Okhttp not selecting http2 on Android 7.0

问题:

I am trying to make an HTTP request to the following domain (http2 enabled) on a device running on Android 7.0.

The code i use is as follows:

Request request = new Request.Builder()
                .url("https://http2.akamai.com/")
                .build();

response = okHttpClient.newCall(request).execute();
statusCode = response.code();

As I notice in the response object, the protocol used by okHttp is HTTP 1.1

The behavior of the okhttp client is random, at one time I was able to see the protocol as h2 but then repeating the request, it kept selecting HTTP 1.1

I am using okhttp v3.5

What am i possibly missing out here ?

回答1:

Android has enabled only HTTP/1.1 in its OkHttp.

/**
 * Creates an OkHttpClient suitable for creating HttpsURLConnection instances on
 * Android.
 */
public static OkUrlFactory createHttpsOkUrlFactory(Proxy proxy) {
  ...
  // Only enable HTTP/1.1 (implies HTTP/1.0). Disable SPDY / HTTP/2.0.
  okHttpClient.setProtocols(HTTP_1_1_ONLY);

https://android.googlesource.com/platform/external/okhttp/+/master/android/main/java/com/squareup/okhttp/HttpsHandler.java#75