Location of groovy based bean definition configuration in a Spring MVC application - spring

I have seen that Spring 4 has a feature to define / having a groovy file for bean definitions instead of an XML file. I already have a Spring MVC application with mvc-dispatcher-servlet.xml for my bean definitions. But I want to go with Groovy based bean definition for my Spring MVC application. But, I am not sure where to place the groovy file and where do I need to refer it/ configure it to Load the bean definitions properly. Can somebody help or provide refrence?

use the GroovyWebApplicationContext ,
Web.xml
<servlet>
<servlet-name>mvc-dispatcher</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<init-param>
<param-name>contextClass</param-name>
<param-value>
org.springframework.web.context.support.GroovyWebApplicationContext
</param-value>
</init-param>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:/spring/dispatcherServlet.groovy</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
this is not a full example, but it is a good start

Related

Difference between "dispatcherServlet" and "appServlet" in spring MVC

Difference between "dispatcherServlet" and "appServlet" in spring MVC. Can I get any samples or references?
Technically both are HttpServlet implementation to handle incoming requests. DispatcherServlet is Spring provided servlet implemenation having all essential features like exception handling ..
You have to just write your Request mappers ,it will handle all request.
AppServlet is nothing different, just your implementation for specific handling of requests.
Both will work in same way .If you dont have any specific handling than you can just go with Spring DispatcherServlet.
For example..
<servlet>
<servlet-name>DispatcherServlet</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<load-on-startup>1</load-on-startup>
<!-- Custom Servlet -->
<servlet>
<servlet-name>CustomServlet</servlet-name>
<servlet-class>org.abc.CustomServlet</servlet-class>
<init-param>
<param-name>debug</param-name>
<param-value>false</param-value>
</init-param>
<init-param>
<param-name>any-other-Parameter</param-name>
<param-value>false</param-value>
</init-param>
<servlet-mapping>
<servlet-name>DispatcherServlet</servlet-name>
<url-pattern>*.do</url-pattern>
<url-pattern>/myapp/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>CustomServlet</servlet-name>
<url-pattern>/myapp2/*</url-pattern>
</servlet-mapping>
For reference of DispatcherServlet you can see http://www.mkyong.com/spring-mvc/spring-mvc-hello-world-example/
to understand this, you can have a look on below configuration :
<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/servlet-context.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
In above configuration DispatcherServlet is the servlet class provided by spring framework.
The job of the DispatcherServlet is to 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.
while appServlet is the custom name given by you in your web.xml file.

application-config.xml vs mvc-config.xml in spring

Im a newbie to Spring and trying to understand the web.xml file.
I have created a new SPring MVC Maven project using STS,
I'm little bit confused between the application-config.xml vs mvc-config.xml file...
mvc-config.xml contains the servlet mappings but what information does the application-config file contains..
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring/application-config.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!--
- Servlet that dispatches request to registered handlers (Controller implementations).
-->
<servlet>
<servlet-name>dispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/mvc-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
Usually the mvc configuration(/WEB-INF/mvc-config.xml) contains the the beans that are needed by the controller layer (e.g. the controllers, view resolvers ...) The application configuration(classpath:spring/application-config.xml) is for the model layer (here you can define daos, services...)

Double (Scheduler) bean initialization

I have 2 contexts in my application, one is "spring" (Web+MVC), second is "rpc" (just RPC service). Both of them inherits configs from the "spring" directory (there are 4 files: app-config.xml, infrastructure-config.xml, integration-config.xml and security-config.xml).
The app-config.xml contains initialization of the Quartz Scheduler.
So, if I starts my application, there are two Quartz Scheduler threads and all scheduled services are invoked twice. Is that because I inheriting settings from app-confix.xml into both contexts ?
I thought that beans deffined in parent config are initialized only once and shared between context which inheriting that parent config.
Thanks for any advice :).
Example from my web.xml.
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring/*-config.xml
</param-value>
</context-param>
<servlet>
<servlet-name>rpc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>0</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>rpc</servlet-name>
<url-pattern>/rpc/*</url-pattern>
</servlet-mapping>
<servlet>
<servlet-name>spring</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>spring</servlet-name>
<url-pattern>/web/*</url-pattern>
</servlet-mapping>
In your configuration two independent contexts are getting created. Just the fact that they use the same files doesn't cause spring to create a common parent context.
What you need to do is setup a contextLoaderListener in the web.xml - give it the common config file and then exclude it from the servlets config. The Listener will create the root context and bind it to the servlet context - both the servlets will then link to that as the parent context.

