code: public static Object getValue(String registryName, String key) {
  		Map<String, Object> registry = getRegistry(registryName);
  		if (registry == null || StringUtils.isBlank(key)) {
  			return null;
  		}
  		return registry.get(key);
  	}
docs: Retrieve one specific value from a registry.
  @param registryName the name of the registry.
  @param key the unique key corresponding to the value to retrieve (typically an appid).
  @return the value corresponding to the registry key, null if no value is found for the specified key.