Before post this Question, I google to get Properties from Spring project(Its NOT web-based project). I am confused as every one are talking about application-context.xml and have configuration like
However, I am working on normal Java Project with Spring(NO Web-app and stuff like that). But I would like to get some common properties from properties file and that needs to be used in JAVA file. How can achieve this by using Spring/Spring Annotations?
Where I should configure myprops.properties file under my project and how to invoke through spring?
My understanding is application-context.xml is used ONLY for web based projects. If not, how should I configure this application-context.xml as I do NOT have web.xml to define the application-context.xml
You can create an XML based application context like:
ApplicationContext ctx = new ClassPathXmlApplicationContext("conf/appContext.xml");
if the xml file is located on your class path. Alternatively, you can use a file on the file system:
ApplicationContext ctx = new FileSystemXmlApplicationContext("conf/appContext.xml");
More information is available in the Spring reference docs. You should also register a shutdown hook to ensure graceful shutdown:
ctx.registerShutdownHook();
Next, you can use the PropertyPlaceHolderConfigurer to extract the properties from a '.properties' file and inject them into your beans:
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations" value="classpath:com/foo/jdbc.properties"/>
</bean>
<bean id="dataSource" destroy-method="close" class="org.apache.commons.dbcp.BasicDataSource">
<property name="driverClassName" value="${jdbc.driverClassName}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</bean>
Lastly, if you prefer annotation based config, you can use the #Value annotation to inject properties into you beans:
#Component
public class SomeBean {
#Value("${jdbc.url}")
private String jdbcUrl;
}
As of Spring 4, you can use the #PropertySource annotation in a Spring #Configuration class:
#Configuration
#PropertySource("application.properties")
public class ApplicationConfig {
// more config ...
}
If you would like to have your config outside of your classpath, you can use the file: prefix:
#PropertySource("file:/path/to/application.properties")
Alternatively, you can use an environmental variable to define the file
#PropertySource("file:${APP_PROPERTIES}")
Where APP_PROPERTIES is an environmental variable that has the value of the location of the property file, e.g. /path/to/application.properties.
Please read my blog post Spring #PropertySource for more information about #PropertySource, its usage, how property values can be overridden and how optional property sources can be specified.
You don't have to use Spring.
You can read with plain java like this:
Properties properties = new Properties();
properties.load(Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName));
Can you figure out how your project will be used in the whole app? If your project is used as a build path for a web app and the configuration in your project is achieved through spring annotations, so no doubt you are puzzled about how to add an application.xml file. My suggest is you have to announce the guys who will use your project, tell them what you need and you just need to add #Value("${valuename}") in your code.
Create new property file inside your src/main/resources/ directory and file extension must be .properties e.g. db.properties
Write following context properties in your spring xml configuration file:
<context:property-placeholder location="db.properties"/>
Usage: ${property-key}
Related
I'm writing a WebApp back-end with spring in java. in the code there are a lot of magic numbers. is there a way to put this in a config in such a way that any changes in this config will be put in effect without restarting the entire app?
When java process start it loads spring context, once spring context is loaded it only reads properties file once so if you are changing any property you have to restart your app thats good to have way.
OR you can replace java.util.Properties with a PropertiesConfiguration from the Apache Commons Configuration project. It supports automatic reloading, either by detecting when the file changes, or by triggering through JMX.
one more alternate way is to keep all your prop variables in database and refresh your reference cache periodically that way you don't have to restart your app and can change properties on-fly from database.
You can call the configuration file through the below steps:
Use the #Configuration annotation for the class which calls the
config file.
Another annotation to be declared above the class for defining the path to the config file #PropertySource({"URL/PATH_OF_THE_CONFIG_FILE"})
#Value("${PROPERTY_KEY}") annotation above a variable where the value corresponding to the property_key needs to be assigned.
The the following bean in the same configuration invoking class.
