- 2xx 一切正常。
- 3xx 被请求的资源已被移走。
- 4xx 因为客户端的错误导致请求无法处理（如请求一个不存在的资源）。
- 5xx 服务器在处理的过程中发生了错误（如意外情况发生）。 | status code | Definitions | | :---------: | :-----------------------------: | | 100 | Continue | | 101 | Switching Protocols | | 200 | OK | | 201 | Created | | 202 | Accepted | | 203 | Non-Authoritative Information | | 204 | No Content | | 205 | Reset Content | | 206 | Partial Content | | 300 | Multiple Choices | | 301 | Moved Permanently | | 302 | Found | | 303 | See Other | | 304 | Not Modified | | 305 | Use Proxy | | 307 | Temporary Redirect | | 400 | Bad Request | | 401 | Unauthorized | | 403 | Forbidden | | 404 | Not Found | | 405 | Method Not Allowed | | 406 | Not Acceptable | | 407 | Proxy Authentication Required | | 408 | Request Timeout | | 409 | Conflict | | 410 | Gone | | 411 | Length Required | | 412 | Precondition Failed | | 413 | Request Entity Too Large | | 414 | Request-URL Too Long | | 415 | Unsupported Media Type | | 416 | Requested Range Not Satisfiable | | 417 | Expectation Failed | | 500 | Internal Server Error | | 501 | Not Implemented | | 502 | Bad Gateway | | 503 | Service Unavailable | | 504 | Gateway Timeout | | 505 | HTTP Version Not Supported |