如何在本地保存和加载自定义对象的key？

import java.io.*;

public class ObjectStorageExample {
    public static void main(String[] args) {
        // 创建自定义对象
        CustomObject obj = new CustomObject("example");

        // 保存对象
        String key = "custom_object_key";
        saveObject(obj, key);

        // 加载对象
        CustomObject loadedObj = loadObject(key);
        System.out.println("Loaded object: " + loadedObj.getName());
    }

    // 保存对象到本地存储
    private static void saveObject(CustomObject obj, String key) {
        try {
            FileOutputStream fileOut = new FileOutputStream(key + ".ser");
            ObjectOutputStream out = new ObjectOutputStream(fileOut);
            out.writeObject(obj);
            out.close();
            fileOut.close();
            System.out.println("Object saved successfully.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // 从本地存储加载对象
    private static CustomObject loadObject(String key) {
        CustomObject obj = null;
        try {
            FileInputStream fileIn = new FileInputStream(key + ".ser");
            ObjectInputStream in = new ObjectInputStream(fileIn);
            obj = (CustomObject) in.readObject();
            in.close();
            fileIn.close();
            System.out.println("Object loaded successfully.");
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
        return obj;
    }
}

// 自定义对象需要实现Serializable接口
class CustomObject implements Serializable {
    private String name;

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

    public String getName() {
        return name;
    }
}