package hello;
//自定义异常
class  MathException extends Exception{
    MathException(){
        System.out.println("输入的格式不正确！");
                }
}
public class Hello{
     
    public static void input(String t) throws MathException //抛出异常选项
    {
        int i;
        char[]stringArr=t.toCharArray();                //将自字符串放进数组
        for(i=0;i<t.length();i++) {                     //通过数组遍历，检验字符串是否由纯数组组成
            if(stringArr[i]<49||stringArr[i]>57) {
                throw new MathException();      //抛出异常
            }
        }
        System.out.println(String.valueOf(t));
    }
     
     
     
    public static void main(String args[]) {
      try {
        String t=new String("123123");
        input(t);
        
      }
      catch(MathException e) {
          System.out.println(e);
      }
      finally {
          System.out.println("程序运行结束！");
      }
    }
 }```