In our JSF 2, spring 3 web application we have the following sets of entries in the web.xml to integrate spring and JSF
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/config/spring/applicationContext.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
And it works!
However, after going through quiet a few JSF & spring tutorials I see the need to define a RequestContextListener in addition to the ContextLoaderListener.
We have both request scope and session scope beans in our application.
Are both listeners mandatory? What is the consequence of not defining the RequestContextListener?
both are not mandatory, only the ContextLoaderListener
see
http://static.springsource.org/spring/docs/3.0.x/reference/web-integration.html
and
http://forum.springsource.org/showthread.php?t=81382
the RequestContextListener seems to be mandatory for Facelets
see http://static.springsource.org/spring/docs/3.0.x/api/org/springframework/web/context/request/RequestContextListener.html
This listener is mainly for use with third-party servlets, e.g. the JSF FacesServlet.
Related
I'm using Spring, but not SpringMVC in a web applcaition and gotta initialize Spring Application via web.xml
I have the standard web-project structure:
WEB-INF/applicationContext.xml
WEB-INF/web.xml
web.xml is currently contains:
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/applicationContext.xml</param-value>
</context-param>
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
But my question was caused that any listener should be bound to a servlet. In my case I don't use dispatcherServlet. How to load spring WebApplicationContext, all spring beans, etc in that case? What do I write in web.xml?
A ContextLoaderListener initializes a WebApplicationContext and stores it in the ServletContext attributes under the name referenced by WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE.
You can retrieve it that way.
servletContext.getAttribute(WebApplicationContext.ROOT_WEB_APPLICATION_CONTEXT_ATTRIBUTE);
anywhere you have access to the ServletContext, after the ContextLoaderListener has finished executing.
As suggested by M.Deinum in the comments, this is such a popular use case that Spring has its own utility to do it:WebApplicationContextUtils.getRequiredWebApplicationContext(ServletContext).
You don't need to change anything in your web.xml.
In a typical Spring MVC project there two "containers": One created by ContextLoaderListener and the other created by DispatchServlet.
I want to know, are these really two IoC container instance?( I see two bean config files, one is root-context.xml the other is servlet-context.xml)
If there are 2 containers, then what's the relationship?
Can the beans declared in one container be used in the other?
From the Spring Official Website:
The interface org.springframework.context.ApplicationContext
represents the Spring IoC container and is responsible for
instantiating, configuring, and assembling the aforementioned beans.
The container gets its instructions on what objects to instantiate,
configure, and assemble by reading configuration metadata. The
configuration metadata is represented in XML, Java annotations, or
Java code.
Again from official Doc:
In the Web MVC framework, each DispatcherServlet has its own
WebApplicationContext, which inherits all the beans already defined in
the root WebApplicationContext. These inherited beans can be
overridden in the servlet-specific scope, and you can define new
scope-specific beans local to a given Servlet instance.
Now coming to your Question, as is stated here:
In Spring Web Applications, there are two types of container, each of
which is configured and initialized differently. One is the
“Application Context” and the other is the “Web Application Context”.
Lets first talk about the “Application Context”. Application Context
is the container initialized by a ContextLoaderListener or
ContextLoaderServlet defined in the web.xml and the configuration
would look something like this:
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:*-context.xml</param-value>
</context-param>
In the above configuration, I am asking spring to load all files from
the classpath that match *-context.xml and create an Application
Context from it. This context might, for instance, contain components
such as middle-tier transactional services, data access objects, or
other objects that you might want to use (and re-use) across the
application. There will be one application context per application.
The other context is the “WebApplicationContext” which is the child
context of the application context. Each DispatcherServlet defined in
a Spring web application will have an associated
WebApplicationContext. The initialization of the WebApplicationContext
happens like this:
<servlet>
<servlet-name>platform-services</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:platform-services-servlet.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
You provide the name of the spring configuration file as a servlet
initialization parameter. What is important to remember here is that
the name of the XML must be of the form -servlet. xml.
In this example, the name of the servlet is platform-services
therefore the name of our XML must be platform-service-servlet.xml.
Whatever beans are available in the ApplicationContext can be referred
to from each WebApplicationContext. It is a best practice to keep a
clear separation between middle-tier services such as business logic
components and data access classes (that are typically defined in the
ApplicationContext) and web- related components such as controllers
and view resolvers (that are defined in the WebApplicationContext per
Dispatcher Servlet).
Check these links
Difference between applicationContext.xml and spring-servlet.xml in Spring Framework
http://static.springsource.org/spring/docs/3.2.x/spring-framework-reference/html/beans.html#beans-basics
There aren't two separate containers created. Typically, you want spring to instantiate the object declared in the servlet-context.xml when the object is required. So, you map the servlet-context.xml configuration file to the Dispatcher Servlet i.e. you want to initialize the object when a request hits the dispatcher servlet.
