有没有办法从EntityManager获取所有托管实体

public List<Object> getAllEntities(EntityManager entityManager) {
    List<Object> entities = new ArrayList<>();
    List<String> entityClassNames = getEntityClassNames(); // 获取所有实体类的类名
    for (String entityClassName : entityClassNames) {
        try {
            Class<?> entityClass = Class.forName(entityClassName);
            Object entity = entityManager.find(entityClass, 1); // 假设每个实体都有一个id为1的记录
            if (entity != null) {
                entities.add(entity);
            }
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    return entities;
}