我怎么写＆amp;读取ArrayList对象到文件？

Question

在我的程序中，用户输入一些string和int值，并将它们存储在具有动态大小的ArrayList中。

现在我想将这些对象存储在磁盘上，以便在关闭应用程序后不会丢失任何数据。最后我想读取文件。我正在上课的是：ReaderWriter

我的代码：

主：

public class PeopleInfo {

        public static void main(String[] args) {
            System.out.println("WELCOME TO MY PERSONAL DATABASE\n\n");
            Scanner input = new Scanner(System.in);
            List<PeopleObject> peopleObject = new ArrayList<PeopleObject>();
            String name;
            int age;
            int option;

            while (true) {

                System.out.println("1. Enter info\n"
                        + "2. Print them out\n"
                        + "3. Exit\n"
                        + "*********"
                        + "*********\n");
                option = input.nextInt();
                input.nextLine();

                switch (option) {
                    case 1:
                        PeopleObject p_object = new PeopleObject();
                        System.out.println("Enter your friends name:");
                        p_object.setName(input.nextLine());
                        System.out.println("Enter age: ");
                        p_object.setAge(input.nextInt());

                        peopleObject.add(p_object);
                        System.out.println("\n");
                        break;
                    case 2:
                        System.out.println("Name \tage");
                        for (PeopleObject printPeopleObject : peopleObject) {
                            System.out.println(printPeopleObject);

                        }
                        System.out.println("\n\n");
                        break;
                    case 3:
                        return;
                }

            }

        }

    }

PeopleObject：

public class PeopleObject {

    private String name;
    private int age;

    public PeopleObject() {
        this.name = null;
        this.age = 0;

    }

    public void setName(String name) {
        this.name = name;
    }

    public void setAge(int age) {
        this.age = age;

    }

    @Override
    public String toString() {
        return name + "\t\t" + age;
    }

}

读写器：

public class ReaderWriter {
        //I want to use this class for storing my info in a file
        //and retrieving them

        public void writeToFile(){

            try{

            }catch(IndexOutOfBoundsException e){
                e.printStackTrace();
            }


        }
        public String readFromFile(){
            //return info;
        }

    }