Java中的HTTP / 2响应头(HTTP/2 Response Header in Java)

Java中的HTTP / 2响应头(HTTP/2 Response Header in Java)

有没有办法在Java中获取HTTP / 2响应头？ 我试图搜索URLConnection，Undertow甚至Jetty等一些库，但没有成功。

PS：我在Java Project上使用JDK 1.7。

另外，HTTP / 2的响应头是这样的吗？

GET / HTTP/1.1 Host: server.example.com Connection: Upgrade, HTTP2-Settings Upgrade: h2c HTTP2-Settings: <base64url encoding of HTTP/2 SETTINGS payload>

有没有网站使用过这个版本？

我的主要目标是知道一个网站是否使用HTTP / 2版本，是否有办法知道这一点而无需在Java项目中读取响应头？

谢谢。

Is there already a way to get the HTTP/2 response header in Java? I've tried to search in some libraries like URLConnection, Undertow or even Jetty, but without success.

P.S.: I'm using JDK 1.7 on my Java Project.

Other thing, the response header of the HTTP/2 is like this?

GET / HTTP/1.1 Host: server.example.com Connection: Upgrade, HTTP2-Settings Upgrade: h2c HTTP2-Settings: <base64url encoding of HTTP/2 SETTINGS payload>

Is there any website who use this version already?

My main goal is to know if a website use the HTTP/2 version or not, is there a way to know this without need to read the response header in a Java Project?

Thanks.

最满意答案

HTTP / 2网站通常使用TLS，因为浏览器仅通过TLS支持HTTP / 2。

您尝试使用的方法是HTTP / 1.1升级到HTTP / 2，很少有站点（如果有的话）支持。

您的代码片段代表请求 ，而不是响应。 如果升级成功，HTTP / 2服务器将以HTTP / 1.1格式发回101响应， 并以HTTP / 2格式发送对GET请求的响应。 这在RFC 7540第3.2节中规定。

为了实现您想要的，即知道网站是否支持HTTP / 2，您必须尝试使用​​HTTP / 2 + TLS进行连接。 如果连接成功，则表示支持HTTP / 2。 如果失败，则不受支持。

对于Jetty（免责声明，我是HTTP / 2模块维护者），您必须使用JDK 8，代码如下所示：

// Setup.
HTTP2Client http2Client = new HTTP2Client();
SslContextFactory sslContextFactory = new SslContextFactory();
HttpClient httpClient = new HttpClient(new HttpClientTransportOverHTTP2(http2Client), sslContextFactory);
httpClient.start();

// Does webtide.com support HTTP/2 ?
ContentResponse response = httpClient.GET("https://webtide.com/");
// No errors, yes it supports HTTP/2 !
 
 如果您收到没有错误的响应，则表示您使用HTTP / 2，否则服务器不支持HTTP / 2。 
 
 请记住，要使该代码起作用，您必须在bootclasspath中使用JDK 8和正确的ALPN引导jar，如此处所指定。 
HTTP/2 websites typically use TLS, because browsers only support HTTP/2 over TLS.
 
The method you are trying to use is the HTTP/1.1 upgrade to HTTP/2 which very few sites - if any at all - support.
 
Your snippet of code represent a request, not a response. If the upgrade is successful, the HTTP/2 server sends back a 101 response in HTTP/1.1 format and the response to the GET request in HTTP/2 format. This is specified in RFC 7540, section 3.2.
 
In order to achieve what you want, i.e. to know if a website supports HTTP/2, you have to try to connect using HTTP/2 + TLS. If the connection succeeds, you know HTTP/2 is supported. If it fails, it's not supported.
 
For Jetty (disclaimer, I'm the HTTP/2 module maintainer), you have to use JDK 8, and the code will look like this:
 
// Setup.
HTTP2Client http2Client = new HTTP2Client();
SslContextFactory sslContextFactory = new SslContextFactory();
HttpClient httpClient = new HttpClient(new HttpClientTransportOverHTTP2(http2Client), sslContextFactory);
httpClient.start();

// Does webtide.com support HTTP/2 ?
ContentResponse response = httpClient.GET("https://webtide.com/");
// No errors, yes it supports HTTP/2 !
 
If you get a response without errors, you are on HTTP/2, otherwise the server does not support HTTP/2.
 
Remember that for that code to work, you have to use JDK 8 and the proper ALPN boot jar in the bootclasspath, as specified here.