包含对象数组列表的java序列化对象

Question

public class User  implements  Serializable{

    public String name;
    public String surname;
    public List<Picked> pickedBooks = new ArrayList<>();

    // Code omitted.
}

然后是班级选拔：

public class Picked {

    public Book book;
    public int period;
    public int cost;

    // Code omitted.
}

教材：

public class Book {

    public String name;
    public String bookTitle;
    public int howMany;

    // Code omitted.
}

因此，我主要创建新用户并将其序列化：

User user = new User();
user.setName("John");
user.setSurname("James");
String fileName = "data.bin";
try (ObjectOutputStream os = new ObjectOutputStream(new FileOutputStream(fileName))) {
    os.writeObject(user);
} catch (IOException ex) {
    Logger.getLogger(Library.class.getName()).log(Level.SEVERE, null, ex);
}

一切都很完美，但如果我这样做：

Book book = new Book("Dan Brown", "Angels and Demons", 1);
Picked pck = new Picked(book, 20, 2);
user.add(pck);

然后我想序列化对象用户，程序崩溃了。 我得到的结果是：

java.io.NotSerializableException: at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1183) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:347) at java.util.ArrayList.writeObject(ArrayList.java:742) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:606) at java.io.ObjectStreamClass.invokeWriteObject(ObjectStreamClass.java:988) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1495) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1431) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1177) at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1547) at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1508) at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1431) at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1177) at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:347)

Answer 1

Picked和Book也需要实现Serializable

Answer 2

如果您的对象没有实现java。木卫一。Serializable此代码抛出NotSerializableException，这同样适用于其所有非静态和非瞬态数据成员，以此类推，直到闭包。使用指定的SerialVersionUID更好，所以JVM不会在运行时计算它。还请实现可序列化到Picked和Book类

对于数组或集合，数组或集合的所有对象都必须是可序列化的。如果任何对象不可序列化，则序列化将失败

如果类中有内部类，则内部类始终包含对其外部类的隐式引用，则无法序列化内部类，除非外部类也可序列化。实际上，甚至不建议尝试

查看此引用http://docs.oracle.com/javase/7/docs/platform/serialization/spec/serial-arch.html#4539