HTTP Response中的Status-Code

1XX : 通知信息。请求被接收，继续处理
2XX : 成功。请求动作被成功接收、理解和接受
3XX : 重定向。需要其他的动作来完成这个请求
4XX : 客户端错误。请求包含错误的语法或者缺少语法
5XX : 服务端错误。服务端无法完成有效的请求

上述状态码在HTTP/1.1中定义，下面是一组相关的错误原因。

1XX

100 ; Section 10.1.1: Continue
101 ; Section 10.1.2: Switching Protocols

2XX

200 ; Section 10.2.1: OK
201 ; Section 10.2.2: Created
202 ; Section 10.2.3: Accepted
203 ; Section 10.2.4: Non-Authoritative Information
204 ; Section 10.2.5: No Content
205 ; Section 10.2.6: Reset Content
206 ; Section 10.2.7: Partial Content

3XX

300 ; Section 10.3.1: Multiple Choices
301 ; Section 10.3.2: Moved Permanently
302 ; Section 10.3.3: Found
303 ; Section 10.3.4: See Other
304 ; Section 10.3.5: Not Modified
305 ; Section 10.3.6: Use Proxy
307 ; Section 10.3.8: Temporary Redirect

4XX

400 ; Section 10.4.1: Bad Request
401 ; Section 10.4.2: Unauthorized
402 ; Section 10.4.3: Payment Required
403 ; Section 10.4.4: Forbidden
404 ; Section 10.4.5: Not Found
405 ; Section 10.4.6: Method Not Allowed
406 ; Section 10.4.7: Not Acceptable
407 ; Section 10.4.8: Proxy Authentication Required
408 ; Section 10.4.9: Request Time-out
409 ; Section 10.4.10: Conflict
410 ; Section 10.4.11: Gone
411 ; Section 10.4.12: Length Required
412 ; Section 10.4.13: Precondition Failed
413 ; Section 10.4.14: Request Entity Too Large
414 ; Section 10.4.15: Request-URI Too Large
415 ; Section 10.4.16: Unsupported Media Type
416 ; Section 10.4.17: Requested range not satisfiable
417 ; Section 10.4.18: Expectation Failed

5XX

500 ; Section 10.5.1: Internal Server Error
501 ; Section 10.5.2: Not Implemented
502 ; Section 10.5.3: Bad Gateway
503 ; Section 10.5.4: Service Unavailable
504 ; Section 10.5.5: Gateway Time-out
505 ; Section 10.5.6: HTTP Version not supported

From: http://www.lvzejun.cn/2015/04/13/libvirt1md/