Use of a env. variable as a path to a prop. file: how to simplify the definition?

[Injecteer]

hi all,
in the system, that I am supporting, the majority of config params are stored in a config.properties file (which is a pretty common way). The path to that file is stored as an environment variable, like

export SYSTEM_CONFIG=/home/me/config.properties

now, when I tried to use the property values from the file in placeholders, it works. The only thing I need to perfrom is to add a prefix "file:" to denote an absolute path in the file system.

Beans' definition looks like

  <bean id="propFilePath" class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="targetObject">
      <bean class="java.lang.String"><constructor-arg value="file:"/></bean>
    </property>
    <property name="targetMethod" value="concat"/>
    <property name="arguments">
      <list>
        <bean class="java.lang.System" factory-method="getenv">
          <constructor-arg value="SYSTEM_CONFIG"/>
        </bean>
      </list>
    </property>
  </bean>

  <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
      <list>
        <ref bean="propFilePath"/>
      </list>
    </property>
  </bean>

where the "propFilePath" bean is doing nothing more, than concatenates "file:" and the result of System.getenv( "SYSTEM_CONFIG" ).

But this def look too complex...

are there any ways to simplify it? apart from parent contexts ?

[Mark Fisher]

You can do the following:

  <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location">
      <bean class="org.springframework.core.io.FileSystemResource">
        <constructor-arg>
          <bean class="java.lang.System" factory-method="getenv">
            <constructor-arg value="SYSTEM_CONFIG"/>
          </bean>
        </constructor-arg>
      </bean>
    </property>
  </bean>

[Mark Fisher]

Actually, sorry this is much better...

  <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="file:/${SYSTEM_CONFIG}"/>
  </bean>

...since propertyPlaceholderConfigurer can access system env vars - and can also apply to its own placeholder.

[Injecteer]

thnax Mark, it works, of course

[memelet]

I'm not seeing this behavior. When PropertyPlaceholderConfigurer.loadProperties() runs it does make any attempt to resolve variables in the location names.

  <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="location" value="file:/${SYSTEM_CONFIG}"/>
  </bean>

...since propertyPlaceholderConfigurer can access system env vars - and can also apply to its own placeholder.

[Injecteer]

that nice way works only in Spring 2++.

[thiamteck]

Hi, I am using Spring 2.5.6 and it found that it work for me at windows but not on Linux.

Below is my config:

<beans:bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <beans:property name="locations">
        	<beans:list>
        		<beans:value>file:/${CONFIG_HOME}</beans:value>
        		<beans:value>classpath:core.properties</beans:value>
        		<beans:value>classpath:plugin.properties</beans:value>
        	</beans:list>
        </beans:property>
        <beans:property name="ignoreUnresolvablePlaceholders" value="true"/>
        <beans:property name="searchSystemEnvironment" value="true"/>
        <beans:property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE"/>
    </beans:bean>

below is the exception:

org.springframework.beans.factory.BeanInitializationException: Could not load properties; nested exception is java.io.FileNotFoundException: /${CONFIG_HOME} (No such file or directory)
        at org.springframework.beans.factory.config.PropertyResourceConfigurer.postProcessBeanFactory(PropertyResourceConfigurer.java:78)
        at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:553)
        at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:527)
        at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:362)
        at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
        at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:93)
        at com.unified.cgw.CGW.main(CGW.java:23)
Caused by: java.io.FileNotFoundException: /${CONFIG_HOME} (No such file or directory)
        at java.io.FileInputStream.open(Native Method)
        at java.io.FileInputStream.<init>(FileInputStream.java:106)
        at java.io.FileInputStream.<init>(FileInputStream.java:66)
        at sun.net.www.protocol.file.FileURLConnection.connect(FileURLConnection.java:70)
        at sun.net.www.protocol.file.FileURLConnection.getInputStream(FileURLConnection.java:161)
        at org.springframework.core.io.UrlResource.getInputStream(UrlResource.java:123)
        at org.springframework.core.io.support.PropertiesLoaderSupport.loadProperties(PropertiesLoaderSupport.java:182)
        at org.springframework.core.io.support.PropertiesLoaderSupport.mergeProperties(PropertiesLoaderSupport.java:161)
        at org.springframework.beans.factory.config.PropertyResourceConfigurer.postProcessBeanFactory(PropertyResourceConfigurer.java:69)
        ... 6 more

Any idea what went wrong with my configuration?

[denis.zhdanov]

Error message is clear enough - '/${CONFIG_HOME} (No such file or directory)'

[thiamteck]

I solve the problem by changing the configuration to

<beans:bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <beans:property name="searchSystemEnvironment" value="true"/>
        <beans:property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE"/>
        <beans:property name="locations">
        	<beans:list>
        		<beans:value>file:/${CONFIG_HOME}</beans:value>
        		<beans:value>classpath:core.properties</beans:value>
        		<beans:value>classpath:plugin.properties</beans:value>
        	</beans:list>
        </beans:property>
        <beans:property name="ignoreUnresolvablePlaceholders" value="true"/>
        
    </beans:bean>