Java 异常练习

1 public class NumException extends Exception{
2     //创建Exception的子类，NumException 用于作为该作业的异常类型
3     public NumException(String message) {
4         super(message);
5         System.err.println("数据输入错误");
6     }
7 }

 1 public class Work1Test {
 2     static Scanner sc = new Scanner(System.in);
 3     public static void main(String[] args) {
 4         Work1 work1 = new Work1();
 5         System.out.println("请输入1-3，查看对应课程");
 6         try {
 7             System.out.println(work1.choose(sc.nextInt()));
 8         } catch (Exception e) {
 9             System.err.println(e.getMessage());
10         }finally {
11             System.out.println("欢迎提出建议");
12         }
13     }
14 }

 1 public class Work1 {
 2     public String choose(int num) throws NumException {
 3         String keCheng = "";
 4         if (num < 1 || num > 3) {
 5             throw new NumException("输入非法，你不用来上课了");
 6         }
 7         switch (num) {
 8             case 1:
 9                 keCheng = "Java 课";
10                 break;
11             case 2:
12                 keCheng = "音乐课";
13                 break;
14             case 3:
15                 keCheng = "C#课";
16                 break;
17         }
18         return keCheng;
19     }
20 }