Dynamic spring properties - spring

Hi guys is there any good examples of changing spring properties files content dynamically? I would really appreciate it if you could give me some example or link.
Thanks alot

I think you could use ReloadableResourceBundleMessageSource .It uses java.util.Properties instances as its internal data structure for messages.
Also , as the name suggests , this class supports reloading of properties files through the cacheSeconds setting, and also through programmatically clearing the properties cache. Note that since application servers do typically cache all files loaded from the classpath, you have to put properties files outside of your classpath (WEB-INF/classes) or it'll be cached and won't work.
References / examples / links
http://techdive.in/spring/spring-internationalization-i18n
http://www.jroller.com/raible/entry/spring_mvc_s_reloadableresourcebundlemessagesource

Actually, spring support ${variable} in configration file like below
<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>file:${XXX}/XXX.properties</value>
<value>file:${XXX}/YYY.properties</value>
</list>
</property>
</bean>

Related

Load multiple properties file using <util:properties> in spring 3

I want to load multiple properties files using <util:properties> tag in a spring 3 application.
I searched on the blogs, but cannot get the correct path to do this.
Hopefully somebody give me the answer to overcome this problem.
Actually <util:properties> is just convenient tag for org.springframework.beans.factory.config.PropertiesFactoryBean. And PropertiesFactoryBean does support multiple locations.
So it is possible to create bean with Properties this way:
<bean id="myProps" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
<property name="locations">
<list>
<value>classpath:myprops-common.properties</value>
<value>classpath:myprops-override.properties</value>
<value>classpath:some-more-props-here.properties</value>
</list>
</property>
</bean>
My solution
<context:property-placeholder location="classpath*:*.properties,file:/some/other/path/*.properties" />
util:properties seems to support only 1 properties file (reference). You might want to use the configuration suggested by #peperg.

Accessing properties from PropertyPlaceholderConfigurer with multiple property files

I am new to spring (3.1) and totally stumped by this problem.
I am trying to access a property value "schdestination" using a PropertyPlaceholderConfigurer that is defined in two property files (one overriding the other).
I want to use #Value to set a field in a class and i just can't find a way to do it without using another bean. Here is my spring XML snippet
<bean id="placeholderProperties" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>/WEB-INF/abc.properties</value>
<value>/WEB-INF/loc.abc.properties</value>
</list>
</property>
<property name="ignoreUnresolvablePlaceholders" value="true" />
<property name="order" value="1" />
</bean>
Any clues please?
#Value("${schdestination}")
private String destination;
should work.
The class that contains the #Value needs to be annotated with #Component and you need to have <context:component-scan/> in your applicationContext.xml.
Are you using it in your web app? That was my case. I was loading property files from application context and somehow they were not visible in the web app package - controllers to be precise. I had to re-declare them in servlet-context.xml, then they are visible and work just fine. I am really hoping somebody might shed some light what could be going on, or whether it is truly an issue to be fixed in Spring.

Spring multiple error messages

I suppose that everybody that uses spring, uses form binding and validation. And you all defined the messages to display on validation errors. I did it with this in my config:
<bean id="messageSource"
class="org.springframework.context.support.ResourceBundleMessageSource"
p:basename="messages" />
what will happen basically is that it will read messages.properties in my root folder of the project.
But I'd need to put messages in two separate files. Because one part of the app has to be standalone. I tried adding this just after the one above:
<bean id="messageSourceAssistenza"
class="org.springframework.context.support.ResourceBundleMessageSource"
p:basename = "com.mypackage.other.assistenzamessages.properties"
/>
but it can't resolve those messages at all. How to solve this?
You should be able to use ResourceBundleMessageSource.setBasenames that accepts array of base names:
Set an array of basenames, each
following ResourceBundle conventions:
essentially, a fully-qualified
classpath location. If it doesn't
contain a package qualifier (such as
org.mypackage), it will be resolved
from the classpath root.
The associated resource bundles will
be checked sequentially when resolving
a message code. Note that message
definitions in a previous resource
bundle will override ones in a later
bundle, due to the sequential lookup.
Sample configuration as follows:
<bean id="messageSource"
class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basenames">
<list>
<value>messages_1</value>
<value>messages_2</value>
...
<value>messages_n</value>
</list>
</property>
</bean>

Good example of Spring Configuration using java.util.prefs or Commons Configuration

One application I'm working on has several URLs and other information that is instance specific. The first pass uses a typical Spring PropertyPlaceholderConfigurer with a properties file:
<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="classpath:application.properties"/>
</bean>
The main issue with this is of course the property file is an artifact that must be checked in, and for starting a new instance would require updating that artifact. For a streamline deployment, I would like to have the ApplicationContext bootstrap itself based on database table(s). I have seen solutions like this forum post, does anyone here know of better tools or is this defacto approach to this problem? I would also like to be able to update/reload the settings at runtime using JMX or other facilities, but having to restart the app after changes to the database would still be a better solution to the current one.
The way we did it was to put some configuration information in the environment and then pull the relevant info from there.
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="searchSystemEnvironment" value="true" />
</bean>
If configuration changes then the app will need to be restarted. Can also put all the different configurations into the environment and nest the variables like the following:
<bean id="db" class="org.DataSource"
p:databaseServer="${${MODE}_DBSERVER}"
p:databaseName="${${MODE}_DBNAME}" />
where $MODE = dev, qa, etc.

external config based on context path

I would like to deploy multiple independent copies of a particular web-app on the same tomcat server under different context paths. Each web-app will need different configuration settings (database name, password, etc), but I would like to keep the wars exactly identical.
My plan was to have the app figure out its context path on startup, then read a specific .properties file outside of tomcat identified by the context path. For example, if a war was deployed to {tomcat path}/webapps/pineapple, then I would want to read /config/pineapple.properties
I've been trying to find a way to inject an instance of ServletContext via spring (3), but all the advice I've seen so far use the deprecated ServletContextFactoryBean.
Is there a better way to get the context path injected or better way to load external files based on the context path?
With the help of ServletContextAttributeFactoryBean and Spring EL, you can reference ServletContext init parameters (<context-param> in web.xml) like that:
#{contextAttributes.myKey}
This allows you to use PropertyPlaceHolderConfigurer and load property files from arbitrary, user-defined locations:
<bean
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="#{contextParameters.APP_HOME}/conf/app.properties"/>
</bean>
The corresponding definition of the ServletContext init parameter in Tomcat's context.xml:
<Parameter name="APP_HOME" value="file:/test" override="false"/>
Or in your app's web.xml:
<context-param>
<param-name>APP_HOME</param-name>
<param-value>file:/test</param-value>
</context-param>
This should be the solution.
<bean name="envConfig" class="EnvironmentConfiguration">
<property name="locations">
<list>
<value>file:///#{servletContext.contextPath}.properties</value>
</list>
</property>
<property name="ignoreUnresolvablePlaceholders" value="true" />
</bean>
Extend Propertyplaceholderconfigurer to use DB to pick up the values. Example here
Load the actual values of the settings (database name, password etc) to the db as part of seed data
When your web-app's app ctx is being initialized, the properties are resolved from the DB
This is the approach we have been following and works great. If you can switch to Spring 3.1 then it has support for Environment Profiles which may be useful for you.

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