<context:property-placeholder

        ignore-unresolvable="true" location="classpath*:/application.properties" />

<!-- springmvc配置开始 -->
<servlet>

    <servlet-name>springmvc</servlet-name>

    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

    <!-- 可以自定义servlet.xml配置文件的位置和名称，默认为WEB-INF目录下，名称为[<servlet-name>]-servlet.xml，如spring-servlet.xml

    <init-param>

        <param-name>contextConfigLocation</param-name>

        <param-value>/WEB-INF/spring-servlet.xml</param-value>

    </init-param>

    -->

    <load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

    <servlet-name>springmvc</servlet-name>

    <url-pattern>*.do</url-pattern>

</servlet-mapping>

<!-- springmvc配置结束 -->

<!-- Spring配置开始 --> 
<listener> 
   <listenerclass>org.springframework.web.context.ContextLoaderListener</listener-class> 
</listener> 
<!-- 指定Spring Bean的配置文件所在目录。默认配置在WEB-INF目录下 --> 
<context-param> 
   <param-name>contextConfigLocation</param-name> 
   <param-value>classpath:config/applicationContext.xml</param-value> 
</context-param>

<!-- Spring配置结束 -->

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

spring允许你定义多个上下文在父子继承关系中

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

applicationContext.xml文件是为了"根webapp应用上下文"定义bean,也就是说它的上下文是和webapp相关联的

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, 
spring-servlet.xml文件(或是其他的你习惯的称呼)是为了一个servlet应用上下文定义bean.在一个webapp中可以有多个此配置文件,
one per Spring servlet (e.g. spring1-servlet.xml for servlet spring1, spring2-servlet.xml for servlet spring2).

每一个配置对应一个spring的servlelt(例如: 名为spring1的servlet拥有配置文件spring1-servlet.xml, 名为spring2的servlet拥有配置文件spring2-servlet.xml).

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

在spring-servlet.xml中定义的bean可以直接引用在applicationContext.xml中定义的bean, 但是反过来不可以.

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

所有springmvc的Controller必须在spring-servlet.xml对应的上下文中运行.

In most simple cases, the applicationContext.xml context is unnecessary. It is generally used to contain beans that are shared between all servlets
在大多数简单的情况下, applicationContext.xml对应的上下文并不必须.它通常用来包含那些bean用来在webapp中所有servlet之间共享.
in a webapp. If you only have one servlet, then there's not really much point, unless you have a specific use for it.
如果你只有一个servlet, 那么实际没有什么必要定义applicationContext.xml, 除非你有特别应用.