首先確認你的伺服器是支持 HTTP2，HTTP2配置方法可以參考 《Netkiller Web 手札》

下面是我的例子僅供參考，Nginx 開啟 http2 代理後面的 Spring Cloud 介面。

		
server {
    listen       80;
    listen 443 ssl http2;
    server_name  api.netkiller.cn;

    ssl_certificate ssl/netkiller.cn.crt;
    ssl_certificate_key ssl/netkiller.cn.key;
    ssl_session_cache shared:SSL:20m;
    ssl_session_timeout 60m;

    charset utf-8;
    access_log  /var/log/nginx/api.netkiller.cn.access.log;

    error_page  497              https://$host$uri?$args;

    if ($scheme = http) {
        return 301 https://$server_name$request_uri;
    }

    location / {
		proxy_pass   http://127.0.0.1:8000;
        proxy_http_version 1.1;
		proxy_set_header    Host    $host;
		proxy_set_header    X-Forwarded-For $proxy_add_x_forwarded_for;	
    }

    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #    deny  all;
    #}
}		
		
		

安卓程序如下

		
		String url = "https://api.netkiller.cn/member/json";

        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder().url(url).build();
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                Log.d("okhttp", "Connect timeout. " + e.getMessage());
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                String text = response.body().string();
                Log.d("okhttp", "HTTP Code " + response.code() + " TEXT " + text);
                Log.d("okhttp", "Protocol: " + response.protocol());
            }
        });
		
		

運行結果

		
D/okhttp: HTTP Code 200 TEXT {"status":false,"reason":"","code":0,"data":{"id":null,"username":"12322228888","mobile":"12322228888","password":"123456","wechat":"微信ID","role":"Organization","captcha":null,"createDate":"2018-10-25 09:25:23","updateDate":null}}
    Protocol: h2
		
		

輸出 h2 表示當前介面與伺服器連接是通過 http2 完成。