#Bean
public static PropertySourcesPlaceholderConfigurer propertyConfigInDev() {
return new PropertySourcesPlaceholderConfigurer();
}
Make sure the #ComponentScan covers the folder where the config file is placed
Here is the way you can configure it
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xsi:schemalocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<!--To load properties file -->
<bean id="placeholderConfig" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="classpath:META-INF/*-config.properties">
</property></bean>
<bean id="createCustomer" class="com.example.Customer">
<property name="propertyToInject" value="${example.propertyNameUnderPropertyFile}">
</beans>
You can also refer it in java file straight away
public class Customer {
#Value("${example.propertyNameUnderPropertyFile}")
private String attr;
}
I am using Spring version 4.0.6.RELEASE and am trying to have spring read from a properties file and use one of the resolved properties to provide a location to another properties file. My spring.xml file has the following:
<bean id="applicationProperties" class="org.springframework.beans.factory.config.PropertiesFactoryBean">
<property name="locations">
<list>
<value>classpath:application.properties</value>
<value>classpath:version.properties</value>
<!- The below file contains the another file location -->
<value>file:${catalina.base}/conf/instance.properties</value>
<value>${another.file.location}</value>
</list>
</property>
<property name="ignoreResourceNotFound" value="true"/>
</bean>
instance.properties contains:
account.id=BlahBlahBlah
another.file.location=file:/Users/beardman/.myapp/local.properties
and /Users/beardman/.myapp/local.properties contains:
magic.number=3
database.endpoint=blah
I keep getting the following warning:
WARN [main] o.s.b.f.c.PropertyPlaceholderConfigurer Could not load properties from ServletContext resource [/${another.file.location}]: Could not open ServletContext resource [/${another.file.location}]
When debugging my code, I can see that the account.id was injected correctly, but I can never get the magic.number or database.endpoint to show up. How can I get spring to use the resolved property from the instance.properties file as the value for the another.file.location?
EDIT: Added property file contents
Spring by default replaces property placeholders with system properties. Since you want to use properties defined in an external file as well, you need to create a PropertyPlaceholderConfigurer
This tag is the shorthand, but you can define PropertyPlaceholderConfigurer as a bean if you need more control. Add this before your applicationProperties bean
<context:property-placeholder location="file:${catalina.base}/conf/instance.properties"/>
Note that properties in the file will override system properties in the default mode. You can specify that system properties are checked first by adding the attribute systemPropertiesMode="override" to the property-placeholder element
I have a jar containing a spring configuration. I am retrieving some JNDI variables to configure web service addresses inside the jar. Now, I am using the same jar in a Spring Batch and I would like to use the same spring configuration file.
My problem is that I am passing the web service addresses as system properties to my batch with the
java -DmyFoo=bar
Using this
<context:property-placeholder system-properties-mode="OVERRIDE" ignore-unresolvable="true" />
I can get my variables as #Value("myFoo")
So my question is: is there any way to be able to get my JNDI variables in my property placeholder? Or be able to get them as JNDI and then expose them in a property placeholder?
What I want to be able to do is replace this
<bean id="MBean" class="com.xxx.utils.ActivationMBean">
<property name="makeCall">
<jee:jndi-lookup jndi-name="semantic.activation" />
</property>
</bean>
By this
<bean id="MBean" class="com.xxx.utils.ActivationMBean">
<property name="makeCall" value="${semantic.activation}" />
</bean>
When using <context:property-placeholder /> a PropertySourcesPlaceholderConfigurer is registered. (That is when you are on Spring 3.1 or later and are using the xsd without version or a version > 3.0). The property-source abstraction has been added in Spring 3.1.
The PropertySourcesPlaceholderConfigurer uses the configured PropertySources to obtain values for placeholders. The PropertySources consulted depends on the environment, web or non-web, and the amount of #PropertySource annotations or loaded property files through the location attribute of the <context:property-placeholder /> elements.
For the StandardServletEnvironment (web) the PropertySources are consulted in the following order.
ServletContext init-params
ServletContext context-params
JndiPropertySource
System Properties
System Environment
For the StandardEnvironment (non-web) the PropertySources are consulted in the following order.
System Properties
System Environment
Depending on the setting of the localOverride property properties loaded from properties files are added to the top (true) or to the bottom (false) of the list of PropertySources to consult.
Given the following bean definition.
