休眠会话工厂Android

Question

I'm trying to use Hibernate on Android. (Eclipse Android 2.2 SDK)
It seems there is a compile error in line containing

HibernateUtility.getSessionFactory().openSession();  

Here's HibernateUtility Class:

public class HibernateUtility {

    private static final SessionFactory sessionFactory;

    static {
        try {
            // Create the SessionFactory from standard (hibernate.cfg.xml) 
            // config file.
            sessionFactory = new Configuration().configure().buildSessionFactory();
        } catch (Throwable ex) {
            // Log the exception. 
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

The compile error in eclipse is:

The type javax.naming.Referenceable cannot be resolved. It is indirectly referenced from required .class files

I've copied a file rt.jar from my java sdk (Sun JDK macosx) which contains the package javax.namaing.* and the compile error seems to be solved. But I now get the runtime error below from Android SDK Logcat.

08-30 15:21:05.123: W/dalvikvm(240): VFY: unable to find class referenced in signature (Lorg/hibernate/SessionFactory;) 08-30 15:21:05.123: I/dalvikvm(240): Could not find method org.hibernate.SessionFactory.openSession, referenced from method com.example.testfordatabase.EtityDao.insert 08-30 15:21:05.123: W/dalvikvm(240): VFY: unable to resolve interface method 102: Lorg/hibernate/SessionFactory;.openSession ()Lorg/hibernate/classic/Session; 08-30 15:21:05.123: D/dalvikvm(240): VFY: replacing opcode 0x72 at 0x000b 08-30 15:21:05.123: D/dalvikvm(240): VFY: dead code 0x000e-003f in Lcom/example/testfordatabase/EtityDao;.insert (Lcom/example/testfordatabase/entity;)V 08-30 15:21:05.123: D/step1(240): Step1 08-30 15:21:05.133: E/dalvikvm(240): Could not find class 'org.hibernate.cfg.Configuration', referenced from method com.example.testfordatabase.HibernateUtility. 08-30 15:21:05.133: W/dalvikvm(240): VFY: unable to resolve new-instance 65 (Lorg/hibernate/cfg/Configuration;) in Lcom/example/testfordatabase/HibernateUtility; 08-30 15:21:05.133: D/dalvikvm(240): VFY: replacing opcode 0x22 at 0x0000 08-30 15:21:05.133: D/dalvikvm(240): VFY: dead code 0x0002-000f in Lcom/example/testfordatabase/HibernateUtility;. ()V 08-30 15:21:05.133: W/dalvikvm(240): VFY: unable to find class referenced in signature (Lorg/hibernate/SessionFactory;) 08-30 15:21:05.133: W/System.err(240): Initial SessionFactory creation failed.java.lang.NoClassDefFoundError: org.hibernate.cfg.Configuration 08-30 15:21:05.133: W/dalvikvm(240): Exception Ljava/lang/ExceptionInInitializerError; thrown during Lcom/example/testfordatabase/HibernateUtility;. 08-30 15:21:05.133: D/AndroidRuntime(240): Shutting down VM 08-30 15:21:05.133: W/dalvikvm(240): threadid=1: thread exiting with uncaught exception (group=0x4001d800) 08-30 15:21:05.173: E/AndroidRuntime(240): FATAL EXCEPTION: main 08-30 15:21:05.173: E/AndroidRuntime(240): java.lang.ExceptionInInitializerError 08-30 15:21:05.173: E/AndroidRuntime(240): at com.example.testfordatabase.EtityDao.insert(EtityDao.java:35) 08-30 15:21:05.173: E/AndroidRuntime(240): at com.example.testfordatabase.MainActivity$1.onClick(MainActivity.java:34) 08-30 15:21:05.173: E/AndroidRuntime(240): at android.view.View.performClick(View.java:2408) 08-30 15:21:05.173: E/AndroidRuntime(240): at android.view.View$PerformClick.run(View.java:8816) 08-30 15:21:05.173: E/AndroidRuntime(240): at android.os.Handler.handleCallback(Handler.java:587) 08-30 15:21:05.173: E/AndroidRuntime(240): at android.os.Handler.dispatchMessage(Handler.java:92) 08-30 15:21:05.173: E/AndroidRuntime(240): at android.os.Looper.loop(Loope r.java:123) 08-30 15:21:05.173: E/AndroidRuntime(240): at android.app.ActivityThread.main(ActivityThread.java:4627) 08-30 15:21:05.173: E/AndroidRuntime(240): at java.lang.reflect.Method.invokeNative(Native Method) 08-30 15:21:05.173: E/AndroidRuntime(240): at java.lang.reflect.Method.invoke(Method.java:521) 08-30 15:21:05.173: E/AndroidRuntime(240): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 08-30 15:21:05.173: E/AndroidRuntime(240): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 08-30 15:21:05.173: E/AndroidRuntime(240): at dalvik.system.NativeStart.main(Native Method) 08-30 15:21:05.173: E/AndroidRuntime(240): Caused by: java.lang.ExceptionInInitializerError 08-30 15:21:05.173: E/AndroidRuntime(240): at com.example.testfordatabase.HibernateUtility.(HibernateUtility.java:31) 08-30 15:21:05.173: E/AndroidRuntime(240): ... 13 more 08-30 15:21:05.173: E/AndroidRuntime(240): Caused by: java.lang.NoClassDefFoundError: org.hibernate. cfg.Configuration 08-30 15:21:05.173: E/AndroidRuntime(240): at com.example.testfordatabase.HibernateUtility.(HibernateUtility.java:27)

plz help :D thanks

Answer 1

Not all standart java classes are available on android. One of them is package javax.naming - that's why you get this porblem. You may add missing classes from other sources though. ( or even rip them orr rt.jar ) - but doing this you may end up duplicating complete java runtime. I find that hibernate is a bit too heavyweight for android anyway.