how to convert Date(2019/5/10) to shamsiDate(1398/4/12) - web-services

Question

I had called a web service in my code that contains Deadline Date . the problem is the response in swagger shows like this :
{
"id": "289",
"serviceName": "خدمت 1",
"deadLine": "2024/05/06",
...
...
}
and I want to show deadline in Shamsi Date like 1398/4/12.
i have used a lot of convertors but it did not worked for me and still shows the "deadLine": "2024/05/06",
this is my view :
public String setDeadLine(Date deadLine) {
this.deadLine = deadLine;
String dateFa;
//String dateFa= DateConvertor.miladi2date(deadLine);
dateFa= this.ConvertToPersianToShow(deadLine);
return dateFa;
}
public String ConvertToPersianToShow(Date deadLine)
{
CalendarTool cl = new CalendarTool();
String date;
String year = cl.getIranianYearInCentury();
String Month = cl.getIranianMonthStr();
String day = cl.getIranianWeekDayStr();
date = year+"/" + Month + "/" + day;
return date;
}
should I type any code in my controller ?

Answer 1

RESOLVE :
I just need to add some code in ConvertToPersianToShow :
calendarTool should be filled .mine was empty
I added this code :
String[] date = deadLine.split("/");
if(date.length != 3)
return null;
Calendar calendar = GregorianCalendar.getInstance();
calendar.set(Integer.parseInt(date[0]),Integer.parseInt(date[1]),Integer.parseInt(date[2]));
and filled the calendar :
CalendarTool cl = new CalendarTool(calendar);