标头参数如何用于RequestMapping注释？

Question

When I write inside controller method:

response.setHeader("Content-Disposition", "attachment; filename=mockDump.csv");

It works good.

But when I adds in @RequestMapping argument headers = {"Content-Disposition=attachment", "filename=mockDump.csv"}

method doesn't invoke.

Why?

Answer 1

The @RequestMapping header describes headers which must be present on the request for it to be routed to the annotated method for handling. Where as calling setHeader on a response object sets a header to be sent to the client in the repsonse

Answer 2

As the @RequestMapping#headers javadoc states

The headers of the mapped request, narrowing the primary mapping.

In other words, headers applies to the request headers, helping to determine the appropriate handler method.

If you want the Spring way of adding response headers, ie. not through the HttpServletResponse , return a ResponseEntity with an appropriate HttpHeaders set.