（1）通过继承Exception异常类，创建一个自定义异常类MyException。 （2）再创建一个Student类，包含：学生姓名String name；四科成绩double[] score；学生总成绩double sum() throws MyException, 如果某一科成绩为负，则抛出一个MyException异常，具体信息为：“成绩不能为负”；显示学生的信息void display（）throws MyException，如果某一科成绩为负，则抛出一个MyException异常，具体信息为：“成绩不能为负”。 （3）创建一个主类，在main函数中创建学生对象，在键盘输入其各个成员的信息。并显示该学生的详细信息及总成绩。2种写法

第一种写法：

MyException.java

public class MyException extends Exception {
    public MyException(String message) {
        super(message);
    }
}

Student.java

import java.util.Scanner;

public class Student {
    private String name;
    private double[] score;

    public Student() {
        Scanner scanner = new Scanner(System.in);

        System.out.print("请输入学生姓名：");
        name = scanner.nextLine();

        score = new double[4];
        for (int i = 0; i < score.length; i++) {
            System.out.print("请输入第" + (i + 1) + "科成绩：");
            score[i] = scanner.nextDouble();

            if (score[i] < 0) {
                try {
                    throw new MyException("成绩不能为负");
                } catch (MyException e) {
                    System.out.println("第" + (i + 1) + "科成绩输入有误：" + e.getMessage());
                    System.exit(0);
                }
            }
        }
    }

    public double sum() throws MyException {
        double sum = 0;
        for (double s : score) {
            if (s < 0) {
                throw new MyException("成绩不能为负");
            }
            sum += s;
        }
        return sum;
    }

    public void display() throws MyException {
        System.out.println("学生姓名：" + name);
        System.out.print("四科成绩：");
        for (double s : score) {
            if (s < 0) {
                throw new MyException("成绩不能为负");
            }
            System.out.print(s + " ");
        }
        System.out.println();

        System.out.println("学生总成绩：" + sum());
    }
}

Main.java

public class Main {
    public static void main(String[] args) throws MyException {
        Student student = new Student();
        student.display();
    }
}

第二种写法：

MyException.java

public class MyException extends Exception {
    public MyException(String message) {
        super(message);
    }
}

Student.java

import java.util.Scanner;

public class Student {
    private String name;
    private double[] score;

    public Student() {
        Scanner scanner = new Scanner(System.in);

        System.out.print("请输入学生姓名：");
        name = scanner.nextLine();

        score = new double[4];
        for (int i = 0; i < score.length; i++) {
            System.out.print("请输入第" + (i + 1) + "科成绩：");
            score[i] = scanner.nextDouble();
        }
    }

    public double sum() throws MyException {
        double sum = 0;
        for (double s : score) {
            if (s < 0) {
                throw new MyException("成绩不能为负");
            }
            sum += s;
        }
        return sum;
    }

    public void display() throws MyException {
        System.out.println("学生姓名：" + name);
        System.out.print("四科成绩：");
        for (double s : score) {
            if (s < 0) {
                throw new MyException("成绩不能为负");
            }
            System.out.print(s + " ");
        }
        System.out.println();

        System.out.println("学生总成绩：" + sum());
    }
}

Main.java

public class Main {
    public static void main(String[] args) {
        Student student = new Student();

        try {
            student.display();
        } catch (MyException e) {
            System.out.println("输入有误：" + e.getMessage());
        }
    }
}