尝试反序列化对象时出错。

huangapple
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标题翻译

Error when I try to deserialize an object

问题

  1. 我和我的朋友正在使用GitHub进行编码，在我们更新主类时，IDE提供了以下错误：
  3.     Exception in thread "main" java.io.InvalidClassException: Packages.contoCorrente; local class incompatible: stream classdesc serialVersionUID = -433050874178120905, local class serialVersionUID = -5213999116280532749
  4. 	at java.base/java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:689)
  5. 	at java.base/java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1958)
  6. 	at java.base/java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1827)
  7. 	at java.base/java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2115)
  8. 	at java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1646)
  9. 	at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:464)
  10. 	at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:422)
  11. 	at java.base/java.util.ArrayList.readObject(ArrayList.java:928)
  12. 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  13. 	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  14. 	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  15. 	at java.base/java.lang.reflect.Method.invoke(Method.java:566)
  16. 	at java.base/java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1160)
  17. 	at java.base/java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2271)
  18. 	at java.base/java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2142)
  19. 	at java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1646)
  20. 	at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:464)
  21. 	at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:422)
  22. 	at ObjectWrite.main(ObjectWrite.java:31)
  24. 为了解决这个问题，我总是删除主对象文件，以便它可以重新构建。我还附上了处理反序列化的代码部分，希望有人能帮助我。
  26. public static void main(String[] args) throws Exception {
  28.     ArrayList<contoCorrente> contiCorrentiArray;
  29.     File file = new File("contiCorrenti");
  30.     if (file.exists()) {
  31.         FileInputStream fileIn = new FileInputStream(file);
  32.         ObjectInputStream fileObjIn = new ObjectInputStream(fileIn);
  34.         //noinspection unchecked
  35.         contiCorrentiArray = (ArrayList<contoCorrente>) fileObjIn.readObject();
  37.         fileObjIn.close();
  38.         fileIn.close();
  39.     } else {
  40.         contiCorrentiArray = new ArrayList<>();
  41.     }
  43.     System.out.println("Numero Conti Presenti: " + contiCorrentiArray.size() + "\n");
  44. }
英文翻译

I am coding using GitHub with my friend, and when we update the main class, the IDE provides us the following error:

  1. Exception in thread &quot;main&quot; java.io.InvalidClassException: Packages.contoCorrente; local class incompatible: stream classdesc serialVersionUID = -433050874178120905, local class serialVersionUID = -5213999116280532749
  2. at java.base/java.io.ObjectStreamClass.initNonProxy(ObjectStreamClass.java:689)
  3. at java.base/java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1958)
  4. at java.base/java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1827)
  5. at java.base/java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2115)
  6. at java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1646)
  7. at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:464)
  8. at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:422)
  9. at java.base/java.util.ArrayList.readObject(ArrayList.java:928)
  10. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  11. at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
  12. at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
  13. at java.base/java.lang.reflect.Method.invoke(Method.java:566)
  14. at java.base/java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1160)
  15. at java.base/java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:2271)
  16. at java.base/java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2142)
  17. at java.base/java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1646)
  18. at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:464)
  19. at java.base/java.io.ObjectInputStream.readObject(ObjectInputStream.java:422)
  20. at ObjectWrite.main(ObjectWrite.java:31)

To fix the problem, I always delete the main object file, so it can rebuild it. I am also attaching the part of code that deals with deserialization, in the hope that someone will help me.

  1. public static void main(String[] args) throws Exception {
  3.         ArrayList&lt;contoCorrente&gt; contiCorrentiArray;
  4.         File file = new File(&quot;contiCorrenti&quot;);
  5.         if (file.exists()) {
  6.             FileInputStream fileIn = new FileInputStream(file);
  7.             ObjectInputStream fileObjIn = new ObjectInputStream(fileIn);
  9.             //noinspection unchecked
  10.             contiCorrentiArray = (ArrayList&lt;contoCorrente&gt;) fileObjIn.readObject();
  13.             fileObjIn.close();
  14.             fileIn.close();
  15.         } else {
  16.             contiCorrentiArray = new ArrayList&lt;&gt;();
  17.         }
  19.     System.out.println(&quot;Numero Conti Presenti: &quot; + contiCorrentiArray.size() + &quot;\n&quot;);

答案1

得分: 1

你和你的伴侣是否拥有相同的 serialVersionUID？

如果不是的话，你们两个都应该定义它，以防止它被自动计算。

根据文档：

如果一个可序列化的类没有显式地声明serialVersionUID，那么序列化运行时将根据类的各个方面计算出一个默认的serialVersionUID值，如Java(TM)对象序列化规范中所述。然而，强烈建议所有可序列化的类都显式地声明serialVersionUID值，因为默认的serialVersionUID计算对编译器实现可能因类细节而异，因此在反序列化过程中可能会导致意外的InvalidClassExceptions。因此，为了保证在不同的Java编译器实现之间具有一致的serialVersionUID值，可序列化的类必须声明一个显式的serialVersionUID值。还强烈建议在可能的情况下，显式的serialVersionUID声明使用private修饰符，因为这样的声明仅适用于立即声明的类 - serialVersionUID字段作为继承成员是没有用的。数组类不能声明显式的serialVersionUID，因此它们始终具有默认计算值，但是对于数组类，匹配的serialVersionUID值的要求被放宽了。

英文翻译

Do you and your Partner have the same serialVersionUID?

If not, you both should define it, so it doesn't get calculated automatically.

From the docs:

> If a serializable class does not explicitly declare a
> serialVersionUID, then the serialization runtime will calculate a
> default serialVersionUID value for that class based on various aspects
> of the class, as described in the Java(TM) Object Serialization
> Specification. However, it is strongly recommended that all
> serializable classes explicitly declare serialVersionUID values, since
> the default serialVersionUID computation is highly sensitive to class
> details that may vary depending on compiler implementations, and can
> thus result in unexpected InvalidClassExceptions during
> deserialization. Therefore, to guarantee a consistent serialVersionUID
> value across different java compiler implementations, a serializable
> class must declare an explicit serialVersionUID value. It is also
> strongly advised that explicit serialVersionUID declarations use the
> private modifier where possible, since such declarations apply only to
> the immediately declaring class--serialVersionUID fields are not
> useful as inherited members. Array classes cannot declare an explicit
> serialVersionUID, so they always have the default computed value, but
> the requirement for matching serialVersionUID values is waived for
> array classes. `

huangapple
  • 本文由 发表于 2020年3月16日 21:02:15
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