package 正则;

 public class TestIsNum {

     public static void main(String[] args) {

         String s1="abc";

         String s2="987652345678009876543211234567890";

         String s3="a5678";

         String s4="23456789j";

         System.out.println(isNums(s1));

         System.out.println(isNums(s2));

         System.out.println(isNums(s3));

         System.out.println(isNums(s4));

         System.out.println(isNumsGoodMethod(s1));

         System.out.println(isNumsGoodMethod(s2));

         System.out.println(isNumsGoodMethod(s3));

         System.out.println(isNumsGoodMethod(s4));

     }

     public static boolean isNums(String arr){

         char[] charArray=arr.toCharArray();

         char[] nums={'0','1','2','3','4','5','6','7','8','9'};

         for(int i=0;i<charArray.length;i++){

             for(int j=0;j<nums.length;j++){

                 if(charArray[i]==nums[j]){

                     break;

                 }

                 if(j==nums.length-1){

                     return false;

                 }

             }

         }

         return true;

     }

     public static boolean isNumsGoodMethod(String arr){

         char[] charArray=arr.toCharArray();

         for(char c:charArray){

             if(c>'9'||c<'0')

                 return false;

         }

         return true;

     }

 }