它可用作名称为referer的HTTP请求标头(是的，拼写错误应该是referrer).

It's available as HTTP request header with the name referer (yes, with the misspelling which should have been referrer).

String referrer = request.getHeader("referer");
// ...

此处request是 HttpServletRequest 在Spring bean中可用的几种方式，其中@AutoWired可用.

请记住，这是一个客户端控制的值，很容易被客户端欺骗/忽略.

Please keep in mind that this is a client-controlled value which can easily be spoofed/omitted by the client.