可以举一个JPA helper的代码示例吗？

可以举一个JPA helper的代码示例吗？ 可以举一个JPA helper的代码示例吗？

import org.eclipse.persistence.jpa.JpaHelper; //导入依赖的package包/类 @Override public void collectAnswers(final QuestionnaireDefinition questionnaireDefinition) { Assert.notNull(questionnaireDefinition.getId()); final Session session = JpaHelper.getEntityManager(entityManager).getSession(); // DynamicClassLoader dcl = new // DynamicClassLoader(Thread.currentThread().getContextClassLoader()); final DynamicClassLoader dcl = DynamicClassLoader.lookup(session); // Create JPA Dynamic Helper (with the entityManager above) and after // the types // have been created and add the types through the helper. final JPADynamicHelper helper = new JPADynamicHelper(entityManager); helper.addTypes(true, true, buildDynamicType(dcl, questionnaireDefinition)); // Update database new SchemaManager(helper.getSession()).createDefaultTables(true); logger.info("Questionnaire answer table has been created for questionnaireDefinition {}", questionnaireDefinition.getId()); }