問(wèn)題描述

我有一堂課電影其中我有一個(gè)開(kāi)始日期、一個(gè)持續(xù)時(shí)間和一個(gè)停止日期.開(kāi)始和停止日期是日期對(duì)象(私有日期 startDate ...)(這是一個(gè)任務(wù)，所以我不能改變它)現(xiàn)在我想通過(guò)將持續(xù)時(shí)間(以分鐘為單位)添加到 startDate 來(lái)自動(dòng)計(jì)算 stopDate.

I have a class Movie in it i have a start Date, a duration and a stop Date. Start and stop Date are Date Objects (private Date startDate ...) (It's an assignment so i cant change that) now I want to automatically calculate the stopDate by adding the duration (in min) to the startDate.

據(jù)我所知，不推薦使用 Date 的時(shí)間操縱功能，因此這是不好的做法，但另一方面，我看不到將 Date 對(duì)象轉(zhuǎn)換為日歷對(duì)象以操縱時(shí)間并將其重新轉(zhuǎn)換為 Date 對(duì)象的方法.有辦法嗎?如果有什么是最佳做法

By my knowledge working with the time manipulating functions of Date is deprecated hence bad practice but on the other side i see no way to convert the Date object to a calendar object in order to manipulate the time and reconvert it to a Date object. Is there a way? And if there is what would be best practice

推薦答案

你可以做的是創(chuàng)建一個(gè) GregorianCalendar 的實(shí)例，然后將 Date 設(shè)置為開(kāi)始時(shí)間:

What you could do is creating an instance of a GregorianCalendar and then set the Date as a start time:

Date date;
Calendar myCal = new GregorianCalendar();
myCal.setTime(date);

但是，另一種方法是根本不使用 Date.您可以使用這樣的方法:

However, another approach is to not use Date at all. You could use an approach like this:

private Calendar startTime;
private long duration;
private long startNanos;   //Nano-second precision, could be less precise
...
this.startTime = Calendar.getInstance();
this.duration = 0;
this.startNanos = System.nanoTime();

public void setEndTime() {
        this.duration = System.nanoTime() - this.startNanos;
}

public Calendar getStartTime() {
        return this.startTime;
}

public long getDuration() {
        return this.duration;
}

通過(guò)這種方式，您可以訪問(wèn)開(kāi)始時(shí)間并獲取從開(kāi)始到停止的持續(xù)時(shí)間.當(dāng)然，精度取決于您.

In this way you can access both the start time and get the duration from start to stop. The precision is up to you of course.

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