Java：异常处理除数问题

问题：异常处理两个数做除法时的异常问题！

代码：

package Demo1;
import java.util.*;
public class Demo1 {
public static void main(String[] args) {
	Scanner input = new Scanner(System.in);
	try {
		System.out.print("please input a number:");
		int a = input.nextInt();
		System.out.print("please input a number:");
		int b = input.nextInt();
		sub(a,b);
	}
	catch(InputMismatchException e) {
		System.out.println("出错"+e.toString());
//			System.out.println("出错"+e.getMessage());
//			e.printStackTrace();
	}
	catch(Exception e) {
		System.out.println("出错"+e.toString());
//			System.out.println("出错"+e.getMessage());
//			e.printStackTrace();
	}
	finally {
		System.out.println("程序运行结束");
	}
}
public static void sub(int a1 , int a2) {
	if(a2 == 0) {
		throw new ArithmeticException("运算时异常");
	}else {
		System.out.print("两个数的商为："+a1/a2);
	}
}

}