Java 日期年份计算按年份关闭两天 [英] Java Date year calculation is off by year for two days
问题描述
如果你能想象,这会在我的软件中导致一个 Y2K 风格的错误.奇怪的是,逐年计算只在一年中出现两天,我不太确定如何排除故障.
This caused a Y2K-style bug in my software if you can imagine. Strange thing is the off-by-one year calculation only occurs for two days in the year, which I'm less sure how to troubleshoot.
输出:
03-Jan-2013
02-Jan-2013
01-Jan-2013
31-Dec-2013 ** strange
30-Dec-2013 ** strange
29-Dec-2012
28-Dec-2012
27-Dec-2012
26-Dec-2012
25-Dec-2012
我不确定 Java 日期实用程序的哪一部分会导致此类错误.
I am not sure which part of the Java date utilities could cause such an error.
代码(由于测试很小,我包含了一个完整的工作程序):
The code (since the test is so small I included a complete working program):
import java.util.Calendar;
import java.util.Date;
import java.text.SimpleDateFormat;
public class DateT {
private static String getFormattedBackscanStartTime(int days) {
SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MMM-YYYY");
Calendar workingDate = Calendar.getInstance();
workingDate.add(Calendar.DATE, -1 * days);
String formattedStartTime = dateFormat.format(workingDate.getTime());
return formattedStartTime;
}
public static void main(String args[]) {
for(int i = 35; i < 45; i++) {
System.out.println(getFormattedBackscanStartTime(i));
}
}
}
推荐答案
这是问题所在:
"dd-MMM-YYYY"
YYYY
是周年,而不是日历年.你想要 yyyy
代替.
YYYY
is the week-year, not the calendar year. You want yyyy
instead.
2012 日历年的最后两天是 2013 年周的第一周.您通常只应将周年与一年中的周"说明符 (w
) 结合使用.
The last two days of calendar year 2012 were in the first week of week-year 2013. You should normally only use the week year in conjunction with the "week of year" specifier (w
).
这篇关于Java 日期年份计算按年份关闭两天的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!