Java Examples - Check Date Format


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Problem Description

How to check check whether date is in proper format or not?

Solution

Following example demonstrates how to check whether the date is in a proper format or not using matches method of String class.

public class Main {
   public static void main(String[] argv) {
      boolean isDate = false;
      String date1 = "8-05-1988";
      String date2 = "08/04/1987";
      String datePattern = "\\d{1,2}-\\d{1,2}-\\d{4}";
      
      isDate = date1.matches(datePattern);
      System.out.println("Date :"+ date1+": matches with the this date Pattern:"+datePattern+"Ans:"+isDate);
      
      isDate = date2.matches(datePattern);
      System.out.println("Date :"+ date2+": matches with the this date Pattern:"+datePattern+"Ans:"+isDate);
   }
}

Result

The above code sample will produce the following result.

Date :8-05-1988: matches with the this date Pattern: \d{1,2}-\d{1,2}-\d{4}Ans:true
Date :08/04/1987: matches with the this date Pattern: \d{1,2}-\d{1,2}-\d{4}Ans:false

The following is an example to check check whether date is in proper format or not.

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Main {
   public static void main(String args[]) {
      List dates = new ArrayList();
      dates.add("25/12/1990");
      dates.add("25/12/1990");
      dates.add("12/12/90");
      dates.add("05/02/1990");
      String regex = "^(1[0-2]|0[1-9])/(3[01]|[12][0-9]|0[1-9])/[0-9]{4}$";
      Pattern pattern = Pattern.compile(regex);
      
      for(Object date : dates) { 
         Matcher matcher = pattern.matcher((CharSequence) date);
         System.out.println(date +" : "+ matcher.matches());
      }
   }
}

Result

The above code sample will produce the following result.

25/12/1990 : false
25/12/1990 : false
12/12/90 : false
05/02/1990 : true

java_regular_exp.htm

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