从另一个Maven存储库工件中获取所有休眠注释/实体

Question

Can I get all entity or hibernate annotations from another maven repository artifact to my project?

In this case I want to add all entities from a package inside an artifact that I create. all i found is give setting like <class> or <jar-file> in the persistence.xml file. like:

<class>id.co.test.domain.Entity1</class>
<class>id.co.test.domain.Entity2</class>
<class>id.co.test.domain.Entity3</class>

So that class will be included in my project, while the artifact may modified(cant use <class> ) or get the version changed(cant use <jar-file> )

Is there any way to import any entities inside that one package id.co.test.domain to my project?

Answer 1

You could define a filter like this (Spring, but you can also do it with other libraries, or you can program the class scanning yourself):

Then use a class scanner to retrieve you all classes that have that annotations and add them to your hibernate configuration:

hibernate: create Entity(with annotations) in runtime I have also attached some code, which, while not perfect, can get your creative juices flowing. It is Spring based, but below, i will summarize the idea as well in pseudo code.

private static final TypeFilter[] ENTITY_TYPE_FILTERS = new TypeFilter[] {
        new AnnotationTypeFilter(Entity.class, false),
        new AnnotationTypeFilter(Embeddable.class, false),
        new AnnotationTypeFilter(MappedSuperclass.class, false)};

private void scanPackages(Configuration conf, String... packagesToScan) throws HibernateException {
        try {
            for (String pkg : packagesToScan) {
                String pattern = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
                        ClassUtils.convertClassNameToResourcePath(pkg) + RESOURCE_PATTERN;
                Resource[] resources = resourcePatternResolver.getResources(pattern);
                MetadataReaderFactory readerFactory = new CachingMetadataReaderFactory(resourcePatternResolver);
                for (Resource resource : resources) {
                    if (resource.isReadable()) {
                        MetadataReader reader = readerFactory.getMetadataReader(resource);
                        String className = reader.getClassMetadata().getClassName();
                        if (matchesFilter(reader, readerFactory)) {
                            conf.addAnnotatedClass(resourcePatternResolver.getClassLoader().loadClass(className));
                        }
                    }
                }
            }
        }
        catch (IOException | ClassNotFouncException ex) {
            throw new MappingException("Failed to scan classpath for unlisted classes", ex);
        }
    }

Basically you should follow the following steps:

1. Find the place where you bootstrap hibernate.

2. Find a way to scan all classes in your external jar that you need to be put in hibernate, that would most commonly be classes annnotated with @Entity, @MappedSuperClass and @Embedded.

3. Use Hibernate's configuration.addAnnotatedClass method ot add those classes to your hibernate config

http://docs.jboss.org/hibernate/orm/3.6/javadocs/org/hibernate/cfg/Configuration.html#addAnnotatedClass(java.lang.Class)