Java检查字符串是否包含数字

public class ContainsExample {

   public static void main(String args[]){

      String sample = "krishna64";

      char[] chars = sample.toCharArray();

      StringBuilder sb = new StringBuilder();

      for(char c : chars){

         if(Character.isDigit(c)){

            sb.append(c);

         }

      }

      System.out.println(sb);

   }

}