1xx: 100-101 information prompt
2xx: 200-206 success
3xx: 300-307 redirect
4xx: 400-415 error information, client error
5xx: 500-505 error information, server error
200: Success, the request data is sent through the entity-body part of the response message; OK
301: The resource pointed to by the requested URL has been deleted; but the header Location in the response message specifies the current location of the resource; Moved Permanently #Permanent redirection
302: The response message Location indicates the temporary new location of the resource Moved Temporarily #Temporary redirection
304: The client sends a conditional request, but the resource on the server has not changed, and the client is notified by responding to this response status code ；Not Modified #Cache
307: Browser internal redirection
401: Account and password authentication is required to access resources; Unauthorized
403: Request is forbidden; Forbidden
404: The server cannot find the resource requested by the client; Not Found
500: Inside the server Error; Internal Server Error
502: The proxy server received a fake response from the backend server, such as unable to connect to the gateway; Bad Gateway
503: Service unavailable, temporary server maintenance or overload, the server cannot process the request
504: Gateway timeout