使用JFileChooser打开txt文件并填充ArrayList

Question

I have a Person class with ID, name, address and state instance variables

• The ID have no setter(mutator) method
• name,address and state instance variables have both setter and getter methods -The txt file to read in from is comma delimited

I want to open a txt file using JFileChooser and then pupulate the Person class type ArrayList by reading in line. I get stacked to set the read in ID to the Person object here is the method to read in and poupulate the arraylist

public static ArrayList<Person> load(String fileName) throws IOException {
    ArrayList<person> lines = null;
    BufferedReader reader;
    try {
        JFileChooser chooser = new JFileChooser();
        chooser.setDialogTitle("Load which file?");
        int result = chooser.showOpenDialog(null);
        if (result == JFileChooser.APPROVE_OPTION) {
            File file = chooser.getSelectedFile();
            if (file != null) {
                fileName = file.getCanonicalPath();
                reader
                        = new BufferedReader(new FileReader(fileName));
                lines = new ArrayList<>();

                String line = reader.readLine();
                String data[];
                while ((line = reader.readLine()) != null) {
                    data = line.split(",");
                    Person s = new Person();


                     s.setName(data[0]);
                     s.setAddress(data[1]);
                    s.setState(data[2]);

                    //I got stack how to set ID bcs it has no set method

                    s.getAddress();                                   
                    s.getName();
                    s.getState();

                    lines.addAll(Arrays.asList(s));
                }
                reader.close();
                return lines;
            }
        }

    } catch (FileNotFoundException exp) {
        exp.printStackTrace();
    } catch (IOException exp) {
        exp.printStackTrace();
    }
    return lines;
}

}

Answer 1

If you have decided that you dont want to change the ID after it assign, then you can overload the class constructor like below

public Person(int id){
    this.id = id;
}

then inside your method do like

data = line.split(",");
Person s = new Person(whatever_if_you_wanana_set);

Answer 2

You can not set ID if there isn't any setter or constructor that takes ID . Besides, why are you using

lines.addAll(Arrays.asList(s));

As s is an object of Person , you can simply call lines.add(s); to add person object to list.