https://pay.weixin.qq.com/wiki/doc/apiv3/wxpay/tool/chapter3_1.shtml
post.addHeader("User-Agent", "androidClient")
post.addHeader("Content-Type", "multipart/form-data;charset=utf-8");
<html>
<head><title>501 Not Implemented</title></head>
<body bgcolor="white">
<center><h1>501 Not Implemented</h1></center>
<hr><center>nginx</center>
</body>
</html>
您好，请参考：https://developers.weixin.qq.com/community/pay/article/doc/00082aa48cc8d04629f9ee1ee51813