不幸的是,问题标题中的情况已经发生在几年前。
我有一个Id
接口,它扩展Serializable
并包含名称和 ID 号的 getter。有一个IdImpl
实现接口的匹配类。然而,在过去的某个时候,Id
是班级。还有一个可序列化的容器对象,其成员字段类型为Id
。这些容器对象已经被序列化到数据库好几年了,所以有容器对象的版本包含这两种类型的Id
s。当试图反序列化旧对象时,我们得到一个InvalidClassException
. 如何反序列化包含旧Id
具体类实例的旧容器对象?
Id
全面披露:多年来对界面进行了一些其他更改,但我认为它们看起来像兼容的更改(为 "String idType"添加了一个字段IdImpl
和一个 getter ;generified )。这些变化之一是否也会导致问题?Id
Comparable
这些类看起来像这样:
// current Id interface
public interface Id extends Serializable, Comparable<Id> {
String getName();
int getIdNumber();
}
// current Id implementation
public class IdImpl implements Id {
private static final long serialVersionUID = 10329865109284L;
private String name;
private int idNumber;
IdImpl(String name, int idNumber) { this.name = name; this.idNumber = idNumber; }
@Override public String getName() { return name; }
@Override public int getIdNumber() { return idNumber; }
@Override public int compareTo(Id id) { /* some code here */ }
}
// the container object
public ContainerForm implements Serializable {
private static final long serialVersionUID = -3294779665912049275L;
private String someField;
private Id user;
private String someOtherField;
// getters and setters
}
// this is what the _old_ Id concrete class looked like
// (from source control history; not in current project)
public class Id implements Serializable, Comparable {
// never had a serialVersionUID
private String name;
private int idNumber;
Id(String name, int idNumber) { this.name = name; this.idNumber = idNumber; }
public String getName() { return name; }
public int getIdNumber() { return idNumber; }
public int compareTo(Object id) { /* some code here */ }
}
我们在尝试反序列化容器对象时遇到的异常是:
java.io.InvalidClassException: mypkg.people.Id; local class incompatible: stream classdesc serialVersionUID = -6494896316839337071, local class serialVersionUID = -869017349143998644
at java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:562)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1583)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1496)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1732)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1947)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1871)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
at mypkg.forms.FormFactory.getForm(FormFactory.java:3115)
... 34 more