MappingJackson2HttpMessageConverter 默认只支持 application/json 格式，，如果服务器返回的是text/plain不能转换

扩展一个可以转换text/plain的转换器：

public class RestTemplateMessageConverter extends MappingJackson2HttpMessageConverter {public RestTemplateMessageConverter() {List<MediaType> mediaTypeList = new ArrayList<>();mediaTypeList.add(MediaType.APPLICATION_JSON);mediaTypeList.add(MediaType.TEXT_PLAIN);setSupportedMediaTypes(mediaTypeList);}
}

注入restTemplate

  @Beanpublic RestTemplate restTemplate(){RestTemplate restTemplate = new RestTemplate();List<HttpMessageConverter<?>> messageConverters = restTemplate.getMessageConverters();messageConverters.add(new RestTemplateMessageConverter());return restTemplate;}