先声明输入流再声明输出流出现java.io.EOFException，但是先声明输出流再声明输入流却不会报错

# 具体遇到的问题

# 报错信息的截图

java.io.EOFException

at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2353)

at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:2822)

at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:804)

at java.io.ObjectInputStream.<init>(ObjectInputStream.java:301)

# 相关课程内容截图

# 尝试过的解决思路和结果

            FileOutputStream fos = new FileOutputStream("D:\\Product.txt");
        ObjectOutputStream oos = new ObjectOutputStream(fos);
        FileInputStream fis = new FileInputStream("D:\\Product.txt");
        ObjectInputStream ois = new ObjectInputStream(fis);

# 粘贴全部相关代码，切记添加代码注释（请勿截图）

public class Product implements Serializable {
private String id;
    private String name;
    private String categories;
    private double price;

    public Product(String id, String name, String categories, double price) {
this.id = id;
        this.name = name;
        this.categories = categories;
        this.price = price;
    }

@Override
    public String toString() {
return "产品ID：" + id +
"\n产品属性：" + name +
"\n产品属性：" + categories +
"\n产品价格：" + price;
    }

public static void main(String[] args) {
try {
            Product iphone = new Product("123", "iphone", "telephone", 4888.0);
        Product ipad = new Product("234", "ipad", "computer", 5088.0);
        Product macbook = new Product("345", "macbook", "computer", 10688.0);
        Product iwatch = new Product("256", "iwatch", "watch", 4799.0);

        FileInputStream fis = new FileInputStream("D:\\Product.txt");
            ObjectInputStream ois = new ObjectInputStream(fis);
            FileOutputStream fos = new FileOutputStream("D:\\Product.txt");
            ObjectOutputStream oos = new ObjectOutputStream(fos);

        oos.writeObject(iphone);
        oos.writeObject(ipad);
        oos.writeObject(macbook);
        oos.writeObject(iwatch);
        oos.writeObject(null);
        oos.flush();

        Product product;
        while ((product = (Product) ois.readObject()) != null)
                System.out.println(product.toString());

        oos.close();
        fos.close();
        ois.close();
        fis.close();
    } catch (FileNotFoundException e) {
        System.out.println("File Not Found...");
    } catch (IOException e) {
        e.printStackTrace();
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    }

}