利用URLConnection来发送POST和GET请求

https://blog.csdn.net/ws_kfxd/article/details/85070404?utm_medium=distribute.pc_relevant.none-task-blog-title-7&spm=1001.2101.3001.4242

（入参为json）https://blog.csdn.net/LONG_Yi_1994/article/details/107531419?utm_medium=distribute.pc_relevant_t0.none-task-blog-BlogCommendFromBaidu-1.control&depth_1-utm_source=distribute.pc_relevant_t0.none-task-blog-BlogCommendFromBaidu-1.control