如何将日历日期限制为 10 分钟？

问题描述

有一种更好的方法可以将日期时间四舍五入（天花板和地板）以下代码的十分钟：

public void hintOfTime() {
        Date orario = new SimpleDateFormat("hh:mm").parse(usaServizio_standard.setstr());
        // I have skipped the try catch for an easy read
        Calendar calendar = GregorianCalendar.getInstance();
        calendar.setTime(orario);
        int minutes = calendar.get(Calendar.MINUTE);
        if(minutes>=1 && minutes<=9) {
            usaServizio_standard.hint("not valid date","Try with: "+ calendar.get(Calendar.HOUR+1)+":00 or "+calendar.get(Calendar.HOUR+1)+":10");
        }else if(minutes>=11 && minutes<=19) {
            usaServizio_standard.hint("not valid date","Try with: "+ calendar.get(Calendar.HOUR+1)+":10 or "+calendar.get(Calendar.HOUR+1)+":20");
        }else if(minutes>=21 && minutes<=29) {
            usaServizio_standard.hint("not valid date","Try with: "+ calendar.get(Calendar.HOUR+1)+":20 or "+calendar.get(Calendar.HOUR+1)+":30");
        }else if(minutes>=31 && minutes<=39) {
            usaServizio_standard.consiglio("not valid date","Try with: "+ calendar.get(Calendar.HOUR+1)+":30 or "+calendar.get(Calendar.HOUR+1)+":40");
        }else if(minutes>=41 && minutes<=49) {
            usaServizio_standard.consiglio("not valid date","Try with "+ calendar.get(Calendar.HOUR+1)+":40 or "+calendar.get(Calendar.HOUR+1)+":50");
        }else {
            usaServizio_standard.hint("not valid date","Try with"+ calendar.get(Calendar.HOUR+1)+":50 or "+calendar.get(Calendar.HOUR+2)+":00");
        }
    }

这个解决方案工作正常，但太丑了。我不知道做同样的工作是否有更好更简短的解决方案。

解决方法

java.time

我建议您使用 java.time，现代 Java 日期和时间 API，用于您的时间工作。

    String timeString = "09:56";
    
    LocalTime time = LocalTime.parse(timeString);
    int minute = time.getMinute();
    if (minute % 10 != 0) {
        // truncate to whole 10 minutes
        LocalTime firstSuggestedTime = time.withMinute(minute / 10 * 10);
        LocalTime secondSuggestedTime = firstSuggestedTime.plusMinutes(10);
        System.out.format("Not a valid time; try with %s or %s.%n",firstSuggestedTime,secondSuggestedTime);
    }

这个例子的输出是：

无效时间；尝试 09:50 或 10:00。

链接

Oracle tutorial: Date Time 解释如何使用 java.time。