spring property substitution for test and production

Question

I ran into this for property substitution in spring

<context:property-placeholder location="esb-project-config.properties"/>

but unfortunately, we don't want this in the xml file as we want to re-use the file in our tests but swap in the test.properties file for test. ie. we want to test all the production bindings but with properties that are suitable for test like localhost for instance. How can we load the ApplicationContext but with different properties files?

thanks, Dean

Answer 1

several approaches:

---

1. 'Order' Property

in src/main/resources/your-conf.xml

<context:property-placeholder 
         location="classpath:esb-project-config.properties"
         order="1"/>

in src/test/resources/your-test-config.xml

<context:property-placeholder 
         location="classpath:esb-project-config.properties"
         order="0"/>

If you running your test with src/test/resources as a test classpath, the above will ensure to override src/main/resources/esb-project-config.properties with the src/test/resources/esb-project-config.properties.

This will override the whole property-placeholder though, so you would have to provide all the properties needed in your application in for this test property-placeholder. e.g.

<context:property-placeholder 
         location="classpath:esb-project-config.properties,
                   classpath:some-other-props-if-needed.properties"
         order="0"/>

---

2. PropertyOverrideConfigurer

 <context:property-override 
          location="classpath:esb-project-config.test.properties"/>

to override certain individual properties. Some examples here

---

3. System Variables

You can use a prefix to control environment specific properties, this can be done by using system variables:

 <context:property-placeholder 
          location="${ENV_SYSTEM:dev}/esb-project-config.properties"/>

In this case it will always look under:

 <context:property-placeholder 
          location="dev/esb-project-config.properties"/>

by default, unless a ENV_SYSTEM system variable is set. If it is set to qa, for example, it will automatically look under:

 <context:property-placeholder 
          location="qa/esb-project-config.properties"/>

---

4. Spring Profiles

Another approach is to make beans profile specific. For example:

<beans profile="dev">
  <context:property-placeholder 
           location="esb-project-config.dev.properties"/>
</beans>

<beans profile="qa">
  <context:property-placeholder 
           location="esb-project-config.qa.properties"/>
</beans>

The appropriate esb-project-config will loaded depending on a profile set. For example this will load esb-project-config.dev.properties:

GenericXmlApplicationContext ctx = new GenericXmlApplicationContext();
ctx.getEnvironment().setActiveProfiles( "dev" );
ctx.load( "classpath:/org/boom/bang/config/xml/*-config.xml" );
ctx.refresh();

---

• NOTE: "System Variables" and "System Profiles" approaches are usually used to switch between different environments rather than just "dev <==> test" in dev mode, but still are useful capabilities to be aware of.