下列能够判断Spring容器是否包含ID为proBean的Bean的代码为( )。 A.boolean flag = beanFactory.containsBean("proBean");B.PropertiesBean propertiesBean= (PropertiesBean)beanFactory.getBean("proBean");C.Class classType

A.boolean flag = beanFactory.containsBean("proBean");

B.PropertiesBean propertiesBean

= (PropertiesBean)beanFactory.getBean("proBean");

C.Class classType = beanFactory.getType("proBean");

D.PropertiesBean propertiesBean

= (PropertiesBean)beanFactory.getBean("proBean", PropertiesBean.class);