问如何通过OSGi blueprint属性占位符和Java DSL加载外部属性文件

EN

<blueprint xmlns="http://www.osgi.org/xmlns/blueprint/v1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:camel-cxf="http://camel.apache.org/schema/blueprint/cxf"
xmlns:jaxrs="http://cxf.apache.org/jaxrs" xmlns:cxf="http://cxf.apache.org/blueprint/core"
xsi:schemaLocation="
    http://cxf.apache.org/jaxrs http://cxf.apache.org/schemas/jaxrs.xsd
    http://camel.apache.org/schema/cxf http://camel.apache.org/schema/cxf/camel-cxf.xsd
    http://cxf.apache.org/blueprint/core http://cxf.apache.org/schemas/blueprint/core.xsd
    http://camel.apache.org/schema/blueprint/cxf http://camel.apache.org/schema/blueprint/cxf/camel-cxf.xsd"
xmlns:cm="http://aries.apache.org/blueprint/xmlns/blueprint-cm/v1.0.0">

<cm:property-placeholder id="myProperties" persistent-id="abc" />

public class MyActivator implements BundleActivator {

    @Override
    public void start(final BundleContext context) throws Exception {
        final ServiceReference serviceReference = context.getServiceReference(ConfigurationAdmin.class.getName());
        if (serviceReference != null) {

            final ConfigurationAdmin admin = (ConfigurationAdmin) context.getService(serviceReference);
            final Configuration configuration = admin.getConfiguration("abc");
            final Dictionary<String, Object> configurations = configuration.getProperties();

            if (configurations == null) {
                throw new CustomException("Exception in loading properties file");
            }
            populateProperties(configurations);
        }
    }
}