問題描述

我有方法根據時區查找月末日期.

I have method to find month end date based on the timezone.

Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("CET"));
calendar.set(
    Calendar.DAY_OF_MONTH, 
    calendar.getActualMaximum(Calendar.DAY_OF_MONTH)
);
System.out.println(calendar.getTime());`

它顯示輸出:Thu Aug 30 18:04:54 PDT 2018.

但是，它應該給我 CET 的輸出.

It should, however, give me an output in CET.

我錯過了什么?

推薦答案

Calendar.getTime() 方法返回一個 Date 對象，然后將其打印在代碼中.問題是 Date 類 不包含任何時區的概念，即使您使用 Calendar.getInstance() 指定了時區稱呼.是的，這確實令人困惑.

The Calendar.getTime() method returns a Date object, which you then printed in your code. The problem is that the Date class does not contain any notion of a timezone even though you had specified a timezone with the Calendar.getInstance() call. Yes, that is indeed confusing.

因此，為了在特定時區打印 Date 對象，您必須使用 SimpleDateFormat 類，打印前必須調用 SimpleDateFormat.setTimeZone() 指定時區.

Thus, in order to print a Date object in a specific timezone, you have to use the SimpleDateFormat class, where you must call SimpleDateFormat.setTimeZone() to specify the timezone before you print.

這是一個例子:

import java.util.Calendar;
import java.util.TimeZone;
import java.text.SimpleDateFormat;

public class TimeZoneTest {

    public static void main(String argv[]){
        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("CET"));
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
        System.out.println("calendar.getTime(): " + calendar.getTime());

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MMM-dd HH:mm:ss z");
        sdf.setTimeZone(TimeZone.getTimeZone("CET"));
        System.out.println("sdf.format(): " + sdf.format(calendar.getTime()));
     }
}

這是我電腦上的輸出:

calendar.getTime(): Fri Aug 31 01:40:17 UTC 2018
sdf.format(): 2018-Aug-31 03:40:17 CEST

這篇關于Java:根據時區計算月末日期的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！