3

我的代码如下

WebResource webResource1 = cl.resource("https://api.box.com/2.0/files/{fileId}/content");

ClientResponse res1 = webResource1.header("Authorization", "Bearer"+p1.getAccess_token()).get(ClientResponse.class);
String jsonStr1 = res1.getEntity(String.class);

我的回应如下 -

{Object-Id=[file_20317568941], Cache-control=[private], Date=[Wed, 24 Sep 2014 12:11:43 GMT], Content-Length=[27], X-Robots-Tag=[noindex, nofollow], Content-Disposition=[attachment;filename="upload.txt";filename*=UTF-8''upload.txt], Accept-Ranges=[bytes, bytes], Connection=[keep-alive], Content-Type=[text/plain; charset=UTF-8], Server=[nginx], X-Content-Type-Options=[nosniff]}

我收到状态码200, OK；但要获得location属性，我需要状态码302以及位置 url ( https://dl.boxcloud.com/*)。

如果没有在响应中获取location: https://dl.boxcloud.com/*属性，我如何从 box api 下载文件？

4

1 回答 1

2

上周六我有时间调查你的问题。基本问题是，如果您需要获取Location值，您需要停止自动重定向。以下是您的问题的解释和解决方案：

引用下载文件的 Box API 文档：

如果该文件可供下载，则响应将是 302 Found 到 dl.boxcloud.com 的 URL。

来自关于HTTP 302的维基百科文章：

HTTP 响应状态码 302 Found 是执行 URL 重定向的常用方法。

带有此状态代码的 HTTP 响应将在 Location 标头字段中另外提供一个 URL。带有此代码的响应邀请用户代理（例如 Web 浏览器）向 Location 字段中指定的新 URL 发出第二个（否则相同）请求。

因此，要获取Location响应标头中的属性，您需要停止自动重定向。否则，根据 box doc，您将获得文件的原始数据，而不是下载 URL。

以下是使用Commons HTTPClient实现的解决方案：

private static void getFileDownloadUrl(String fileId, String accessToken) {
    try {
        String url = MessageFormat.format("https://api.box.com/2.0/files/{0}/content", fileId);
        GetMethod getMethod = new GetMethod(url);
        getMethod.setFollowRedirects(false);

        Header header = new Header(); 
        header.setName("Authorization");
        header.setValue("Bearer " + accessToken);
        getMethod.addRequestHeader(header);

        HttpClient client = new HttpClient();
        client.executeMethod(getMethod);

        System.out.println("Status Code: " + getMethod.getStatusCode());
        System.out.println("Location: " + getMethod.getResponseHeader("Location"));
    } catch (Exception cause) {
        cause.printStackTrace();
    }
}

使用的替代解决方案java.net.HttpURLConnection：

private static void getFileDownloadUrl(String fileId, String accessToken) {
    try {
        String serviceURL = MessageFormat.format("https://api.box.com/2.0/files/{0}/content", fileId);
        URL url = new URL(serviceURL);

        HttpURLConnection connection = HttpURLConnection.class.cast(url.openConnection());
        connection.setRequestProperty("Authorization", "Bearer " + accessToken);
        connection.setRequestMethod("GET");
        connection.setInstanceFollowRedirects(false);
        connection.connect();

        int statusCode = connection.getResponseCode();
        System.out.println("Status Code: " + statusCode);

        Map<String, List<String>> headerFields = connection.getHeaderFields();
        List<String> locations = headerFields.get("Location");

        if(locations != null && locations.size() > 0) {
            System.out.println("Location: " + locations.get(0));
        }
    } catch (Exception cause) {
        cause.printStackTrace();
    }
}

由于 Commons HTTPClient 已过时，以下解决方案基于Apache HttpComponents：

private static void getFileDownloadUrl(String fileId, String accessToken) {
    try {
        String url = MessageFormat.format("https://api.box.com/2.0/files/{0}/content", fileId);
        CloseableHttpClient client = HttpClientBuilder.create().disableRedirectHandling().build();
        HttpGet httpGet = new HttpGet(url);
        BasicHeader header = new BasicHeader("Authorization", "Bearer " + accessToken);
        httpGet.setHeader(header);
        CloseableHttpResponse response = client.execute(httpGet);
        int statusCode = response.getStatusLine().getStatusCode();
        System.out.println("Status Code: " + statusCode);

        org.apache.http.Header[] headers = response.getHeaders(HttpHeaders.LOCATION);

        if(header != null && headers.length > 0) {
            System.out.println("Location: " + headers[0]);
        }
    } catch (Exception cause) {
        cause.printStackTrace();
    }
}
于 2014-10-20T08:28:52.633 回答