Spring MVC web app: application context starts twice
I'm working on a Spring MVC REST API. Everything works fine, which is great, but I noticed from the logs that every time I restart my app the applicationContext loads twice: once when tomcat loads the war file, and a second time when the web app is accessed for the first time by a client.
I'll give a few examples:
Right after I start the tomcat:
Apr 11, 2013 10:14:35 AM org.apache.catalina.core.StandardEngine start
INFO: Starting Servlet Engine: Apache Tomcat/6.0.32
Apr 11, 2013 10:14:36 AM org.apache.catalina.core.ApplicationContext log
INFO: Initializing Spring root WebApplicationContext
2013-04-11 10:14:36 INFO ContextLoader:273 - Root WebApplicationContext: initialization started
2013-04-11 10:14:36 INFO XmlWebApplicationContext:510 - Refreshing Root WebApplicationContext: startup date [Thu Apr 11 10:14:36 EDT 2013]; root of context hierarchy
2013-04-11 10:14:36 INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from ServletContext resource [/WEB-INF/mvc-dispatcher-servlet.xml]
2013-04-11 10:14:36 INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-general.xml]
2013-04-11 10:14:37 INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-db.xml]
2013-04-11 10:14:37 INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-security.xml]
2013-04-11 10:14:37 INFO SpringSecurityCoreVersion:33 - You are running with Spring Security Core 3.1.3.RELEASE
2013-04-11 10:14:37 INFO SecurityNamespaceHandler:59 - Spring Security 'config' module version is 3.1.3.RELEASE
...
And then at the moment I do the first API call:
INFO: Initializing Spring FrameworkServlet 'mvc-dispatcher'
2013-04-11 10:15:25 INFO DispatcherServlet:455 - FrameworkServlet 'mvc-dispatcher': initialization started
2013-04-11 10:15:25 INFO XmlWebApplicationContext:510 - Refreshing WebApplicationContext for namespace 'mvc-dispatcher-servlet': startup date [Thu Apr 11 10:15:25 EDT 2013]; parent: Root WebApplicationContext
2013-04-11 10:15:25 INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from ServletContext resource [/WEB-INF/mvc-dispatcher-servlet.xml]
2013-04-11 10:15:25 INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-general.xml]
2013-04-11 10:15:25 INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-db.xml]
2013-04-11 10:15:25 INFO XmlBeanDefinitionReader:315 - Loading XML bean definitions from class path resource [config-security.xml]
2013-04-11 10:15:25 INFO SecurityNamespaceHandler:59 - Spring Security 'config' module version is 3.1.3.RELEASE
Surely this can't be normal behavior?? My web.xml looks like this:
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<display-name>REST API</display-name>
<!-- Servlets -->
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>mvc-dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value>
</context-param>
<!-- filters -->
<filter>
<filter-name>httpMethodFilter</filter-name>
<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>httpMethodFilter</filter-name>
<servlet-name>mvc-dispatcher</servlet-name>
</filter-mapping>
<filter>
<filter-name>etagFilter</filter-name>
<filter-class>org.springframework.web.filter.ShallowEtagHeaderFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>etagFilter</filter-name>
<servlet-name>mvc-dispatcher</servlet-name>
</filter-mapping>
<filter>
<filter-name>CompressingFilter</filter-name>
<filter-class>com.planetj.servlet.filter.compression.CompressingFilter</filter-class>
<init-param>
<param-name>debug</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>statsEnabled</param-name>
<param-value>false</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CompressingFilter</filter-name>
<servlet-name>mvc-dispatcher</servlet-name>
</filter-mapping>
<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>
<!-- listeners -->
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
Answer
mvc-dispatcher is loading 2x because that is how you've defined it
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/mvc-dispatcher-servlet.xml</param-value>
</context-param>
and at
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>mvc-dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
the first approach is usually for loading something like a "global" or "root" context, where you might put all the bean/resources shared by multiple servlet contexts.
The second approach is usually for loading a specific servlet context. As the first answer in this post points out, it uses naming convention to find the mvc-dispatcher config file, so you don't need to explicitly define it.
Do you have everything defined in mvc-dispatcher-servlet.xml? If so you can remove the
<context-param>
..
</context-param>
definition, otherwise you can (which I recommend for future maintainability) separate your configuration into multiple files. Then load shared beans/resource in something like a root-context.xml (via the first method), and each servlet specific config under servletname-servlet.xml for each servlet context.