How can I display a JBoss property in JSTL (without using Java)? - spring

I’m using JBoss 7.1.3 and Spring 3.2.11.RELEASE. I have this property defined in my $JBOSS_HOME/standalone/configuration/standalone.xml file
<system-properties>
<property name=“myProperty” value=“myValue”/>
…
In my JSP, through JSTL, is it possible to access this value without any additional code in a Java servlet? If I need to put something in a Spring XML application context file to accommodate this, that’s fine with me.

Assuming those are real system properties, just add a ServletContextListener to your application, and in its contextInitialized() method, store the system properties in the servlet context:
servletContext.setAttribute("systemProperties", System.getProperties());
Then, in any JSP:
<c:out value="${systemProperties.myProperty}"/>

Related

Binding datasource to application when using springBootApplication in Liberty?

When deploying "regular" web apps to Liberty, I was used to binding the global datasource configured in Liberty's server.xml to the individual application by using a child element within the element, like this:
<application context-root="helloApp" location="..." name="helloApp" type="war">
<application-bnd>
<data-source id="db2appDs" name="jdbc/datasource" binding-name="jdbc/theDB"/>
</application-bnd>
...
</application>
<dataSource id="db2ds" jndiName="jdbc/theDB" type="javax.sql.DataSource">
...
</dataSource>
When configuring my first Spring Boot application to deploy to Liberty, I am trying to use the new <springBootApplication> element for it - but I don't seem to be able to add a binding for the datasource I want to use the same way, as this element doesn't seem to support such a child. (It seems to want only <classloader> as a child).
I've seen people suggest I use an #Resource annotation that includes both application-local JDNI name and global JNDI name for the datasorce - but that defeats the purpose, since I don't want to know what the global name is until deploy time.
Is there another way to do this, like we used to before? Or are applications deployed through <springBootApplication> expected to know the global JNDI name of the datasource(s) they want?
Application-defined datasources are not supported for <springBootApplication/>’s. While your application may certainly access a Liberty datasource using its global JNDI name, you should configure the spring.datasource.jndi-name property within your Spring Boot application as described in section 29.1.3 of the Spring Boot features reference. For your example try spring.datasource.jndi-name=jdbc/theDB.

Spring customised PropertyPlaceholderConfigurer

I have config xml based spring application for which I have moved proprties required at start up time in database. It was very difficult to manage hundreds in property file and that is why database is introduced. To read properties a spring restful service is developed to return a map of all properties required at start up time.
I want to know how to replace properties reading from a map to spring context file e.g. ${config.service.url} should be polulated from a map read via web service.
One option I considered is to upgrade to Annotation based and start using MapPropertySource and Environment interface as environment.getRequiredProperty("config.service.url"). However upgrading to Annotation based is a big impact on project and is no at this time.
Second option that I am looking forward is to have a customised PropertyPlaceholderConfigurer.
Any pointer/help on this will be great.
Cheers,
Amber
You could define a PropertyPlaceholderConfigurer, but instead of specifying a file location, you can pass the properties directly as returned by your restful service.
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="properties" .../>
</bean>

Get config setting in custom taglib using Spring "context-property-placeholder"

I'm creating a custom taglib, and would like to use some config options that are loaded via the underlying Spring framework using:
<context:property-placeholder location="classpath:config.properties" />
How would I get access to these variables in my taglib?
Thanks,
James.
The JSP taglibs have nothing in common with the Spring context's lifecycle, they're managed by the servlet container. This can complicate things a bit, for example: inject-dependency-into-a-taglib-class, how-to-write-tag-in-my-spring-project.
Since you're only mentioning the need for contents of the properties file, you could use plain old java.util.ResourceBundle (or, if you need more flexibility, Apache Commons' org.apache.commons.configuration.PropertiesConfiguration).
(One could also argue that requiring access to configuration in your tags indicates a design problem...)

How to retrieve context parameters in Spring 3.1 xml context

It seems like there's been a few iterations of property support in spring it's hard to tell what's best practice and the manuals are written from the point of view of someone who is familiar with every other iteration. I feel like this should be a simple and common requirement but given how hard it's been please correct me if there's a more idiomatic way.
What I want is to pass an additional properties file to my spring web app based on a context property which the client is setting using a tomcat descriptor like so
<Context path="/foo" reloadable="true">
<Parameter name="foo.config" value="file:${catalina.base}/conf/foo.properties"/>
</Context>
In spring for the live profile I have this
<beans profile="live">
<context:property-placeholder location="classpath:timetabling.live.properties,${timetabling.config}"
ignore-resource-not-found="true" />
</beans>
So I'd assumed this doesn;t work because I'm trying to configure placeholder suppport with a placeholder. If I use a system property however then this works fine. I know that spring 3.1 has baked in support for system and environment properties so I guess my question is how can I augment this support with something context aware before the placeholder is resolved?
--Update--
looking at http://blog.springsource.org/2011/02/15/spring-3-1-m1-unified-property-management/ particularly at footnote 1, I would expect to have a DefaultWebEnvironment which should already have aceess to context init params. Now I am more confused, can someone provide me with a concrete example of context property retrieval? At this point I feel like I've read every javadoc available and they are just not helpful.
<context:property-placeholder /> sets up a PropertyPlaceholderConfigurer which reads from .properties, system properties and environment variables. A Tomcat context.xml however sets up a servlet context init parameter. So what you need is a ServletContextPropertyPlaceholderConfigurer.

How to configure JSF 2.0 application's project stage via JNDI in Tomcat

been struggling to find a way to configure Tomcat 7.0.11 so that my web application would use project stage setting from Tomcat's config. So far - no luck. The idea is to set this property in Tomcat server/host/application wide but not to set it in web.xml. Any ideas? I am using MyFaces JSF 2 implementation 2.0.5.
The specification says that the JSF implementation looks up the Project Stage using JNDI under java:comp/env/jsf/ProjectStage. If not found it uses the context parameter javax.faces.PROJECT_STAGE from your web.xml. This means that if defined/found on your Tomcat using JNDI, the value of preferred over the web.xml setting.
There are two things you can do:
Option 1: Overwrite the context parameter: This means that context parameter is set/overwritten using the Tomcat server.xml or context.xml. You need to put this in your <Context>-tag:
<Parameter name="javax.faces.PROJECT_STAGE" value="Production" override="false" />
Careful: override="false" here means that this parameter can NOT be overriden by the web.xml (not the other way around)!
Option 2: Configure a resource that can be found using JNDI: By using this that JSF implementation can resolve the project stage using the JNDI lookup.
<Environment name="jsf/ProjectStage" value="Production" type="java.lang.String" override="false"/>
You can also move this to the <GlobalResources>-tag in your server.xml. In this case you would need to reference this in your <Context>-tag by using <ResourceLink>-tag.

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