2.21

package com.yichang;

import java.util.Scanner;

//年龄类
public class Age {
    int age;
    
    public int getInt() {
        return age;
    }
    public void setInt (int age) throws Exception {
        if(age<=100 && age>=1) {
            this.age = age;
        }else {
            throw new Exception("年龄不能小于1或者大于100");
        }
    }
    public void print() {
        System.out.println("这个人的年龄是"+this.age);
    }
    //测试
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        Age a = new Age();
        try {
            System.out.println("请输入年龄：");
            int age = input.nextInt();
            a.setInt(age);
            a.print();
        }catch(Exception e) {
            e.printStackTrace();
            System.err.println("不能出现非数字的字符");
        }
        System.out.println("感谢使用本程序！");
    }
}

package com.yichang;

import java.util.Scanner;

//try catch finally 练习
public class Test1 {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("请输入课程代号（1~3之间的数字）：");
        int choose = 0;
        try {
            choose = input.nextInt();
            switch(choose) {
            case 1:
                System.out.println("语文");
                break;
            case 2:
                System.out.println("数学");
                break;
            case 3:
                System.out.println("英语");
                break;
            }
        }catch(Exception e){
            System.err.println("不能输入1~3外的字符");
        }finally {
            System.out.println("欢迎使用");
        }
            System.out.println("sssss");
        
    }
}