Referencing a value from a spring config

Question

First a bit of setup info:

I have a multi-tenant spring based application. The multi-tenant enabling library is an in-house developed tool where I work that I have to use. How it works is that there is an interceptor that sets in front of the servlet for the application. Upon a request hitting the servlet it loads a tenant specific spring config for "stuff" needed for the tenant specified on the url hitting the servlet.

As stated, the above is just a bit of background. Now to the issue/question:

What I want to do is to create, in the tenant configuration that is loaded, a value that I can use to inject where I need. So, is there a way I can just define a constant in a spring config and then reference it via @Value or @Resource in java code?

There will be no bean implementation behind it, it would just be purely and only a key/value that I can reference where needed in my application by name. So, something to the effect of:

<bean name="MyIdentifier">
    <property name="theId" value="1001" />
</bean>

And then can I do something like?

@Value{MyIdentifier.theId}
String theId;

And have Spring be aware of and inject the value. The problem is that doing something like above Spring complains there is no implementation for the bean. Notice, no class specified for the bean. The reason I want to do this is every tenant config file will contain this bean, but the actual value will vary per tenant.

Is there some other type to use in the config to do this? If so, what schemas have to be on the config?

I am guessing I am either trying to make Spring do something not intended, or, this is so simple I cannot see it since I have stared at it too long. Anyway, thanks for the help.

Answer 1

You can not create bean tag in configuration file without providing class implementation. If you want to inject the value of fields, you have to go for properties file instead.

Create property file as below:

application.properties

theId=1001

Load property file in your configuration:

 <bean class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer">
        <property name="ignoreUnresolvablePlaceholders" value="true"/>
        <property name="locations">
          <list>
            <value>classpath:application.properties</value>
          </list>
        </property>
      </bean>

And access the property in your concrete class:

  @Value("${theId}")
    String theId;