Probleme beim Lesen mit readObject -> InvalidClassExcepti

[Veritas696]

Hallo Javafriends,

ich habe folgendes Problem: Ich habe ein Programm geschrieben mit welchem ich ein Object per Serialisierung in einer Datei abspeichern will und bei einem Neustart des Programms wieder laden möchte.

Ich habe des Programme an einem Rechner geschrieben und wollte jetzt an einem anderen Rechner weiterentwickeln.

nun bekomme ich aber folgende Fehlermeldung wenn ich das Programm starte:


java.io.InvalidClassException: javax.swing.JComponent; local class incompatible: stream classdesc serialVersionUID = -2514362798440941654, local class serialVersionUID = -1030230214076481435
at java.ibjectStreamClass.initNonProxy(Unknown Source)
at java.ibjectInputStream.readNonProxyDesc(Unknown Source)
at java.ibjectInputStream.readClassDesc(Unknown Source)
at java.ibjectInputStream.readNonProxyDesc(Unknown Source)
at java.ibjectInputStream.readClassDesc(Unknown Source)
at java.ibjectInputStream.readNonProxyDesc(Unknown Source)
at java.ibjectInputStream.readClassDesc(Unknown Source)
at java.ibjectInputStream.readNonProxyDesc(Unknown Source)
at java.ibjectInputStream.readClassDesc(Unknown Source)
at java.ibjectInputStream.readOrdinaryObject(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.defaultReadFields(Unknown Source)
at java.ibjectInputStream.readSerialData(Unknown Source)
at java.ibjectInputStream.readOrdinaryObject(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.readArray(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.defaultReadFields(Unknown Source)
at java.ibjectInputStream.readSerialData(Unknown Source)
at java.ibjectInputStream.readOrdinaryObject(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.defaultReadFields(Unknown Source)
at java.ibjectInputStream.readSerialData(Unknown Source)
at java.ibjectInputStream.readOrdinaryObject(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.defaultReadFields(Unknown Source)
at java.ibjectInputStream.readSerialData(Unknown Source)
at java.ibjectInputStream.readOrdinaryObject(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.readArray(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.defaultReadFields(Unknown Source)
at java.ibjectInputStream.readSerialData(Unknown Source)
at java.ibjectInputStream.readOrdinaryObject(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.defaultReadFields(Unknown Source)
at java.ibjectInputStream.readSerialData(Unknown Source)
at java.ibjectInputStream.readOrdinaryObject(Unknown Source)
at java.ibjectInputStream.readObject0(Unknown Source)
at java.ibjectInputStream.readObject(Unknown Source)
at poker.database.DataBase.loadDataBase(DataBase.java:43)
at mainpack.StartUp.main(StartUp.java:54)



Wie kann ich die Daten aus der Datei auslesen ohne eine neue Datei anzulegen?

Wie gesagt ich hab nicht einmal was an den Dateien geändert: an dem einem Rechner gings und jetzt plötzlich nicht mehr :-(

 

[Veritas696]

So lesen ich das Objekt aus der Datei aus:

public void loadDataBase()
	{	
		Debugger.outln("DataBase DATEN LADEN !");
		FileInputStream fis = null;
		ObjectInputStream ois = null;
		try
		{
			fis = new FileInputStream("PokerDB.tmp");
			ois = new ObjectInputStream(fis);
			ProfileManager.setInstance((ProfileManager) ois.readObject());
			ois.close();
		} 
		catch (FileNotFoundException e)
		{
			MainFrame.getInstance().showInfoDialog("Noch keine Daten vorhanden", "BRManager");
			e.printStackTrace();
		}		
		catch (IOException e)
		{
			MainFrame.getInstance().showInfoDialog("IOException", "BRManager");
			e.printStackTrace();
		}
		catch (ClassNotFoundException e)
		{
			MainFrame.getInstance().showInfoDialog("ClassNotFoundException", "BRManager");
			e.printStackTrace();
		}
			
						
	}

und so Speicher ich es wieder:

/////////////////////////////////////////////////////////////////////////////////
	public void saveDataBase() throws IOException, ClassNotFoundException
	{
		Debugger.outln("DataBase DATEN SPEICHERN !");
		FileOutputStream 		fos = new FileOutputStream("PokerDB.tmp");
		ObjectOutputStream 	oos = new ObjectOutputStream(fos);
		
		oos.writeObject(ProfileManager.getInstance());
		
		oos.close();				
	}

 

[Landei]

Deine Klasse hat keine serialVersionUID, also berechnet dir der Compiler eine. Nun können sich entweder die Definition der Klasse auf dem anderen Rechner oder der Algorithmus zur Berechnung der serialVersionUID bei verschiedenen Java-Versionen unterscheiden. Probiere mal

	private final static long serialVersionUID = 1;

in deine Klasse einzufügen, vielleicht geht's dann. Wenn du unbedingt die alten, schon serialisierten Objekte lesen willst, brauchst du natürlich

   private final static serialVersionUID = -2514362798440941654

 

[FArt]

Aus http://java.sun.com/j2se/1.5.0/docs/api/java/io/Serializable.html:

The serialization runtime associates with each serializable class a version number, called a serialVersionUID, which is used during deserialization to verify that the sender and receiver of a serialized object have loaded classes for that object that are compatible with respect to serialization. If the receiver has loaded a class for the object that has a different serialVersionUID than that of the corresponding sender's class, then deserialization will result in an InvalidClassException. A serializable class can declare its own serialVersionUID explicitly by declaring a field named "serialVersionUID" that must be static, final, and of type long:

ANY-ACCESS-MODIFIER static final long serialVersionUID = 42L;

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.