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懒得笔记4 spring annotation

发表于: 2015-08-13 ? 作者:chen_xinjia ? 来源:转载 ? 浏览:
摘要: 1,要加入aop包,不然会报??org.springframework.beans.factory.BeanDefinitionStoreException:UnexpectedexceptionparsingXMLdocumentfromclasspathresource????????[beans.xml];nested???????exceptionisjava.lang.NoClassDe

1, 要加入 aop 包, 不然会报

? ? org.springframework.beans.factory.BeanDefinitionStoreException: Unexpected exception parsing XML document from class path resource ? ? ? ? ? ? ? ?[beans.xml]; nested ? ? ? ? ? ? ?exception is java.lang.NoClassDefFoundError: org/springframework/aop/TargetSource

2,xml 文档

? ??




    



3,注解

? ? 1,@Autowired

? ? ?按类型再按名字@qualifier

? ? ? ? 在setter之前标志(As expected, you can apply the?@Autowired?annotation to "traditional" setter methods:)

? ? 2,@Required

? ? ??This annotation simply indicates that the affected bean property must be populated at configuration time, through an explicit property value in a bean definition or through autowiring. The container throws an exception if the affected bean property has not been populated; this allows for eager and explicit failure, avoiding NullPointerExceptions or the like later on. It is still recommended that you put assertions into the bean class itself, for example, into an init method. Doing so enforces those required references and values even when you use the class outside of a container.


? ? ?仅仅在亚博国际平台时就用于检测是否有合适的值与bean亚博国际平台。防止出现NullPointerExceptions?

? 3,@Resource(name="UserDAO")

? ? ?按名字再按类型

?4,@component

? ? ? ?在xml中加入以下这句话,便可以不用在xml里定义 bean 系统自动到指定的地方去扫描找到对应的bean,写在对应的类里

? ? ?

? ? ?在bean中加入?@Component("u") ?来指定bean 的id 也可不写,默认为类名小写


懒得笔记4 spring annotation

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