2020-06-01 http通信の為のサイト https://gihyo.jp/dev/serial/01/androidapp/0009 https://developer.android.com/training/basics/network-ops/connecting?hl=ja https://araramistudio.jimdo.com/2018/03/15/android%E3%81%A7http%E3%82%92%E4%BD%BF%E3%81%A3%E3%81%9F%E3%83%8D%E3%83%83%E3%83%88%E3%83%AF%E3%83%BC%E3%82%AF%E6%8E%A5%E7%B6%9A/ https://qiita.com/S-nobol/items/7929e2793c039770d73a https://akira-watson.com/android/httpurlconnection-post.html