ContextLoaderListener初始化的前后文和DispatcherServlet初始化的上下文关系

从图中可以看出：

ContextLoaderListener初始化的上下文加载的Bean是对于整个应用程序共享的，不管是使用什么表现层技术，一般如DAO层、Service层Bean；

DispatcherServlet初始化的上下文加载的Bean是只对Spring Web MVC有效的Bean，如Controller、HandlerMapping、HandlerAdapter等等，该初始化上下文应该只加载Web相关组件。

如果分开配置，则web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app  version="3.1" xmlns="http://xmlns.jcp.org/xml/ns/javaee"  
                        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                        xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
                                            http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd">
        
     <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/applicationContext.xml</param-value>
        <!-- 默认是/WEB-INF/applicationContext.xml -->
     </context-param>
     
     <listener>
        <listener-class>
            org.springframework.web.context.ContextLoaderListener
        </listener-class>
     </listener>
  
    <servlet>
        <servlet-name>SpringMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/SpringMVC-servlet.xml</param-value>
            <!-- 默认是/WEB-INF/[servlet名字]-servlet.xml -->
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    
    <servlet-mapping>
        <servlet-name>SpringMVC</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
  
</web-app>

https://www.cnblogs.com/winkey4986/p/5280138.html