public class Test {
     public static void main(String[] args) {
         Test test = new Test();
         System.out.println(test.lpad(10, 23));
     }

     /**
      * 补齐不足长度
      * @param length 长度
      * @param number 数字
      * @return
      */
     private String lpad(int length, int number) {
         String f = "%0" + length + "d";
         return String.format(f, number);
     }
 }