舍入时间（秒） [英] Round time by seconds

问题描述

在我的Java项目中，我想将日期时间秒数除以5。

In my Java project I want round Date time seconds which is divided by 5.

I have got   -   I want 
 12:00:01    -  12:00:00
 12:00:04    -  12:00:05
 12:00:06    -  12:00:05
 12:00:07    -  12:00:05
 12:00:08    -  12:00:10
 ...
 12:00:58    -  12:01:00

日期对象包含日期，例如： 2017年5月12日星期五12:00:03 CEST
，我想将秒数取模5。我想用舍入秒数实现Date对象。

Date object contain date for example: Fri May 12 12:00:03 CEST 2017 and I want round seconds to modulo 5. I want achieve Date object with rounded seconds.

如何使用简单的数学方法做到这一点或 Joda ？

How can I do this using simple math or Joda ?

推荐答案

以下是一个建议：

    LocalTime time = LocalTime.now(ZoneId.systemDefault()).truncatedTo(ChronoUnit.SECONDS);
    System.out.println("Before rounding: " + time);
    int secondsSinceLastWhole5 = time.getSecond() % 5;
    if (secondsSinceLastWhole5 >= 3) { // round up
        time = time.plusSeconds(5 - secondsSinceLastWhole5);
    } else { // round down
        time = time.minusSeconds(secondsSinceLastWhole5);
    }
    System.out.println("After rounding: " + time);

输出示例：

Before rounding: 14:46:33
After rounding: 14:46:35

Before rounding: 14:47:37
After rounding: 14:47:35

％5 （ 5）模的运算将为我们提供自时钟最后5秒以来的秒数，为0到4之间的一个数字。这样我们就知道舍入的方式。

The % 5 (modulo 5) operation will give us the number of seconds since the last whole 5 seconds on the clock, as a number in the interval 0 through 4. Using that we know which way to round.

我正在使用 java.time.LocalTime 。这是今天没有明确时区的推荐班级。

I am using java.time.LocalTime. It’s the recommended class for times without an explicit time zone today.

这篇关于舍入时间（秒）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！