Convert different Date Formats into Date based on User locale

Question

I am getting different formats of date formats in date field from Json as a string.

I should be able to convert any Date format into Date based on user locale.below are the example of formats.

Ex:

1. "date": "2018-12-10T10:03:00.116Z"
2. "date": "Mon Sep 17 10:35:28 2018"

I implemented below code to convert it.

string Dt = (string)sysdet.get('date');                          //getting string values of date from json content in msg field                  
if(Dt.contains('T'))
    //if(String.isNotBlank(Dt) &&  
    //Pattern.matches('\\d\\d\\d\\d-\\d\\d-\\d\\d \\d\\d:\\d\\d:\\d\\d', Dt))
{
    String[] str = dt.split('T');                    
    String JDate =string.valueof(str[0]);
    /*  string[] dts=JDate.split('-');
string dd=string.valueof(dts[2]);
string mm=string.valueof(dts[1]);      
string yyyy=string.valueof(dts[0]);
string finaldate=mm+'/'+ dd+'/'+ yyyy ;      */       
    Date parsedate= Date.valueof(JDate); 
    date datval=system.today();
    DateTime dtNow =parsedate; 
    String formattedDate = dtNow .format('yyyy-MM-dd',  UserInfo.getTimeZone().toString());
    system.debug('formattedDate2:::' +formattedDate );
    //date dateval=system.today();
    Licensedate=date.valueof(formattedDate );
    system.debug('Licensedate::'+Licensedate);  
    system.debug('parsedate::'+parsedate);  
    system.debug('str::'+str);               
    // system.debug('finaldate::'+finaldate);
    system.debug('JDate::'+JDate);
}
else
{
    Licensedate=null;
}
if( Licensedate !=null)
{ 
    DateTime dtValue = DateTime.newInstance(Licensedate.year(), Licensedate.month(), Licensedate.day());
    FormattedDate = dtValue.format('dd-MMM-yyyy');                                              
    system.debug('FormattedDate ::'+FormattedDate );
}

Is there any method that convert string of any date format to standard format of date?

Answer 1

Salesforce does not provide services to parse arbitrary inbound date-time formats. (Note that the values you're quoting are date-times, not dates).

You can parse these values in a number of ways, but there's no single method that accepts a date-time and a format string against which to parse it.

JSON Deserialization

DateTime incomingDateTime = JSON.deserialize('"2018-10-01T00:00:00Z"', DateTime.class);

This approach can handle ISO-format dates, as shown above. Note the extra set of double quotes, which make it into a JSON value for the parser's purposes.

This is applicable to your first example,

"date": "2018-12-10T10:03:00.116Z"

Because this date-time format is both comprehensive and well-standardized, it's preferable to use it wherever possible.

DateTime.valueOf() and Date.valueOf()

DateTime.valueOf() and Date.valueOf accept a string in a standard format similar to but not quite identical to that handled by the JSON parser:

The specified string should use the standard date format “yyyy-MM-dd HH:mm:ss” in the local time zone.

Note that it uses the local time zone, where the value above specifies "Z" for GMT.

DateTime.parse()

DateTime.parse()

Constructs a Datetime from the given String in the local time zone and in the format of the user locale.

This method is best used for processing user input (if at all), because it's tied to the local time zone and the locale of the running user (not the organization). You can't specify a locale for parsing.

Manual Parsing

As you've started to do in your code, you can implement parsers for other non-standard date and time formats yourself. The logic for these is usually pretty straightforward (using split() and possibly some regexes) but you'll have to be careful to make sure you handle time zones appropriately.

Converting DateTime to Date

You can call the date() and dateGMT() methods on any DateTime value to get its associated Date. You must be aware of time zones, though: Date-Time values have a time zone, and Dates do not. The time zone in which the Date-Time is interpreted at the time of conversion can affect what Date is returned.

Answer 2

Use method for that:

format()

Returns the Date as a string using the locale of the context user

Here are what those formats would look like:

// In American-English locale
date myDate = date.newInstance(2001, 3, 21);
String dayString = myDate.format();
system.assertEquals('3/21/2001', dayString);