Add Annotated Class in Hibernate by adding all classes in some package. JAVA

Question

is there any way to loop (e.g. via for) all classes with are in some package? I have to addAnnotatedClass(Class c) on AnnotationConfigura

Answer 1

The following code goes through all the classes within a specified package and makes a list of those annotated with "@Entity". Each of those classes is added into your Hibernate factory configuration, without having to list them all explicitly.

public static void main(String[] args) throws URISyntaxException, IOException, ClassNotFoundException {
    try {
        Configuration configuration = new Configuration().configure();
        for (Class cls : getEntityClassesFromPackage("com.example.hib.entities")) {
            configuration.addAnnotatedClass(cls);
        }
        sessionFactory = configuration.buildSessionFactory();
    } catch (Throwable ex) {
        System.err.println("Failed to create sessionFactory object." + ex);
        throw new ExceptionInInitializerError(ex);
    }
}

public static List> getEntityClassesFromPackage(String packageName) throws ClassNotFoundException, IOException, URISyntaxException {
    List classNames = getClassNamesFromPackage(packageName);
    List> classes = new ArrayList>();
    for (String className : classNames) {
        Class cls = Class.forName(packageName + "." + className);
        Annotation[] annotations = cls.getAnnotations();

        for (Annotation annotation : annotations) {
            System.out.println(cls.getCanonicalName() + ": " + annotation.toString());
            if (annotation instanceof javax.persistence.Entity) {
                classes.add(cls);
            }
        }
    }

    return classes;
}

public static ArrayList getClassNamesFromPackage(String packageName) throws IOException, URISyntaxException, ClassNotFoundException {
    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
    ArrayList names = new ArrayList();

    packageName = packageName.replace(".", "/");
    URL packageURL = classLoader.getResource(packageName);

    URI uri = new URI(packageURL.toString());
    File folder = new File(uri.getPath());
    File[] files = folder.listFiles();
    for (File file: files) {
        String name = file.getName();
        name = name.substring(0, name.lastIndexOf('.'));  // remove ".class"
        names.add(name);
    }

    return names;
}

Helpful reference: https://stackoverflow.com/a/7461653/7255