java - 如何创建一个 void 函数来列出 13 号下一个 13 星期五

Question

伙计们，我想创建一个 13 日即将到来的 13 个星期五的列表我该怎么做？

我尝试了一年:

  public static void getFridayThirteen() {

    for (int i = 1; i <= 365; i++) {
        if (Calendar.FRIDAY == 13) {
            fridayThirteen = i++;
            System.out.println("Test" + fridayThirteen);
        }
    }

但输出中没有出现任何内容。

Answer 1

执行此操作的一种方法是:

LocalDate ld = LocalDate.now(); // or the LocalDate.now(ZoneId) overload
int count = 0;
// first set the date to the next Friday first...
ld = ld.with(TemporalAdjusters.next(DayOfWeek.FRIDAY));
// this will find 10 such dates
while (count < 10) {
    if (isFriday13(ld)) { // implementation shown below
        count++;
        System.out.println(ld);
    }
    ld = ld.plusDays(7); // this set ld to be the next Friday
}

isFriday13 声明为:

private static boolean isFriday13(LocalDate ld) {
    return ld.getDayOfMonth() == 13 && ld.getDayOfWeek() == DayOfWeek.FRIDAY;
}