定义IllegalScoreException异常类,代表分数相加后超出合理范围的异常。该异常是checked exception,即希望该异常一定要被捕获处理。

定义IllegalNameException异常类,代表名字设置不合理的异常。该异常是unchecked exception

定义Student类。

属性:

private String name;
private int score;

方法:

toString          //自动生成
setter/getter     //自动生成
改造setName       //如果姓名首字母为数字则抛出IllegalNameException
public int addScore(int score)  //如果加分后分数<0 或>100,则抛出IllegalScoreException,加分不成功。

main方法:

  1. 输入new则新建学生对象。然后输入一行学生数据,格式为姓名 年龄,接着调用setName,addScore。否则跳出循环。
  2. setName不成功则抛出异常,并打印异常信息,然后继续下一行的处理。
  3. addScore不成功则抛出异常,并打印异常信息,然后继续下一行的处理。如果2、3都成功,则打印学生信息(toString)
  4. 如果在解析学生数据行的时候发生其他异常,则打印异常信息,然后继续下一行的处理。
  5. Scanner也是一种资源,希望程序中不管有没有抛出异常,都要关闭。关闭后,使用System.out.println("scanner closed")打印关闭信息

注意: 使用System.out.println(e);打印异常信息,e为所产生的异常。

输入样例:

new
zhang 10
new
wang 101
new
wang30
new
3a 100
new
wang 50
other

输出样例:

Student [name=zhang, score=10]
IllegalScoreException: score out of range, score=101
java.util.NoSuchElementException
IllegalNameException: the first char of name must not be digit, name=3a
Student [name=wang, score=50]
scanner closed



答案

import java.util.Scanner;

class IllegalScoreException extends RuntimeException {
    String message;
    public IllegalScoreException() {
    }

    public IllegalScoreException(String message) {
        this.message = message;
    }

    @Override
    public String toString() {
        return "IllegalScoreException: score out of range, score=" + message;
    }
}

class IllegalNameException extends RuntimeException {
    String message;
    public IllegalNameException() {
    }

    public IllegalNameException(String message) {
        this.message = message;
    }

    @Override
    public String toString() {
        return "IllegalNameException: the first char of name must not be digit, name=" + message;
    }
}

class Student {
    private String name;
    private int score;

    public Student(){
        this.score = 0;
    }

    @Override
    public String toString() {
        return "Student [" +
                "name=" + name +
                ", score=" + score +
                ']';
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        if (name.charAt(0) >= '0' && name.charAt(0) <= '9'){
            throw new IllegalNameException(name);
        }
        this.name = name;
    }

    public int getScore() {
        return score;
    }

    public void setScore(int score) {
        this.score = score;
    }

    public int addScore(int score) throws IllegalScoreException{
        if (this.score + score < 0||this.score + score > 100){
            throw new IllegalScoreException(Integer.toString(this.score + score));
        }
        setScore(this.score + score);
        return this.score;
    }
}

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()){
            String str = scanner.next();
            if (!str.equals("new")){
                scanner.close();
                System.out.println("scanner closed");
                break;
            }
            Student stu = new Student();
            scanner.nextLine();
            String nameAndScore = scanner.nextLine();
            String[] arr = nameAndScore.split("\\s+");
            try{
                String name = arr[0];
                int score = Integer.parseInt(arr[1]);
                stu.setName(name);
                stu.addScore(score);
                System.out.println(stu);
            }catch (IllegalNameException | IllegalScoreException e){
                System.out.println(e);
            }catch (Exception e){
                System.out.println("java.util.NoSuchElementException");
            }
        }
    }
}
最后修改:2020 年 10 月 13 日 06 : 53 PM
愿君多打钱,此物最相思