原文出处:http://blog.csdn.net/wxy_g/article/details/2071662
有很多人问Struts2.0中的对象既然都是线程安全的,都不是单例模式,那么它究竟何时创建,何时销毁呢?
这个和struts2.0中的配置有关,我们来看struts.properties
### if specified, the default object factory can be overridden here ### Note: short-hand notation is supported in some cases, such as "spring" ### Alternatively, you can provide a com.opensymphony.xwork2.ObjectFactory subclass name here struts.objectFactory = spring
如果我们使用的是com.opensymphony.xwork2.ObjectFactory ,老实说,我也没有研究过,xwork有一套像spring一样的IOC机制,小巧而简洁,有兴趣的朋友可以去研究下。struts2.0中的Action默认就是使用这种工厂模式的,我们来看
<action name="index" class="hdu.management.action.IndexAction"> <result name="success">/input.jsp</result> <result name="testFTL" type="freemarker">/ftl/test.jsp</result> </action>
class属性必须写类的全名,通过这种方式配置后,action对象的生命周期到底怎么样,你就认命吧,反正你就记住xwork有一个对象池,它会自己分配的,应对每次客户端的请求,它都会创建一个新的实例,至于这个实例何时销毁,由XWORK来控制。
接下来,我们用spring来控制action的生命周期,关于action和spring的集成,我这里就不累述了。
<action name="index" class="index"> <result name="success">/input.jsp</result> <result name="testFTL" type="freemarker">/ftl/test.jsp</result> </action>
这里的class是spring配置文件中bean的id
我们来看看spring文档中关于生命周期这个章节
Scopes a single bean definition to a single object instance per Spring IoC container.
Scopes a single bean definition to any number of object instances.
Scopes a single bean definition to the lifecycle of a single HTTP request; that is each and every HTTP request will have its own instance of a bean created off the back of a single bean definition. Only valid in the context of a web-aware Spring ApplicationContext
.
Scopes a single bean definition to the lifecycle of a HTTP Session
. Only valid in the context of a web-aware Spring ApplicationContext
.
Scopes a single bean definition to the lifecycle of a global HTTP Session
. Typically only valid when used in a portlet context. Only valid in the context of a web-aware Spring ApplicationContext
.