为什么我的变量没有重置每一个循环？

Question

我正在构建一个gradebook来存储学生和教师，每个学生和教师都有一个唯一的ID，以及他们各自在Student和Teacher对象的ArrayList中注册或教学的类。我有文件夹路径“j：/compsci/类/”，为每个类存储一个文本文件。

文本文件格式：

第1行：班级名称、教师ID、期间、荣誉？、班级ID

第2行：班级中每个学生的学生ID（用逗号分隔）。

在这里，我初始化了每个学生正在接受的所有类，每个老师正在教授的所有类，以及每个班级的所有学生和信息。

根据我到目前为止所学到的一切，我将在本地范围内重新定义类对象c，因此它应该是一个全新的对象，最初没有学生，但在下面的行中，当与调试一起打印时，它包括了以前所有类的学生。

请帮帮我我花了一个星期的时间来解决这个问题

带调试的代码

File[] classes = new File("J:/compsci/Classes/").listFiles();
for (File currentClass: classes) {
    System.out.println(currentClass.getPath());//proves that i'm moving to a different class
    try (Scanner fileReader = new Scanner (new FileInputStream (currentClass.getPath()))){
        String[] classInfo= fileReader.nextLine().split(",");
        for (String s: classInfo)//all the info going into the parameters for a new class
            System.out.print(s+",");
        System.out.println();
        Class c = new Class (classInfo[0],classInfo[1],Integer.parseInt(classInfo[2]),classInfo[3].equals("H"),currentClassID());
        for (Student s: c.getStudents())//PROBLEM!! should always be empty initially and not store students from previous classes!!
            System.out.print(s.getID()+",");
        System.out.println();
        String[] studentslist= fileReader.nextLine().split(",");
        for (String s: studentslist)
            c.addStudent((Student)getUserFromID(s));
        ((Teacher)getUserFromID(classInfo[1])).addClass(c);
        for (String s: studentslist) {//prints the only students that are actually supposed to be in the class
            System.out.println(s);
            ((Student)getUserFromID(s)).addClass(c);
        }
        CLASSLIST.add(c);//global arraylist storing all classes
    } catch (Exception e) {
        e.printStackTrace();
    }
}

控制台输出

J:\compsci\Classes\APBiology.txt
AP Biology,00009,5,H,00001,

00001
00003
00004
00011
J:\compsci\Classes\Chinese5AP.txt
Chinese 5 AP,00007,0,H,00002,
00001,00003,00004,00011,
00005
00011
J:\compsci\Classes\ComputerScienceA.txt
Computer Science A,00007,2,H,00003,
00001,00003,00004,00011,00005,00011,
00001
00002
00003
00004
00005
J:\compsci\Classes\ComputerSciencePrinciples.txt
Computer Science Principles,00007,3,H,00004,
00001,00003,00004,00011,00005,00011,00001,00002,00003,00004,00005,
00003
00004
00005
00011
00001

未经任何调试的代码

File[] classes = new File("J:/compsci/Classes/").listFiles();
for (File currentClass: classes) {
    try (Scanner fileReader = new Scanner (new FileInputStream (currentClass.getPath()))){
        String[] classInfo= fileReader.nextLine().split(",");
        String[] studentslist= fileReader.nextLine().split(",");
        Class c = new Class (classInfo[0],classInfo[1],Integer.parseInt(classInfo[2]),classInfo[3].equals("H"),currentClassID());
        ((Teacher)getUserFromID(classInfo[1])).addClass(c);
        for (String s: studentslist)
            c.addStudent((Student)getUserFromID(s));
        for (String s: studentslist)
            ((Student)getUserFromID(s)).addClass(c);
        CLASSLIST.add(c);//global arraylist storing all classes
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Answer 1

因为您在创建新的类C：

Class c = new Class (classInfo[0],classInfo[1],Integer.parseInt(classInfo[2]),classInfo[3].equals("H"),currentClassID());
for (Student s: c.getStudents())//PROBLEM!! should always be empty initially and not store students from previous classes!!

但是你没有附加你的类构造函数，我想你错过了reset List students Attriburte。请添加

学生=new arraylist<>()；

类构造函数。