T - the data type@FunctionalInterface public interface ResponseExtractor<T>
RestTemplate's retrieval methods
 Implementations of this interface perform the actual work of extracting data
 from a ClientHttpResponse, but don't need to worry about exception
 handling or closing resources.
 Used internally by the RestTemplate, but also useful for
 application code. There is one available factory method, see
 RestTemplate.responseEntityExtractor(Type).
| Modifier and Type | Method and Description | 
|---|---|
| T | extractData(ClientHttpResponse response)Extract data from the given  ClientHttpResponseand return it. | 
@Nullable T extractData(ClientHttpResponse response) throws IOException
ClientHttpResponse and return it.response - the HTTP responseIOException - in case of I/O errors