Converting Date with Time in PST into UTC format

问题

i am having a variable str(string type)having "28-Nov-2013 09:15 AM" as its value.How to convert it into UTC format(the above mentioned time in str variable is in PST, hence UTC should be 8 hours more than that).I am using flex 2.Find below is following code which is not working:-

 txtDate.text= formatDateUTC(txtDate.text); //here txtDate.text=28-Nov-2013 09:15 AM

    private function formatDateUTC(originalDate:String):String
    {
        Alert.show('original '+originalDate);
        var dtValue:Date = new Date(Date.parse(originalDate.replace("-"," ")));
        var editedDate:String=pstFormatter.format(dtValue);
        Alert.show('edited '+editedDate);


        return (dateFormatter.format(dateAdd("hours",8,dtValue))).toString();

    }
    private function dateAdd(datepart:String = "", number:Number = 0, date:Date = null):Date
            {
        if (date == null) {
            date = new Date();
        }

        var returnDate:Date = new Date(date);;

        switch (datepart.toLowerCase()) {
            case "fullyear":
            case "month":
            case "date":
            case "hours":
            case "minutes":
            case "seconds":
            case "milliseconds":
                returnDate[datepart] += number;
                break;
            default:
                /* Unknown date part, do nothing. */
                break;
        }
       return returnDate;
    }

回答1:

Wise programmers leave the heavy-lifting of date-time calculations to a specialized library. In Java, that would be Joda-Time (or in Java 8, JSR 310).

Here is example code for Joda-Time 2.3 in Java 7.

// © 2013 Basil Bourque. This source code may be used freely forever by anyone taking full responsibility for doing so.

String dateString = "28-Nov-2013 09:15 AM"; // Assumed to be the local date-time in United States west coast.
//String dateString = "28-Nov-2013 09:15 PM";  // Test "PM" as well as "AM" if you like.

// Joda-Time has deprecated use of 3-letter time zone codes because of their inconsistency. Use other identifier for zone.
// Time Zone list: http://joda-time.sourceforge.net/timezones.html
org.joda.time.DateTimeZone californiaTimeZone = org.joda.time.DateTimeZone.forID( "America/Los_Angeles" );

// Joda-Time formatting codes: http://www.joda.org/joda-time/key_format.html
org.joda.time.format.DateTimeFormatter dateStringFormat = org.joda.time.format.DateTimeFormat.forPattern( "dd-MMM-yyyy hh:mm aa" ).withZone( californiaTimeZone );

org.joda.time.DateTime californiaDateTime = dateStringFormat.parseDateTime( dateString );
org.joda.time.DateTime utcDateTime = californiaDateTime.toDateTime( org.joda.time.DateTimeZone.UTC );

// Both of these date-time objects represent the same moment in the time-line of the Universe, 
// but presented with different time-zone offsets.
System.out.println( "californiaDateTime: " + californiaDateTime );
System.out.println( "utcDateTime: " + utcDateTime );

When run…

californiaDateTime: 2013-11-28T09:15:00.000-08:00
utcDateTime: 2013-11-28T17:15:00.000Z

来源：https://stackoverflow.com/questions/20144791/converting-date-with-time-in-pst-into-utc-format