通过添加某个包中的所有类来在 Hibernate 中添加带注释的类。 JAVA

Question

有什么方法可以循环（例如通过for）某个包中的所有类吗？ 我必须

addAnnotatedClass(Class c)

AnnotationConfiguration

。 这样做：

    AnnotationConfiguration annotationConfiguration.addAnnotatedClass(AdditionalInformation.class);
    annotationConfiguration.addAnnotatedClass(AdditionalInformationGroup.class);
    annotationConfiguration.addAnnotatedClass(Address.class);
    annotationConfiguration.addAnnotatedClass(BankAccount.class);
    annotationConfiguration.addAnnotatedClass(City.class);
    //et cetera

我所有的桌子都在包装中

Tables.Informations

。

Answer 1

正如评论中提到的，使用 AnnotationConfiguration API 无法实现加载包中所有类的功能。以下是您可以使用上述 API 执行的一些操作（请注意，“addPackage”方法仅读取包元数据，例如在 package-info.java 类中找到的元数据，它不会加载包中的所有类）：

http://docs.jboss.org/hibernate/annotations/3.5/reference/en/html/ch01.html

sessionFactory = new AnnotationConfiguration()
                    .addPackage("test.animals") //the fully qualified package name
                    .addAnnotatedClass(Flight.class)
                    .addAnnotatedClass(Sky.class)
                    .addAnnotatedClass(Person.class)
                    .addAnnotatedClass(Dog.class)
                    .addResource("test/animals/orm.xml")
                    .configure()
                    .buildSessionFactory();

Answer 2

以下代码遍历指定包中的所有类，并列出用“@Entity”注释的类。 这些类中的每一个都被添加到您的 Hibernate 工厂配置中，而无需显式地列出它们。

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<Class<?>> getEntityClassesFromPackage(String packageName) throws ClassNotFoundException, IOException, URISyntaxException {
    List<String> classNames = getClassNamesFromPackage(packageName);
    List<Class<?>> classes = new ArrayList<Class<?>>();
    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<String> getClassNamesFromPackage(String packageName) throws IOException, URISyntaxException, ClassNotFoundException {
    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
    ArrayList<String> names = new ArrayList<String>();

    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;
}

有用的参考：https://stackoverflow.com/a/7461653/7255

Answer 3

有一个很好的开源包，名为“org.reflections”。您可以在这里找到它：https://github.com/ronmamo/reflections

使用该包，您可以扫描如下实体：

Reflections reflections = new Reflections("Tables.Informations");
Set<Class<?>> importantClasses = reflections.getTypesAnnotatedWith(Entity.class);
for (Class<?> clazz : importantClasses) {
    configuration.addAnnotatedClass(clazz);
}

Answer 4

您可以使用 LocalSessionFactoryBuilder 来构建会话工厂，使您能够指定 scanPackages 属性。

SessionFactory sessionFactory = new LocalSessionFactoryBuilder(hikariDataSource())
        .scanPackages("com.animals.entities")
        .addProperties(properties)
        .buildSessionFactory();

Answer 5

对于 Hibernate 6.* 版本，实现方法是：

public class HibernateUtils {
private static SessionFactory sessionFactory;

static {
    try {
        Properties props = new Properties();
        props.load(HibernateUtils.class.getClassLoader().getResourceAsStream("hibernate.properties"));

        ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder()
                .applySettings(props)
                .build();

        MetadataSources metadataSources = new MetadataSources(serviceRegistry);

        Reflections reflections = new Reflections("io.github.gustavo.model");
        Set<Class<?>> entityClasses = reflections.getTypesAnnotatedWith(Entity.class);

        entityClasses.forEach(metadataSources::addAnnotatedClass);

        Metadata metadata = metadataSources.getMetadataBuilder().build();

        sessionFactory = metadata.getSessionFactoryBuilder().build();
    } catch(Exception e) {
        throw new ExceptionInInitializerError("Falha ao inicializar a Session Factory");
    }
}

lib 反思：

<dependency>
        <groupId>org.reflections</groupId>
        <artifactId>reflections</artifactId>
        <version>0.10.2</version>
</dependency>