The subexpression/metacharacter “re{ n, m}” matches at least n and at most m occurrences of the preceding expression.
Example 1
import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample { public static void main( String args[] ) { String regex = "xyy{2,4}"; String input = "xxyyzxxyyyyxyyzxxyyzz"; Pattern p = Pattern.compile(regex); Matcher m = p.matcher(input); int count = 0; while(m.find()) { count++; } System.out.println("Number of matches: "+count); } }
Output
Number of matches: 1
Example 2
The following Java program reads name value from the user and, it only allows 1 to 20 characters.
import java.util.Scanner; import java.util.regex.Matcher; import java.util.regex.Pattern; public class RegexExample { public static void main(String args[] ) { //Regular expression to match characters at least 1 almost 20 String regex = "[a-zA-Z]{1,20}"; Scanner sc = new Scanner(System.in); System.out.println("Enter students name:"); String name = sc.nextLine(); Pattern p = Pattern.compile(regex); Matcher m = p.matcher(name); if(m.matches()) { System.out.println("Name is appropriate"); } else { System.out.println("Name is inappropriate"); } } }
Output 1
Enter students name: Mouktika Name is appropriate
Output 2
Enter students name: ka 34 Name is inappropriate
Output 3
Enter students name: Sri Veera Venkata Satya Sai Suresh Santosh Samrat Name is in inappropriate