我已经试着解决这些问题三天了，但没有达到我的预期效果。以下是说明和代码：
说明：
人员等级
学生类继承自person：最重要的是favsubject属性的数据类型是arraylist
师承人
printinfo类包含：构造函数、print方法和readfromfile方法
人员类别：

public class Person {

    protected String name;

    public Person(String name){
        this.name = name;
    }

    //setter and getter

    @Override
    public String toString(){
        return this.name;
    }
}

学生班级：

public class Student extends Person {

    private String id;
    private ArrayList<String> favSubject;
    private double score;

    public Student(String name, String id, ArrayList<String> favSubject, double score){
        super(name);
        this.id = id;
        this.favSubject = favSubject;
        this.score = score;
    }

    //setter and getter

    @Override
    public String toString(){
        return this.name + "-" + this.id + "-" + this.favSubject + "-" + this.score;
    }
}

教师班级：

public class Teacher extends Person {

    private String subject;

    public Teacher(String name, String subject){
        super(name);
        this.subject = subject;
    }

    //setter and getter

    @Override
    public String toString(){
        return this.name + "-" + this.subject;
    }
}

printinfo类

import java.util.*;
import java.io.*;
import java.lang.String;
public class PrintInfo {

    private ArrayList<Person> persList;

    //Constructor
    public PrintInfo(String path, String path1) throws FileNotFoundException{
      persList = getInfoFromFile(path, path1);
    }

    //Print method
    public void printInfoList(){
      for(Person p : persList){
        System.out.println(p);
      }
    }

    //Read from file method
    public ArrayList<Person> getInfoFromFile(String path, String path1) throws FileNotFoundException{
        ArrayList<Person> result = new ArrayList<>();
        try {
            HashMap<String,ArrayList<String>> favSub = new HashMap<>();
            Scanner myReader1 = new Scanner(new File(path1));
            while (myReader1.hasNextLine()){
                String p = myReader1.nextLine();
                String[] spl = p.split(",");
                if (spl.length==3){
                    favSub.put(spl[0],new ArrayList<String>());
                    favSub.get(spl[0]).add(spl[1]);
                    favSub.get(spl[0]).add(spl[2]);
                }
                if (spl.length==2){
                    favSub.put(spl[0],new ArrayList<String>());
                    favSub.get(spl[0]).add(spl[1]);
                }
            }
            myReader1.close();
            Scanner myReader = new Scanner(new File(path));
            ArrayList<String> favSubject = new ArrayList<>();
            while (myReader.hasNextLine()) {
                String ps = myReader.nextLine();
                String[] split = ps.split(",");
                if (split.length==3){
                    Person t = new Teacher(split[1],split[2]);
                    result.add(t);
                }
                if (split.length==4){
                    for (String key : favSub.keySet()) {
                        if (key.equals(split[1])){
                            Object[] arr = favSub.get(key).toArray();
                            String[] spl2 = Arrays.copyOf(arr,arr.length,String[].class);
                            if (spl2.length==2){
                                favSubject.add(spl2[0]);
                                favSubject.add(spl2[1]);
                            }
                            if (spl2.length==1){
                                favSubject.add(spl2[1]);
                            }
                        }
                    }
                    Person s = new Student(split[2],split[1],favSubject,Double.parseDouble(split[3]));
                    result.add(s);
                }
            }
            myReader.close();
        } catch (FileNotFoundException e) {
            System.out.println("An error occurred.");
            e.printStackTrace();
        }
        return result;
    }
}

测试等级：

import java.util.*;
import java.io.*;
public class TestPerson {
    public static void main(String[] args) throws FileNotFoundException{
        PrintInfo a = new PrintInfo("ListOfPerson.txt", "FSInfo.txt");
        a.printInfoList();
    }
}

我想用getinfofromfile（）方法从listofperson（基本信息）和fsinfo（favsubject属性的收藏夹主题）两个文件中读取数据，然后将其显示在屏幕上
listofperson.txt文件：
结构：
学生：顺序，身份证，姓名，分数
老师：顺序，名字，科目

1, A01, David, 10
2, Kate, Physics
3, A02, John, 9
4, A03, Olivia, 9
5, Helen, Math
6, A04, Sarah, 8
7, Nick, History
8, A05, Jennie, 10
9, A06, Jeremy, 9
10, Mary, Chemistry

fsinfo.txt文件：
结构：id，最喜欢的主题

A01, Math, Physics
A02, Physics
A03, Chemistry, History
A04, Math, Geography
A05, Chemistry
A06, Biology

我想在屏幕上显示的内容：

David - A01 - [Math,Physics] - 10
Kate - Physic
John - A02 - [Physics] - 9
Olivia - A03 - [Chemistry,History] - 9
Helen - Math
Sarah - A04 - [Math,Geography] - 8
Nick - History
Jennie - A05 - [Chemistry] - 10
Jeremy - A06 - [Biology] - 9
Mary - Chemistry

这只是练习的开始，所以我必须解决这个问题，以满足更多的要求。非常感谢：））更新：我已经更新了printinfo类的代码，但这是屏幕上打印的内容

David - A01 - [] - 10
Kate - Physic
John - A02 - [] - 9
Olivia - A03 - [] - 9
Helen - Math
Sarah - A04 - [] - 8
Nick - History
Jennie - A05 - [] - 10
Jeremy - A06 - [] - 9
Mary - Chemistry