1)次setCalendarのような方法を使用できますNSDateFormatter :
NSCalendar *hebrew = [[NSCalendar alloc] initWithCalendarIdentifier:NSHebrewCalendar];
[dateFormat setCalendar:hebrew ];
2)また、次を使用できます:
NSCalendar * gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSCalendar * hebrew = [[NSCalendar alloc] initWithCalendarIdentifier:NSHebrewCalendar];
NSDate *date = [NSDate date];
NSDateComponents *components = [gregorian components:NSUIntegerMax fromDate:date];
NSDate *hebrewDate = [hebrew dateFromComponents:components];