200 ok
201 created
202 accepted
204 not content
206 partical content

301 moved permanently
302 found
303 see other 也是重定向
304 not modified
307 temporary redirect 临时重定向

400 bad request
401 unauthorized
403 forbidden
404 not found
408 request timeout
409 conflict

500 internal server error
501 not implemented
503 service unavailable
505 http version not supported