在java中获取不同的时区

在java中，以毫秒为单位获取当前时间是有方法的，但这里需要系统时间。但是，假设我是印度时间和苏黎世时间，如何从我的系统中选择特定时区？

您必须更改系统日历中的时区，或者必须计算当前时区和所需时区之间的差异。然后将差异添加到当前时区。您将获得所需的时区时间。下面是一些你可以使用的方法

package com.jts1.service.timeconverter;

import android.annotation.SuppressLint;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

public class TimeConverterUtil {
private int offsetHours;
private int offsetMinutes;
private int selectedTimeZoneOffset;
private int currentTimeZoneoffset;
private int selectedtimeZoneOffsetMinutes;
private int dayLightSavings;
private long greenwichMeanTimeMilliSeconds;
private long localTimeMilliSeconds;
private String selectedTimeZoneType;
private String selectedTimeZoneName;
private String[] timeZoneIDs = TimeZone.getAvailableIDs();
private Calendar localCalendar;
private TimeZone selectedtimezone;
private TimeZone currentTimeZone;

@SuppressLint("SimpleDateFormat")
SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
        "EEEE, dd MMMM yyyy HH:mm:ss");

public int getSelectedTimeZoneOffset(int timeZoneTypePosition) {
    selectedTimeZoneType = timeZoneIDs[timeZoneTypePosition];
    selectedtimezone = TimeZone.getTimeZone(selectedTimeZoneType);
    selectedTimeZoneName = selectedtimezone.getDisplayName();
    selectedTimeZoneOffset = selectedtimezone.getRawOffset();
    if (selectedtimezone.inDaylightTime(new Date())) {
        dayLightSavings = selectedtimezone.getDSTSavings();
    }
    selectedTimeZoneOffset = selectedTimeZoneOffset - dayLightSavings;
    return selectedTimeZoneOffset;
}

public String getSelectedTimeZoneName(int timeZoneTypePosition) {
    selectedTimeZoneType = timeZoneIDs[timeZoneTypePosition];
    selectedtimezone = TimeZone.getTimeZone(selectedTimeZoneType);
    selectedTimeZoneName = selectedtimezone.getDisplayName();
    return selectedTimeZoneName;
}

public long getGreenwichMeanTime() {
    localCalendar = Calendar.getInstance();
    localTimeMilliSeconds = localCalendar.getTimeInMillis();
    currentTimeZone = Calendar.getInstance().getTimeZone();
    currentTimeZoneoffset = currentTimeZone.getRawOffset();
    if (currentTimeZone.inDaylightTime(new Date())) {
        currentTimeZoneoffset = currentTimeZoneoffset
                + currentTimeZone.getDSTSavings();
    }
    greenwichMeanTimeMilliSeconds = localTimeMilliSeconds
            - currentTimeZoneoffset;
    return greenwichMeanTimeMilliSeconds;
}

public int getOffsetHoursToGMT(int selectedTimeZoneOffset) {
    selectedtimeZoneOffsetMinutes = selectedTimeZoneOffset / (60 * 1000);
    offsetHours = selectedtimeZoneOffsetMinutes / 60;
    return offsetHours;
}

public int getOffsetMinutesToGMT(int selectedTimeZoneOffset) {
    selectedtimeZoneOffsetMinutes = selectedTimeZoneOffset / (60 * 1000);
    offsetMinutes = selectedtimeZoneOffsetMinutes % 60;
    return offsetMinutes;
}

}