Compare 2 Dates , Convert String into Date , Convert Date into String - in java SimpleDateFormat

Here i m discuss SimpleDateFormat class SimpleDateFormat is a concrete class for formatting and parsing dates in a locale-sensitive manner. It allows for formatting (date -> String), parsing (String -> date). It allows you to choosing any user-defined date-time formatting patterns.

Letter	Date or Time Component	Presentation	Examples
G	Era designator	Text	AD
y	Year	Year	1996; 96
M	Month in year	Month	July; Jul; 07
w	Week in year	Number	27
W	Week in month	Number	2
D	Day in year	Number	189
d	Day in month	Number	10
F	Day of week in month	Number	2
E	Day in week	Text	Tuesday; Tue
a	Am/pm marker	Text	PM
H	Hour in day (0-23)	Number	0
k	Hour in day (1-24)	Number	24
K	Hour in am/pm (0-11)	Number	0
h	Hour in am/pm (1-12)	Number	12
m	Minute in hour	Number	30
s	Second in minute	Number	55
S	Millisecond	Number	978
z	Time zone	General time zone	Pacific Standard Time; PST; GMT-08:00
Z	Time zone	RFC 822 time zone	-0800

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public class SimpleDateFormat extends DateFormat

SimpleDateFormatPattern .Java Sample Code

public static void main(String[] args) throws ParseException {

  SimpleDateFormat format = null;
  String startDate = "2013-01-08 12:10:56";
  String endDate = "2013-12-09 10:10:56";
  
  System.out.println("<<<<<<<<<<<<<<--------Compare 2 Dates------------>>>>>>>>>>>>>>>>>>>>"); 
  new SimpleDateFormatPattern().compareTwoDate( format , startDate , endDate);
  
         System.out.println("<<<<<<<<<<<<<<--------Convert String into Date------->>>>>>>>>>>>>>>>>"); 
  new SimpleDateFormatPattern().convertStringToDate(format , startDate , endDate);
  
         System.out.println("<<<<<<<<<<<<<<--------Convert Date into String------>>>>>>>>>>>>>>>>>>"); 
         new SimpleDateFormatPattern().convertDateToString(format);
 }

Compare 2 Dates

private void compareTwoDate(SimpleDateFormat format, String startDate, String endDate) {
  Date date1 , date2;
  format = new SimpleDateFormat("yyyy-MM-dd");
  try {
   date1 = format.parse(startDate);
   date2 = format.parse(endDate);
   
   if (date1.compareTo(date2) < 0) 
    System.out.println("Start Date is before than End Date");
   
   else if(date1.compareTo(date2) >0)
    System.out.println("Start Date is after than End Date");
   
   else
    System.out.println("Start Date and End Date both are equal");
  } catch (ParseException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

Convert String into Date

private void convertStringToDate(SimpleDateFormat format, String startDate, String endDate) {
  format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
  try {
   Date startDates =  format.parse(startDate);
   Date endDates = format.parse(endDate);
   
   System.out.println("String to date    :"+startDates);
   System.out.println("String to date    :"+endDates);
   
  } catch (ParseException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

Convert Date into String

private void convertDateToString(SimpleDateFormat format) {
  format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss"); 
   Date date = new Date();
   String todayDate = format.format(date);
   System.out.println("Date to String    :" +todayDate);
 }

after executing SimpleDateFormatPattern.java following result shown :-