apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/environment/DefaultPortalMetaServerProvider.java/DefaultPortalMetaServerProvider/getDomainsFromSystemProperty
class DefaultPortalMetaServerProvider:    private Map<Env, String> getDomainsFromSystemProperty() {
        // find key-value from System Property which key ends with "_meta" (case insensitive)
        Map<String, String> metaServerAddressesFromSystemProperty = KeyValueUtils.filterWithKeyIgnoreCaseEndsWith(System.getProperties(), "_meta");
        // remove key's suffix "_meta" (case insensitive)
        metaServerAddressesFromSystemProperty = KeyValueUtils.removeKeySuffix(metaServerAddressesFromSystemProperty, "_meta".length());
        return transformToEnvMap(metaServerAddressesFromSystemProperty);
    }