<servlet>
<servlet-name>appServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/appServlet/servlet-context.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
Where as, if you want to initialize the object and perform action when the context is being loaded you would declare the configuration file with in the context-param tags of your deployment descriptor.
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/root-context.xml</param-value>
</context-param>
You could test this out by writing by declaring separate beans in the servlet-context.xml and root-context.xml and then, autowiring them in a custom Context Loader Listener class. You would find only the root-context instances are initialized and servlet-context beans are null.
ApplicationContext a registry of components (beans).
ApplicationContext defines the beans that are shared among all the servlets i.e. root context configuration for every web application.
spring*-servlet.xml defines the beans that are related WebApplicationContexts here DispatcherServlet.
Spring container can have either single or multiple WebApplicationContexts.
Spring MVC have atleast 2 container -
Application Context declared by
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring/root-context.xml</param-value>
</context-param>
Servlet context declared by -
<servlet>
<servlet-name>appServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>servlet-context.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
And a web application can define any number of DispatcherServlet's. Each servlet will operate in its own namespace, loading its own application context with mappings, handlers, etc. Only the root application context as loaded by ContextLoaderListener, if any, will be shared. Thus can have any number of child containers.
I have read some tutorials about using spring, and I've seen they speak about "spring-config.xml", but when I create a project I don't have that file, I have "application-config.xml", are they the same? Is the former the updated version of the latter? I am using Eclipse as IDE
The Spring Context only defines the concept of creating a Spring configuration where you will define spring components (beans, services, etc)
The XML itself can be named whatever you want, but in the web.xml file, you have to pass the xml name you choose to the spring context listener
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/thisXMLhaTheBestNameEver.xml</param-value>
</context-param>
<listener>
<listener-class>
org.springframework.web.context.ContextLoaderListener
</listener-class>
</listener>
I am working on a Spring application. I started from creating a small java app using spring. Later, it became necessary to add a web interface. I decided to use Spring MVC. Now I am confused. In my web.xml I have
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/mvc-dispatcher-servlet.xml,
/WEB-INF/applicationContext.xml
</param-value>
</context-param>
where mvc-dispacher-servlet.xml contains beans necessary for web logic while applicationContext.xml contains beans performing some specific operations. My question is: Are beans in these files going to be aware of each other? Is it going to be a one big container which includes beans from both config files? or these containers are separate?
Yes it will be in one context which will be loaded from the web application context. Its the same as you would do when using the application context and passing in multiple files to it.
I am deploying Portlets on Liferay 5.2.3 on Tomcat 6. I get this error only for one of the portlet.
java.lang.IllegalStateException: Root context attribute is not of type WebApplicationContext
I did some research and found out that Spring was instantiating a portlet application context when it need a web one. But in my web.xml I am only defining contextLoaderListner
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
And to top it off, if a different *.jar file was being looked up by Spring, then why would my other portlets get deployed except one?
After couple of redeployments I get that to a fix. Can someone put some light on?
The root cause seems to be a static variable in the portal/application server "hanging onto" an instance of a class from the portlet. Two common culprits are log4j and java logging, both of which are commonly used by application containters.
See log4j and the thread context classloader and http://logback.qos.ch/manual/loggingSeparation.html for more discussion of loggers. The suggestion is to use SLF4J with logback OR to be sure to put log4j.jar in your WAR file so it is in the right classloader (although some containers will thwart this solution).
Also, some other class that is present in the container may be the cause. Logging is just a common problem.
Sounds like you are not defining the contextConfigLocation? in web.xml you should also have something like this in addition to the contextLoaderListener:
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/applicationContext.xml
</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
Where applicationContext.xml is a normal config file for a webapp.
You should also have this in your web.xml if using spring portlet MVC:
<servlet>
<servlet-name>ViewRendererServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.ViewRendererServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ViewRendererServlet</servlet-name>
<url-pattern>/WEB-INF/servlet/view</url-pattern>
</servlet-mapping>
In your portlet.xml I guess you have something like this to specify your portlets:
<portlet>
<portlet-name>sample</portlet-name>
<portlet-class>org.springframework.web.portlet.DispatcherPortlet</portlet-class>
<supports>
<mime-type>text/html</mime-type>
<portlet-mode>view</portlet-mode>
</supports>
<portlet-info>
<title>Sample Portlet</title>
</portlet-info>
</portlet>
If you haven't already, see the spring portlet mvc reference documentation
Hope it helps.