Webapplicationcontext initialization in Spring Contextloaderlistener

<span id="Label3"></p><p><p>In spring and structs2 integration, you need to set up a listener in the Web. XML file, as follows</p></p><p><p></p></p><pre class="brush:xml;toolbar:false"><pre class="brush:xml;toolbar:false"><listener> <listener-class> Org.springframework.web.context.ContextLoaderListener < ;/listener-class> </listener></pre></pre><p><p>Contextloaderlistener is initialized when the Web container is initialized, and then initializes the Webapplicationcontext Work. Let's take a look at the key code for Contextloaderlistener:</p></p><p><p></p></p><pre class="brush:java;toolbar:false"><pre class="brush:java;toolbar:false">public void contextinitialized (servletcontextevent event) {this.contextloader = Createcontextloader ();        if (this.contextloader = = Null) {this.contextloader = this;    } this.contextLoader.initWebApplicationContext (event.getservletcontext ()); }</pre></pre><p><p>This code implements the Webapplicationcontext initialization, calling the Contextloader Initwebapplicationcontext method in the last line of the code, Let's take a look at the key code of Contextloader's Initwebapplicationcontext method:</p></p><pre class="brush:java;toolbar:false">    public webapplicationcontext initwebapplicationcontext (ServletContext  Servletcontext)  {        if  (servletcontext.getattribute ( Webapplicationcontext.root_web_application_context_attribute)  != null)  {             throw new illegalstateexception (                      " cannot initialize context because there is already a root  application context present -  " +                      "check whether you have  multiple contextloader* definitions in your web.xml! ");         } &nBsp;      log logger = logfactory.getlog (ContextLoader.class);         servletcontext.log ("initializing spring root  Webapplicationcontext ");        if  (logger.isInfoEnabled ())   {            logger.info ("Root  webapplicationcontext: initialization started ");         }         long starttime = system.currenttimemillis ();         try {             // store context in local instance variable, to  guarantee that            // it  is available on servletcontext shutdown.            if  ( This.context == null)  {                 this.context = createwebapplicationcontext (servletContext);             }</pre><p><p> The last line, and the Createwebapplicationcontext method is called, Let's look at the code for this method: </p> </p><pre class="brush:java;toolbar:false">    protected webapplicationcontext createwebapplicationcontext (ServletContext  sc)  {        Class<?> contextClass =  Determinecontextclass (sc);        if  (! ConfigurableWebApplicationContext.class.isAssignableFrom (CONTEXTCLASS))  {             throw new applicationcontextexception ("Custom context  class [" + contextclass.getname ()  +                      "] is not of type  [" + configurablewebapplicationcontext.class.getname ()  + "] ");         }        return  ( Configurablewebapplicationcontext)  beanutils.instantiateclasS (contextclass);     } </pre><p><p>The code shows that you return a configurablewebapplicationcontext here, and then take a look at the most critical code in the Contextloader initwebapplicationcontext method:</p></p><pre class="brush:java;toolbar:false"><pre class="brush:java;toolbar:false">Servletcontext.setattribute (webapplicationcontext.root_web_application_context_attribute, this.context);</pre></pre><p><p>Here the context is deposited into the servletcontext, so later to use the Webapplicationcontext can be removed from the Servletcontext.</p></p><p><p>This article is from the "flying fish technology" blog, Please be sure to keep this source http://flyingfish.blog.51cto.com/9580339/1681334</p></p><p><p>Webapplicationcontext initialization in Spring Contextloaderlistener</p></p></span>