Django:You called this URL via POST, but the URL doesn't end in a slash and you have APP END_SLASH s

RuntimeError: You called this URL via POST, but the URL doesn't end in a slash and you have APP
END_SLASH set. Django can't redirect to the slash URL while maintaining POST data. Change your
form to point to 127.0.0.1:9000/set_teacher.html/?cid=3/ (note the trailing slash), or set APPE
ND_SLASH=False in your Django settings.
 

发生这个错误的几种原因:

1. 发送的url结尾看是否有 /

2 .如果带有参数的话？前面一定也要有/，下面是错误的写法:

正确的写法:

主要是python 3.7中url是这么写的：