import java.util.InputMismatchException;
import java.util.Scanner;public class LianXi {public static void main(String[] args) {Scanner input = new Scanner(System.in);System.out.println("请输入1~3中的任意数字，将会显示相应的课程内容：");int num = 0;try {num = input.nextInt();switch (num){case 1:System.out.println("数学课！");break;case 2:System.out.println("语文课！");break;case 3:System.out.println("英语课！");break;default:System.out.println("输入的数字有误！");break;}}catch (InputMismatchException e){System.err.println("输入错误！");e.printStackTrace();System.out.println(e.getMessage());}catch (Exception e){System.err.println("输入错误！");}finally{System.out.println("欢迎提出建议！");}}
}

请输入1~3中的任意数字，将会显示相应的课程内容：
b
输入错误！
java.util.InputMismatchExceptionat java.util.Scanner.throwFor(Scanner.java:864)at java.util.Scanner.next(Scanner.java:1485)at java.util.Scanner.nextInt(Scanner.java:2117)at java.util.Scanner.nextInt(Scanner.java:2076)at LianXi.main(LianXi.java:12)
null
欢迎提出建议！

package com.yichang.zuoye;public class Person {private String name;private String sex;private int age;public Person() {}public Person(String name, String sex, int age) {this.name = name;this.sex = sex;this.age = age;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getSex() {return sex;}public void setSex(String sex)throws Exception {if(sex.equals("男")||sex.equals("女")){this.sex = sex;}else{throw new Exception("性别只可以是男或者女！");}}public int getAge() {return age;}public void setAge(int age) throws Exception {if(age>=1&&age<=100){this.age = age;}else{throw new Exception("年龄必须在1到100之间！");}}public void showInfo(){System.out.println("本人叫"+this.getName()+"，性别："+this.getSex()+"，年龄为："+this.getAge());}
}

package com.yichang.zuoye;public class TestPerson {public static void main(String[] args) {Person p = new Person();try{p.setAge(101);}catch (Exception e){e.printStackTrace();}}}

java.lang.Exception: 年龄必须在1到100之间！at com.yichang.zuoye.Person.setAge(Person.java:46)at com.yichang.zuoye.TestPerson.main(TestPerson.java:7)Process finished with exit code 0