RestClientException

throw ResourceAccessException

catch (IOException )

HttpMessageNotReadableException

response extractData

finallyresponse.close()

ResourceAccessException

读取response流，字符转换

HttpMessageConversionException

NestedRuntimeException

throw IOExceptionHttpMessageNotReadableExceptionRestClientException（没有匹配的HttpMessageConverter）

根据response状态码，处理异常

捕获IOException，转成ResourceAccessException抛出

HttpMessageNotWritableException

HttpStatusCodeException

throw IOExceptionHttpMessageNotWritableExceptionRestClientException（没有匹配的HttpMessageConverter）

RuntimeException

HttpServerErrorException

handleResponse

HttpClientErrorException

execute

doWithRequest

doExecute

try

UnknownHttpStatusCodeException

IOException

createRequest

throw IOExceptionNoHttpResponseException

装载http header，http body 根据配置的HttpMessageConverter做字符对象转换

NoHttpResponseException

RestClientException

1 createHttpUriRequest（根据http method创建request）2 createHttpContext（创建HttpClientContext，填充属性http.request-config）

RestClientResponseException

40x，throw HttpClientErrorException50x，throw HttpServerErrorException其他情况，throw RestClientException(Unknown status code);

throw IOException

request.execute() 拿到response