hibernate 懒加载问题的一个临时解决方案

comxpp 2011-05-06

hibernate的懒加载问题时常会困扰着我们, 今天发现了hibernate自身也提供一些解决办法

Hibernate.initialize(company.getUsers());  这样就加载了users集合

但不支持递归加载

it is not guaranteed that the elements INSIDE the collection will be initialized/materialized

假如这时session关闭了  会报错

真正解决懒加载还是应该在类的设计 xml文件的配置上下功夫

源码:

/**
	 * Force initialization of a proxy or persistent collection.
	 * <p/>
	 * Note: This only ensures intialization of a proxy object or collection;
	 * it is not guaranteed that the elements INSIDE the collection will be initialized/materialized.
	 *
	 * @param proxy a persistable object, proxy, persistent collection or <tt>null</tt>
	 * @throws HibernateException if we can't initialize the proxy at this time, eg. the <tt>Session</tt> was closed
	 */
	public static void initialize(Object proxy) throws HibernateException {
		if ( proxy == null ) {
			return;
		}
		else if ( proxy instanceof HibernateProxy ) {
			( ( HibernateProxy ) proxy ).getHibernateLazyInitializer().initialize();
		}
		else if ( proxy instanceof PersistentCollection ) {
			( ( PersistentCollection ) proxy ).forceInitialization();
		}
	}

	/**
	 * Check if the proxy or persistent collection is initialized.
	 *
	 * @param proxy a persistable object, proxy, persistent collection or <tt>null</tt>
	 * @return true if the argument is already initialized, or is not a proxy or collection
	 */
	public static boolean isInitialized(Object proxy) {
		if ( proxy instanceof HibernateProxy ) {
			return !( ( HibernateProxy ) proxy ).getHibernateLazyInitializer().isUninitialized();
		}
		else if ( proxy instanceof PersistentCollection ) {
			return ( ( PersistentCollection ) proxy ).wasInitialized();
		}
		else {
			return true;
		}
	}

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