java - JS/Java 任何城市的夏令时时间

Question

我想要一个可以按以下方式工作的代码。
显示需要自动处理夏令时的8-10个城市的时间。

For example : Melbourne observes DST, a API using which I can fetch the current time based on location without any hardcode done for DST calculation.

目前正在运行的代码基于硬编码值。它选择系统时间转换为 GMT，然后根据位置添加/减去偏移量。

然后根据日期计算夏令时并适当添加。

但是我想使用一些 API 来删除硬编码值，我正在尝试使用下面的代码。

The below code giving time for IST/GMT, but when I put AEST/AEDT it doesnt give the correct time.


public class DateFormatter {

    public static String formatDateToString(Date date, String format,
            String timeZone) {
        // null check
        if (date == null) return null;
        // create SimpleDateFormat object with input format
        SimpleDateFormat sdf = new SimpleDateFormat(format);
        // default system timezone if passed null or empty
        if (timeZone == null || "".equalsIgnoreCase(timeZone.trim())) {
            timeZone = Calendar.getInstance().getTimeZone().getID();
        }
        // set timezone to SimpleDateFormat
        sdf.setTimeZone(TimeZone.getTimeZone(timeZone));
        // return Date in required format with timezone as String
        return sdf.format(date);
    }

    public static void main(String[] args) {
        //Test formatDateToString method
        Date date = new Date();
        System.out.println("Default Date:"+date.toString());
        System.out.println("System Date: "+formatDateToString(date, "dd MMM yyyy hh:mm:ss a", null));
        System.out.println("System Date in PST: "+formatDateToString(date, "dd MMM yyyy hh:mm:ss a", "PST"));
        System.out.println("System Date in IST: "+formatDateToString(date, "dd MMM yyyy hh:mm:ss a", "IST"));
        System.out.println("System Date in GMT: "+formatDateToString(date, "dd MMM yyyy hh:mm:ss a", "GMT"));
        System.out.println("System Date in CT: "+formatDateToString(date, "dd MMM yyyy hh:mm:ss a", "BDT"));
    }

}

Answer 1

import java.time.LocalTime;
import java.time.ZoneId;

public class Main {
  public static void main(String... args) {
        ZoneId zone2 = ZoneId.of("America/Santiago");
     LocalTime now2 = LocalTime.now(zone2);
    System.out.println(now2);
  }
}

Use the below link to know the timezones

http://joda-time.sourceforge.net/timezones.html