java - Android中的HttpUrlConnection设置范围被忽略

Question

我正在尝试使用 Android 从我的服务器获取 206 响应。

这是代码。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_splash);
    new AsyncTask<Void, Void, Void>() {
        @Override
        protected Void doInBackground(Void... params) {
            try {
                URL url = new URL("http://aviddapp.com/10mb.file");
                HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
                urlConnection.setRequestProperty("Range", "bytes=1-2");
                urlConnection.connect();

                System.out.println("Response Code: " + urlConnection.getResponseCode());
                System.out.println("Content-Length: " + urlConnection.getContentLength());
                Map<String, List<String>> map = urlConnection.getHeaderFields();
                for (Map.Entry<String, List<String>> entry : map.entrySet()) {
                    System.out.println("Key : " + entry.getKey() +
                            " ,Value : " + entry.getValue());
                }
                InputStream inputStream = urlConnection.getInputStream();
                long size = 0;

                while(inputStream.read() != -1 )
                    size++;

                System.out.println("Downloaded Size: " + size);

            }catch(MalformedURLException mue) {
                mue.printStackTrace();
            }catch(IOException ioe) {
                ioe.printStackTrace();
            }
            return null;
        }
    }.execute();
}

这是输出:

I/System.out: Respnse Code: 200
I/System.out: Content-Length: -1
I/System.out: Key : null ,Value : [HTTP/1.1 200 OK]
I/System.out: Key : Accept-Ranges ,Value : [bytes]
I/System.out: Key : Cache-Control ,Value : [max-age=604800, public]
I/System.out: Key : Connection ,Value : [Keep-Alive]
I/System.out: Key : Date ,Value : [Tue, 04 Oct 2016 07:45:22 GMT]
I/System.out: Key : ETag ,Value : ["a00000-53e051f279680-gzip"]
I/System.out: Key : Expires ,Value : [Tue, 11 Oct 2016 07:45:22 GMT]
I/System.out: Key : Keep-Alive ,Value : [timeout=5, max=100]
I/System.out: Key : Last-Modified ,Value : [Tue, 04 Oct 2016 07:36:42 GMT]
I/System.out: Key : Server ,Value : [Apache/2.4.12 (Unix) OpenSSL/1.0.1e-fips mod_bwlimited/1.4]
I/System.out: Key : Transfer-Encoding ,Value : [chunked]
I/System.out: Key : Vary ,Value : [Accept-Encoding,User-Agent]
I/System.out: Key : X-Android-Received-Millis ,Value : [1475567127403]
I/System.out: Key : X-Android-Response-Source ,Value : [NETWORK 200]
I/System.out: Key : X-Android-Sent-Millis ,Value : [1475567127183]
I/System.out: Downloaded Size: 10485760

现在我在做同样的事情是纯java。

public static void main(String... args) {
    try {
        URL url = new URL("http://aviddapp.com/10mb.file");
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
        urlConnection.setRequestProperty("Range", "bytes=1-2");
        urlConnection.connect();

        System.out.println("Respnse Code: " + urlConnection.getResponseCode());
        System.out.println("Content-Length: " + urlConnection.getContentLength());
        Map<String, List<String>> map = urlConnection.getHeaderFields();
        for (Map.Entry<String, List<String>> entry : map.entrySet()) {
            System.out.println("Key : " + entry.getKey() +
                    " ,Value : " + entry.getValue());
        }
        InputStream inputStream = urlConnection.getInputStream();
        long size = 0;

        while(inputStream.read() != -1 )
            size++;

        System.out.println("Downloaded Size: " + size);

    }catch(MalformedURLException mue) {
        mue.printStackTrace();
    }catch(IOException ioe) {
        ioe.printStackTrace();
    }
}

这是输出

Respnse Code: 206
Content-Length: 2
Key : Keep-Alive ,Value : [timeout=5, max=100]
Key : null ,Value : [HTTP/1.1 206 Partial Content]
Key : Server ,Value : [Apache/2.4.12 (Unix) OpenSSL/1.0.1e-fips mod_bwlimited/1.4]
Key : Content-Range ,Value : [bytes 1-2/10485760]
Key : Connection ,Value : [Keep-Alive]
Key : Last-Modified ,Value : [Tue, 04 Oct 2016 07:36:42 GMT]
Key : Date ,Value : [Tue, 04 Oct 2016 07:42:17 GMT]
Key : Accept-Ranges ,Value : [bytes]
Key : Cache-Control ,Value : [max-age=604800, public]
Key : ETag ,Value : ["a00000-53e051f279680"]
Key : Vary ,Value : [Accept-Encoding,User-Agent]
Key : Expires ,Value : [Tue, 11 Oct 2016 07:42:17 GMT]
Key : Content-Length ,Value : [2]
Downloaded Size: 2

如您所见，我在这两种情况下都得到了不同的响应代码。似乎 Android 没有将 Range 传递给服务器？这里发生了什么？

PS:如果文件大小为 1mb，我会得到 206。

Answer 1

我比较确定错误不在Android代码中。

看起来服务器可能会提供虚假结果。

您可以通过 third party tool (such as Postman) 查询确定 Web 服务正在传递的 header 。

我使用 Postman 的结果。如您所见，它传递的是 HTTP 200(不是 206)。它也没有限制 Content-Length。如果服务器是你的，也许检查它是否配置正确。同时检查您的代码与其他服务器。