java - 我有一个以文件名作为输入的方法，应该返回一个数组作为输出。该文件包含带有科目名称和分数的学生记录

Question

我有一个 Student 类，在主类中我有一个方法，该方法采用 fileName(该文件包含带有科目名称和分数的学生记录)作为输入，并返回一个 Student 数组作为输出。

我尝试使用 ArrayList，但是我无法将学生的记录转换为学生数组。请帮助..下面是我的代码:

public static void main(String[] args) throws FileNotFoundException {
    String filename = "student.txt";
    readData(filename);
}

private static Student[] readData(String filename) throws FileNotFoundException{
    Scanner input = new Scanner(new File(filename));

    ArrayList<Student> list = new ArrayList<Student>();
    while(input.hasNext()){
        String name = input.next();
        int physic = input.nextInt();
        int chemistry = input.nextInt();
        int math = input.nextInt();
        Student studentR = new Student(name,physic,chemistry,math);
        list.add(studentR);
        System.out.println(list);
    }
    for (Student studentR : list) {
        System.out.println(studentR);
        return studentR;
    }
}

我的文本文件如下所示:

Amy 85 95 78
Nancy 83 93 82
Richard 81 91 86
Daniel 77 78 79
James 80 90 85
Cathy 95 74 89
Paul 84 87 79

以下是我收到的错误:

Main.java:28: error: incompatible types: Student cannot be converted to Student[]
                        return studentR;
                               ^

Answer 1

试试这个代码:

 public static void main(String[] args) throws FileNotFoundException {
     String filename = "student.txt";
     readData(filename);
 }

 private static List < Student > readData(String filename) throws FileNotFoundException {
     Scanner input = new Scanner(new File(filename));
     List < Student > list = new List < Student > ();

     while (input.hasNext()) {
         String name = input.next();
         int physic = input.nextInt();
         int chemistry = input.nextInt();
         int math = input.nextInt();
         Student studentR = new Student(name, physic, chemistry, math);
         list.add(studentR);
         System.out.println(list);
     }

     for (Student studentR: list) {
         System.out.println(studentR);
     }

     return list;
 }