<bean id="MBean" class="com.xxx.utils.ActivationMBean">
<property name="makeCall" value="${semantic.activation}" />
</bean>
In a web environment the placeholder ${semantic.activation} is being resolved first against the JNDI tree if that isn't found it will fallback to the System Properties. For a non-web no JNDI lookup is attempted and properties specified by -D or in the environment are consulted.
I finally found a trick that makes what I need:
<bean id="MBean" class="com.xxx.utils.ActivationMBean">
<property name="makeCall">
<jee:jndi-lookup jndi-name="semantic.activation" default-value="${semantic.activation}" />
</property>
</bean>
It can't be used with the #Value annotation but if we are using JNDI it will take it and not it will fall back to the property. If none is defined it will fail to start and that is what I wanted.
when I have a bean
<bean name="myBean" class="mypackage.myBean">
<property name="otherBean" ref="otherBeanRef" />
</bean>
and I click on otherBeanRef I'm redirected to definition of otherBeanRef, however this only works if its in the same file.
how to configure spring ide to also support other spring files?
You need to add both files to the Spring Spring Config File Set.
Spring Explorer/Properties/Config Sets
I am trying to find the best way to pass complex configurations in a Spring webapp running in Tomcat. Currently I use JNDI to pass data sources and strings from the Tomcat context into the webapp, and this works well.
But, lets say I need to select the implementation of a notification service. There is no way that Spring can conditionally select which bean to instantiate (although in the past I have used a JNDI string to import a predefined configuration of beans by setting contextConfigLocation).
I've also seen many webapps which supply a configuration tool which will create a custom WAR file. In my opinion this is bad form, if for no other reason than it prevents the redeployment of WARs from upstream without many checks to ensure all the configuration has been re-applied.
Ideally I would be able to supply a Spring XML file which existed on the filesystem, outside of the webapp. But, the spring import directive does not seem to resolve ${} variables, making it impossible to supply customisations.
Are there any techniques I can employ here to properly separate complex configuration from the webapp?
If I have a specific set of beans that I'd like to configure, and this configuration must be separated from the WAR file, I usually do the following:
In applicationContext.xml:
<!-- here you have a configurer based on a *.properties file -->
<bean id="configurer"
class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="file://${configDir}/configuration.properties"/>
<property name="ignoreResourceNotFound" value="false" />
<property name="ignoreUnresolvablePlaceholders" value="false" />
<property name="searchSystemEnvironment" value="false" />
</bean>
<!-- this is how you can use configuration properties -->
<bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
<property name="host" value="${smtp.host}"/>
</bean>
In configuration.properties:
smtp.host=smtp.your-isp.com
You also need to start Tomcat with -DconfigDir=/path/to/configuration/directory
If you are using Spring 3, you can take advantage of the Spring Expression Language. Let's say you have two applications app1.war and app2.war and they require a properties file named config.properties. The applications will be deployed with context paths /app1 and /app2.
Create two directories app1 and app2 in a common directory, eg. C:\myConfig\app1 and C:\myConfig\app2.
Put config.properties inside app1 and another config.properties inside app2.
Then create a file ${CATALINA_HOME}/conf/[enginename]/[hostname]/context.xml.default with the contents:
context.xml.default:
<Context>
<Parameter name="myConfigDirectory" value="C:/myConfig" override="false"/>
</Context>
The parameter myConfigDirectory will be available to all the applications on the host. It is better to create this parameter in context.xml.default rather than in server.xml, because the file can be changed later without restarting tomcat.
In the applicationContext.xml inside war you can access config.properties using the SpEL expression: "#{contextParameters.myConfigDirectory + servletContext.contextPath}/config.properties", so for example you can write:
applicationContext.xml:
<bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="location" value="file:#{contextParameters.myConfigDirectory + servletContext.contextPath}/config.properties" />
</bean>
The expression will get expanded to C:/myConfig/app1 for application with contextPath /app1, and C:/myConfig/app2 for application with contextPath /app2. This will make the applications access the config.properties file based on their contextPath.
If you want to be fully portable between web containers you cannot rely on anything outside your WAR-file. In Tomcat the SecurityManager allows you to discover the physical location on disk where your code is deployed, and you can then use that knowledge to navigate the disk to a location where your configuration file is placed.
See e.g. Determine location of a java class loaded by Matlab