在使用RestTemplate請求服務(wù)端，獲取授權(quán)碼時， 會經(jīng)過兩次的 HTTP 302 Found 跳轉(zhuǎn)，開發(fā)者在實(shí)現(xiàn)時需要允許客戶端跟隨跳轉(zhuǎn)。
解決辦法來自Stack Overflow的一個問答：Spring RestTemplate redirect 302

相關(guān)代碼：

final RestTemplate restTemplate = new RestTemplate();
final HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory();
final HttpClient httpClient = HttpClientBuilder.create()
                                               .setRedirectStrategy(new LaxRedirectStrategy())
                                               .build();
factory.setHttpClient(httpClient);
restTemplate.setRequestFactory(factory);

其中用到的HttpComponentsClientHttpRequestFactory、HttpClientBuilder、HttpClient等類，可以用maven來引入：

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
        </dependency>