COME BACK

I am going to come back to my blog updating after two months’ silence.
And I changed my platform from windows to macOS.
I will focus more on technique skills in coding and talk more on what I faced during coding.
What’s more, I will update some articles about my thoughts & my values during life growing.

Thank you for your coming!

完全树的结点数n = 2^h - 1
亦有 结点数n = 2*底层结点数 - 1
注：底层结点数x = 2^(h - 1)

堆中i结点的子树大小至多为2n/3的证明

问题：在任一含n个元素的堆中，至多有ceiling(n/(2^(h+1)))个高度为h的节点。

一直搞不明白两者的区别。
如果使用了SpringMVC，事实上，bean的配置完全可以在xxx-servlet.xml中进行配置。为什么需要applicationContext.xml？一定必须？

First

因为直接使用了SpringMVC，所以之前一直不明白xxx-servlet.xml和applicationContext.xml是如何区别的，其实如果直接使用SpringMVC是可以不添加applicationContext.xml文件的。
使用applicationContext.xml文件时是需要在web.xml中添加listener的：

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

而这个一般是采用非spring mvc架构，如使用struts之类而又想引入spring才添加的，这个是用来加载Application Context。
如果直接采用SpringMVC，只需要把所有相关配置放到xxx-servlet.xml中就OK了。

Second

Spring lets you define multiple contexts in a parent-child hierarchy.

The applicationContext.xml defines the beans for the “root webapp context”, i.e. the context associated with the webapp.

The spring-servlet.xml (or whatever else you call it) defines the beans for one servlet’s app context. There can be many of these in a webapp, one per Spring servlet (e.g. spring1-servlet.xml for servlet spring1, spring2-servlet.xml for servlet spring2).

Beans in spring-servlet.xml can reference beans in applicationContext.xml, but not vice versa.

All Spring MVC controllers must go in the spring-servlet.xml context.

In most simple cases, the applicationContext.xml context is unnecessary. It is generally used to contain beans that are shared between all servlets in a webapp. If you only have one servlet, then there’s not really much point, unless you have a specific use for it.

More info: Source link

今天来说一下redirection与forward在Jsp中的一些细微差别