异常的捕获与处理（复习）

package com.main;

import java.util.Scanner;

class MyException extends Exception {
    public MyException(String s) {
        super(s);
    }
}

class Math {
    float div(float a, float b) throws MyException {
        if (a < 0 || b < 0) {
            try {
                throw new MyException("输入的数为负数！");
            }
            catch(MyException e) {
                throw e;
            }
            finally {
                System.out.println("输入结束.");
            }
        }

        if (b == 0) {
            try {
                throw new MyException("除数为零.");
            }
            catch(MyException e) {
                throw e;
            }
            finally {
                System.out.println("输入结束.");
            }
        }
        return a / b;
    }
}

class Text {
    public static void main(String[] args) {
        Math m = new Math();
        Scanner s = new Scanner(System.in);

        System.out.println("两个数的除法（大于零）：");
        while (s.hasNextFloat()) {
            float a, b;
            a = s.nextFloat();
            b = s.nextFloat();
            try {
                System.out.println(m.div(a, b));
            }
            catch(Exception e) {
                System.out.println(e);
                System.out.println();
            }
        }
    }
}