spring 3 mvc multiple application context instances

here is my web.xml:
<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<!-- Enables clean URLs with JSP views e.g. /welcome instead of /app/welcome -->
<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>
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring/*.xml
</param-value>
</context-param>
<!-- Handles all requests into the application -->
<servlet>
<servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring/*.xml
</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<!-- Maps all /app requests to the DispatcherServlet for handling -->
<servlet-mapping>
<servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
Why there are two instances of application context created?
When I add a scheduled method with #Scheduled it is invoked twice, because of those two application contexts.
You are loading twice times the same spring config files. Of course you have two separate application contexts. At first I would rename the servlet name for the DispatcherServerlet to "spring3mvc". The servlet definition should look like this:
<servlet>
<servlet-name>spring3Mvc</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<load-on-startup>1</load-on-startup>
</servlet>
If you have it in this way, you should have a spring config file "spring3Mvc-servlet.xml" in your "WEB-INF" directory. Spring will find this file automatically because of the right naming convention. In this file you should just have the beans who are important for springMVC. It could look like this:
<context:component-scan base-package="org.company.gui.controller"/>
<bean id="jspViewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
<property name="prefix" value="/WEB-INF/jsp/"/>
<property name="suffix" value=".view.jsp"/>
</bean>
This should fix your problem.
I noticed that you have
<load-on-startup>1</load-on-startup>
in the following block
<servlet>
<servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring/*.xml
</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
try removing that... it worked for me
Do you have any other spring filters or jsp pages in your web.xml not shown in your code snippet?
I ask, to answer your question, because I believe this quote from Spring documentation could explain what might be happening...
"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 defined can be
overridden in the servlet-specific
scope, and new scope-specific beans
can be defined local to a given
servlet instance."
If you answered "yes" to my web.xml question, then my guess is that Spring instantiates a root WebApplicationContext when a spring filter is created (via ContextLoaderListener). So, this would happen BEFORE...
Then, when the DispatcherServlet is created, the "contextConfigLocation" refers to the same files (that is, the same bean names), so a new WebApplicationContext gets overridden bean names local to that servlet!
I wonder, even if you answered "no", whether this might still happen anyway. Since you set "contextConfigLocation" (used by the ContextLoaderListener) and "override" it in DispatcherServlet configuration; I assume Spring is not checking whether those configurations are using the same file set.
You can run these scenarios through a debugger and put breakpoints on WebApplicationContext methods to find out for sure.
Workaround:
To solve the problem, either:
1) make sure your 2 contextConfigLocations don't overlap in files they use
Or:
2) break out the Scheduling bean in its own xml file and make sure it's referred to by only one of the 2 contextConfigLocations

How to add a Filter in Spring (with BlazeDS)

I want to add a filter to map a specific path in URL.
My server side used Spring 2.5.x, BlazeDS (servlet) with TomCat server.
So, my web.xml file is composed like that :
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>
/WEB-INF/spring-main-config.xml
</param-value>
</context-param>
<filter>
<filter-name>FacebookOAuthFilter</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
<filter-name>FacebookOAuthFilter</filter-name>
<url-pattern>/fbauth</url-pattern>
</filter-mapping>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<!-- Spring MVC Servlet (that will route HTTP requests to BlazeDS) -->
<servlet>
<servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring-main-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
When I start my TomCat server, an exception is catched :
[BlazeDS][ERROR] [Configuration] MessageBroker failed to start: Exception: flex.messaging.config.ConfigurationException: MessageBroker already defined from MessageBrokerServlet with init parameter messageBrokerId = '_messageBroker'
at flex.messaging.MessageBroker.registerMessageBroker(MessageBroker.java:1916)
COuld you help me please ?
Thank you very much,
Anthony
I believe you are loading the incorrect configuration file here...
<servlet>
<servlet-name>Spring MVC Dispatcher Servlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/spring-main-config.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
you have alreaded loaded /WEB-INF/spring-main-config.xml in the first few lines of the file
http://www.springbyexample.org/examples/simple-flex-webapp.html
This isn't really a Flex or BlazeDS issue, it's a more basic mis-configuration of Spring.
You're configured two separate Spring app-contexts, both with the same set of bean definitions (/WEB-INF/spring-main-config.xml).
The app-context defined by the <context-param> is the app-context associated with the webapp. The app-context defined by the ` is associated with the servlet.
Since you've given the same beans file to both, it'll instantiate and initialize the same set of beans twice, and the second time seems to be failing because the MessageBroker has already been defined.
You either need to break up your bean definitions into two sets, or just remove the first one, and just use the servlet context.

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