public static String leadingZeros(int value, int returnSize){
int size = (int) Math.log10(value)+1;
if (size > returnSize){
return String.valueOf(value).substring(size-returnSize);
}
StringBuilder string = new StringBuilder();
for (int i=returnSize; i>size;i--){
string.append("0");
}
string.append(value);
return string.toString();
}
Пример:
System.out.println(leadingZeros(123,5));
--> 00123
System.out.println(leadingZeros(123456789,5));
--> 56789