7.1/8.1/9
adb shell "settings put global captive_portal_http_url http://captive.v2ex.co/generate_204"
adb shell "settings put global captive_portal_https_url https://captive.v2ex.co/generate_204"
adb shell settings put global captive_portal_https_url https://www.google.cn/generate_204
5.1
adb shell "settings put global captive_portal_server www.google.cn"