为什么HTTP的请求头多了个冒号

那是因为这部分带冒号的请求头是HTTP2协议中新增的部分
HTTP2中所有协议是小写字母，这点跟HTTP1不同。
另外部分新增的协议用冒号开头，称之为 pseudo header name

The pseudo header names where chosen to begin with a colon because
that would be an illegal character for a header name in HTTP/1.1.
HTTP/1.1 does not use pseudo header names.

[https://stackoverflow.com/que...]{.ul}