This is a kind of follow up from my previous post. In which I describe an example implementation of a Hibernate MultiTenantConnectionProvider and CurrentTenantIdentifierResolver. Later after writing I thought it would better to abstract the database configuration in these two files into a .properties file - so that the properties can be reused in other areas of the application such as when authenicating a user.

Normally when you wish to use a .properties file in a spring application, you define a property placeholder in your context xml (or Java config) like so:

<context:property-placeholder location="classpath:filename.properties" />

Then if you want to access the properties in a spring bean , you can use the @Value annotation in the bean class to inject the required property.

@Value("${property.value}")
private String property;

Now this is an easy way to access your properties, however there is a situation which I've discovered that requires a different approach. If the class you wish to pass the properties to does not get initialised as a spring bean - such as the MultiTenantConnectionProvider in my previous post, then you cannot use the @Value annotation. In this case it is because only the class name is given to hibernate which it will then make an instance of internally.

A workaround for this is to access the properties file using a ClassLoader inside the MultiTenantConnectionProvider constructor.

private Properties properties;

public MultiTenantConnectionProvider(){
    properties = new Properties();
    ClassLoader loader = Thread.currentThread().getContextClassLoader();
    InputStream stream = loader.getResourceAsStream("filename.properties");
    properties.load(stream);

    defaultDataSource = new ComboPooledDataSource(properties.getProperty("shared_database.name"));

   // rest of constructor omitted
}

This way you still access your properties anywhere inside a non-bean class.