如何查找最近过去的星期一？

Question

我正在使用 ColdFusion 9.0.1。

我每周一午夜都会举办一场比赛。我需要使用 ColdFusion（但我确信其他语言的逻辑是相同的）来查找最近星期一的日期。一旦确定了该日期，我就会将该日期放入 SQL 语句中以获取当前排名和过去的结果。

那么，我需要什么函数来查找最近过去的星期一呢？

回答

Dates = structNew();
Dates.CurrentDay = dateFormat(now(), "yyyy-mm-dd");
// LOOP MAX OF SEVEN TIMES
for (i = 1; i lte 7; i++) {
    // IF CURRENT DAY OF WEEK IS MONDAY SET AND BREAK
    if (dayOfWeek(Dates.CurrentDay) == 2) {
        Dates.BikeOfTheWeekDate = Dates.CurrentDay;
        break; 
    // IF CURRENT DAY OF WEEK IS NOT MONDAY SUBTRACT DAY
    } else {
        Dates.CurrentDay = dateAdd("d", -1, Dates.CurrentDay);
    }
}

Answer 1

您也可以从 2 中减去当前星期几（即星期一）

<!--- All days except Sunday (ie 2-Monday,...,7-Saturday) --->
<cfif dayOfWeek(currentDate) gt 1>
    <cfset mostRecentMonday = dateAdd("d", 2-dayOfWeek(currentDate), currentDate)>
<cfelse>
    <cfset mostRecentMonday = dateAdd("d", -6, currentDate)>
</cfif>

Answer 2

伪代码：

Get the current day
Loop
    Check if it's Monday
        If yes, break out of the loop
    Substract one
Next loop

在 ColdFusion 中，使用 DateAdd("d", -1, date) 减去一天，并使用 DayOfWeek(date) 检查周一，周一返回 2。

Answer 3

您还可以使用 java Calendar 类来完成此操作。

这是 ColdFusion 日期方法内部使用的。

<cfscript>
var cal = createObject( 'java', 'java.util.Calendar' ).getInstance();
cal.setTime( now() );

// if the (7) day of week is before (2) monday, we want the previous week
// decrement the (3) week of year
if ( cal.get(7) < 2 ) {
    cal.set( 3, cal.get(3) - 1 );
}

// set the (7) day of week back to (2) monday
cal.set( 7, 2 );    // 7 = day of week, 2 = monday

// reset time fields back to 0, aka midnight
cal.set( 11, 0 );   // 11 = hour of day
cal.set( 12, 0 );   // 12 = minute
cal.set( 13, 0 );   // 13 = second
cal.set( 14, 0 );   // 14 = millisecond

// get the last monday Date
var lastMonday = cal.getTime();

// cal.getTime() returns a java.util.Date
// if you want to convert the date to a ColdFusion OleDateTime, you can like so
var lastMonday = dateAdd( 'd', 0, cal.getTime() );

// or like this
var lastMonday = createObject( 'java', 'coldfusion.runtime.OleDateTime' ).init( cal.getTime() );
<cfscript>

http://docs.oracle.com/javase /1.5.0/docs/api/java/util/Calendar.html

http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Date.html