/**
* Used to dereference a {@link FactoryBean} instance and distinguish it from
* beans <i>created</i> by the FactoryBean. For example, if the bean named
* <code>myJndiObject</code> is a FactoryBean, getting <code>&myJndiObject</code>
* will return the factory, not the instance returned by the factory.
*/
String FACTORY_BEAN_PREFIX = "&";
彪悍的人生不需要解释
Object getBean(String name) throws BeansException;
Object getBean(String name, Class requiredType) throws BeansException;返回以给定名称注册的bean实例，并转换为给定class类型的实例，如果转换失败，相应的异常(BeanNotOfRequiredTypeException)将被抛出。上面的getBean(String)方法也适用该规则.
Object getBean(String name, Object[] args) throws BeansException; 如果要创建的对象不为prototype 的话，就会抛出BeanDefinitionStoreException。
boolean containsBean(String name);
boolean isSingleton(String name) throws NoSuchBeanDefinitionException;
boolean isPrototype(String name) throws NoSuchBeanDefinitionException;
boolean isTypeMatch(String name, Class targetType) throws NoSuchBeanDefinitionException;
Class getType(String name) throws NoSuchBeanDefinitionException;
String[] getAliases(String name);