, 11 June, 12 June, 13 June
周一至周日
6月7日、6月8日、6月9日、6月10日、6月11日、6月12日、6月13日
采纳答案by Jesper
I guess this does what you want:
我想这可以满足您的要求：
// Get calendar set to current date and time
Calendar c = Calendar.getInstance();
// Set the calendar to monday of the current week
c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
// Print dates of the current week starting on Monday
DateFormat df = new SimpleDateFormat("EEE dd/MM/yyyy");
for (int i = 0; i < 7; i++) {
System.out.println(df.format(c.getTime()));
c.add(Calendar.DATE, 1);
}
回答by user334583
回答by Sjoerd
If you know which day it is (Friday) and the current date (June 11), you can calculate the other days in this week.
如果您知道是哪一天（星期五）和当前日期（6 月 11 日），则可以计算出本周的其他天数。
回答by kgiannakakis
回答by Nikita Rybak
First day of this week.
本周的第一天。
Calendar c = Calendar.getInstance();
while (c.get(Calendar.DAY_OF_WEEK) != Calendar.MONDAY) {
c.add(Calendar.DATE, -1);
}
回答by Ant
The algorithm you're looking for (calculating the day of the week for any given date) is "Zeller's Congruence". Here's a Java implementation:
您正在寻找的算法（计算任何给定日期的星期几）是“Zeller's Congruence”。这是一个Java实现：
http://technojeeves.com/joomla/index.php/free/57-zellers-congruence
http://technojeeves.com/joomla/index.php/free/57-zellers-congruence
回答by Nivas
You can build up on this: The following code prints the first and last dates of each week for 15 weeks from now.
您可以以此为基础：以下代码打印从现在起 15 周内每周的第一个和最后一个日期。
Calendar c = Calendar.getInstance();
c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
for(int i=0; i<15; i++)
{
System.out.print("Start Date : " + c.getTime() + ", ");
c.add(Calendar.DAY_OF_WEEK, 6);
System.out.println("End Date : " + c.getTime());
c.add(Calendar.DAY_OF_WEEK, 1);
}
回答by Michael Piefel
Simply setting the day of week does not seem to be reliable. Consider the following simple code:
简单地设置星期几似乎并不可靠。考虑以下简单代码：
Calendar calendar = Calendar.getInstance(Locale.GERMANY);
calendar.set(2011, Calendar.SEPTEMBER, 18);
System.out.printf("Starting day: %tF%n", calendar);
calendar.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
System.out.printf("Last monday: %tF%n", calendar);
System.out.printf("First day of week: %d%n", calendar.getFirstDayOfWeek());
The result of running this program is:
运行这个程序的结果是：
Starting day: 2011-09-18
Last monday: 2011-09-19
First day of week: 2
In other words, it stepped forward in time. For a German locale, this is really not the expected answer. Note that the calendar correctly uses Monday as first day of the week (only for computing the week of the year, perhaps).
换句话说，它及时地向前迈进了一步。对于德国语言环境，这确实不是预期的答案。请注意，日历正确使用星期一作为一周的第一天（可能仅用于计算一年中的一周）。
回答by Gregor Koukkoullis
With the new date and time API in Java 8 you would do:
使用 Java 8 中的新日期和时间 API，您可以：
LocalDate now = LocalDate.now();
// determine country (Locale) specific first day of current week
DayOfWeek firstDayOfWeek = WeekFields.of(Locale.getDefault()).getFirstDayOfWeek();
LocalDate startOfCurrentWeek = now.with(TemporalAdjusters.previousOrSame(firstDayOfWeek));
// determine last day of current week
DayOfWeek lastDayOfWeek = firstDayOfWeek.plus(6); // or minus(1)
LocalDate endOfWeek = now.with(TemporalAdjusters.nextOrSame(lastDayOfWeek));
// Print the dates of the current week
LocalDate printDate = startOfCurrentWeek;
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("EEE dd/MM/yyyy");
for (int i=0; i < 7; i++) {
System.out.println(printDate.format(formatter));
printDate = printDate.plusDays(1);
}
回答by Przemek
Java.time
时间
Using java.timelibrary built into Java 8:
使用java.time内置于 Java 8 的库：
import java.time.DayOfWeek;
import java.time.LocalDate;
import static java.time.temporal.TemporalAdjusters.previousOrSame;
import static java.time.temporal.TemporalAdjusters.nextOrSame;
LocalDate now = LocalDate.now(); # 2015-11-23
LocalDate first = now.with(previousOrSame(DayOfWeek.MONDAY)); # 2015-11-23
LocalDate last = now.with(nextOrSame(DayOfWeek.SUNDAY)); # 2015-11-29
You can iterate over DayOfWeek.values()to get all current week days
您可以迭代DayOfWeek.values()以获取所有当前工作日
DayOfWeek.values(); # Array(MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY, SUNDAY)
for (DayOfWeek day: DayOfWeek.values()) {
System.out.print(first.with(nextOrSame(day)));
} # 2015-11-23, 2015-11-24, 2015-11-25, 2015-11-26, 2015-11-27, 2015-11-28, 2015-11-29
