让RestTemplate使用和解析gzip编码

Spring Boot 的RestTemplate默认不使用 Gzip，也不解析 Gzip编码结果。所以当处理 Gzip的结果会时报错类似以下信息：

 Illegal character ((CTRL-CHAR, code 31)): only regular white space (\r, \n, \t) is allowed .. 

解决办法：

用来自Apache HttpClient的默认requestFactory替换默认的requestFactory（它将动态解码GZIP）：

// 添加拦截器，使用 gzip 编码提交
ClientHttpRequestInterceptor interceptor = (httpRequest, bytes, execution) -> {
    httpRequest.getHeaders().set("user-agent",   "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36");
    httpRequest.getHeaders().set(HttpHeaders.ACCEPT,  MediaType.APPLICATION_JSON_VALUE);
    httpRequest.getHeaders().set(HttpHeaders.ACCEPT_ENCODING, "gzip");   // 使用 gzip 编码提交
    return execution.execute(httpRequest, bytes);
};  

HttpComponentsClientHttpRequestFactory clientHttpRequestFactory = new HttpComponentsClientHttpRequestFactory(HttpClientBuilder.create().build());
RestTemplate restTemplate = new RestTemplate(clientHttpRequestFactory);
restTemplate.getInterceptors().add(interceptor);

将Apache Http Client添加到pom.xml

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <!--Version is not needed when used with Spring Boot parent pom file -->
    <version>4.5.1</version>
</dependency>