20190221课堂作业<异常>

public class Test01 {
    public static void main(String[] args) {
        System.out.println("请输入1~3之间任一数字:");
        Scanner in = new Scanner(System.in);
        try {
            int num = in.nextInt();
            switch (num) {
            case 1:
                System.out.println("C#编程");
                break;
            case 2:
                System.out.println("JAVA编程");
                break;
            case 3:
                System.out.println("编程专业英语");
                break;
            }
        } catch (Exception e) {
            System.out.println("输入值不是数字");
            e.printStackTrace();
        } finally {
            System.out.println("欢迎提出建议!");
        }
    }
}

请输入1~3之间任一数字:
d
输入值不是数字
java.util.InputMismatchException
    at java.util.Scanner.throwFor(Scanner.java:909)
    at java.util.Scanner.next(Scanner.java:1530)
    at java.util.Scanner.nextInt(Scanner.java:2160)
    at java.util.Scanner.nextInt(Scanner.java:2119)
    at Test2019.M02.d19.Test01.main(Test01.java:10)
欢迎提出建议!

 定义报错的类:AgeException

public class AgeException{
    private int 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!");
        }
    }
}

测试:

public class Test02 {

    public static void main(String[] args) {
        AgeException person = new AgeException();
        try {
            person.setAge(120);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

java.lang.Exception: 年龄必须在1到100之间!
    at Test2019.M02.d19.AgeException.setAge(AgeException.java:12)
    at Test2019.M02.d19.Test02.main(Test02.java:8)

自己定义异常

public class GenderException extends Exception{
    //好处:可以通过异常名字,清晰知道异常原因,以及针对处理
    //无参构造方法
    public GenderException() {
        super();
    }
    //有参构造方法,只有继承Exception的构造方法,才能在控制台输出,错误信息
    public GenderException(String message) {
        super(message);
    }

public class GenderDamo {
    private String sex;

    public void setSex(String sex)throws GenderException{
        if(sex == "男"){
            System.out.println("他是男生!");
        }else if (sex == "女"){
            System.out.println("她是女生!");
        }else{
            throw new GenderException("必须输入:男or女");
        }
    }
    public static void main(String[] args) {
        GenderDamo person = new GenderDamo();
        try {
            person.setSex("Gay");
        } catch (GenderException e) {
            e.printStackTrace();
        }
    }
}