Why my applicationContext.xml is needed by DispatcherServlet?

isn't DispatcherServlet is responsible for managing the mvc-config only, and the ContextLoaderListener is responsible for applicationContext.xml

this was my old configuration for web.xml:

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">

  <!-- start up and shut down Spring's root WebApplicationContext (Interface to provide configuration for a web application) -->
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

  <!-- Central dispatcher for HTTP request handlers/controllers: take an incoming URI and find the right combination of handlers (generally methods on Controller classes) 
  and views (generally JSPs) that combine to form the page or resource that's supposed to be found at that location. -->
  <servlet>
    <servlet-name>p</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>
            /WEB-INF/spring/webmvc-config.xml       
            </param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>

  <servlet-mapping>
    <servlet-name>p</servlet-name>
    <url-pattern>/p/*</url-pattern>
  </servlet-mapping>

  <!-- allows one to specify a character encoding for requests. 
  This is useful because current browsers typically do not set a character encoding even if specified in the HTML page or form -->
  <filter>
    <filter-name>encoding-filter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
      <param-name>encoding</param-name>
      <param-value>utf-8</param-value>
    </init-param>
    <init-param>
      <param-name>forceEncoding</param-name>
      <param-value>true</param-value>
    </init-param>
  </filter>

  <filter-mapping>
    <filter-name>encoding-filter</filter-name>
    <url-pattern>/*</url-pattern>
    <dispatcher>REQUEST</dispatcher>
    <dispatcher>FORWARD</dispatcher>
  </filter-mapping>

  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>
      /WEB-INF/spring/applicationContext.xml
    </param-value>
  </context-param>

  <!--  
  <filter>
  <filter-name>springSecurityFilterChain</filter-name> 
  <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> 
  </filter>

 <filter-mapping>
  <filter-name>springSecurityFilterChain</filter-name> 
  <url-pattern>/*</url-pattern> 
  </filter-mapping>  
  -->


  <!-- Based on the popular and very useful mod_rewrite for apache, UrlRewriteFilter is a Java Web Filter for any J2EE
       compliant web application server (such as Resin or Tomcat), which allows you to rewrite URLs before they get to your
       code. It is a very powerful tool just like Apache's mod_rewrite. -->
  <filter>
  <filter-name>UrlRewriteFilter</filter-name> 
  <filter-class>org.tuckey.web.filters.urlrewrite.UrlRewriteFilter</filter-class>
  </filter>

  <filter-mapping>
  <filter-name>UrlRewriteFilter</filter-name> 
  <url-pattern>/*</url-pattern> 
  </filter-mapping>


</web-app>

but with this config, i got the following exception:

org.hibernate.HibernateException: No Hibernate Session bound to thread, and configuration does not allow creation of non-transactional one here
    org.springframework.orm.hibernate3.SpringSessionContext.currentSession(SpringSessionContext.java:63)
    org.hibernate.impl.SessionFactoryImpl.getCurrentSession(SessionFactoryImpl.java:574)
    com.spring.sample.dao.impl.PersonDaoImpl.getCurrentSession(PersonDaoImpl.java:30)
    com.spring.sample.dao.impl.PersonDaoImpl.getAllPersons(PersonDaoImpl.java:69)
    com.spring.sample.controller.PersonsController.get(PersonsController.java:34)
    sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    java.lang.reflect.Method.invoke(Method.java:597)
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.doInvokeMethod(HandlerMethodInvoker.java:710)
    org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:167)
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:414)
    org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:402)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:771)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:716)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:647)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:552)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:70)
    org.tuckey.web.filters.urlrewrite.NormalRewrittenUrl.doRewrite(NormalRewrittenUrl.java:195)
    org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:159)
    org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:141)
    org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:90)
    org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:417)
    org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)

webmvc-config.xml:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/s开发者_Go百科pring-mvc-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">

    <!-- webmvc-config.xml: is for web configuration, and it's loaded with Dispatacher Servlet -->

    <context:component-scan base-package="com.spring.sample" />

    <!-- - It declares explicit support for annotation-driven MVC controllers (i.e. @RequestMapping, @Controller, etc).
         - configures support for new Spring MVC features such as declarative validation with @Valid, HTTP message conversion with @RequestBody/@ResponseBody.
         - supports Spring Jackson JSON.  -->
    <mvc:annotation-driven />

    <!-- Changes the locale when a 'lang' request parameter is sent; e.g. /?lang=ar -->
    <mvc:interceptors>
        <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor"
            p:paramName="lang" />
    </mvc:interceptors>

    <!-- uses a locale attribute in the user's session  -->
    <bean id="localeResolver"
        class="org.springframework.web.servlet.i18n.SessionLocaleResolver" />

        <!-- - translates from view name to view class.
             - makes views avaiable to controllers, when controller return a view name, the view name is rendered. -->
    <bean class="org.springframework.web.servlet.view.BeanNameViewResolver" /> 

        <!-- viewResolver for jsp -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/views/"/>
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

but this exception was solved after adding applicationContext.xml to DispatcherServlet in my web.xml, any ideas why ?

I guess you use @Transactional. If so, note that the effect of <tx:annotation-driven /> is limited to the context where it is declared.

So, if you have any beans with @Transactional declared in webmvc-config.xml, you should also add <tx:annotation-driven /> there. If <tx:annotation-driven /> is specified in applicationContext.xml only, it can result in behaviour you describe.

I think it has to do with each dispatch servlet having it's own context, look at this blog

http://www.dotkam.com/2008/07/09/spring-web-application-context-visibility/

I solved this problem by doing some thing like this, I use listener to load all my context files like this

<context-param>
  <param-name>contextConfigLocation</param-name>
  <param-value>
      /WEB-INF/spring/applicationContext.xml, /WEB-INF/spring/applicationContext-MVC.xml
    </param-value>
  </context-param>

I created a dummy context config with no configuration defined in it, I had to do this since dispatch servlet complains of not having context configuration

 <init-param>
  <param-name>contextConfigLocation</param-name>
  <param-value>
        /WEB-INF/spring/dummy-config.xml       
        </param-value>
   </init-param>