状态码
为了方便设置状态码，REST framewrok在rest_framework.status模块中提供了常用状态码常量。
导入: from rest_framework import status
提示: 默认响应状态码200
1）信息告知 - 1xx
HTTP_100_CONTINUE
HTTP_101_SWITCHING_PROTOCOLS
2）成功 - 2xx
HTTP_200_OK
HTTP_201_CREATED
HTTP_202_ACCEPTED
HTTP_203_NON_AUTHORITATIVE_INFORMATION
HTTP_204_NO_CONTENT
HTTP_205_RESET_CONTENT
HTTP_206_PARTIAL_CONTENT
HTTP_207_MULTI_STATUS
3）重定向 - 3xx
HTTP_300_MULTIPLE_CHOICES
HTTP_301_MOVED_PERMANENTLY
HTTP_302_FOUND
HTTP_303_SEE_OTHER
HTTP_304_NOT_MODIFIED
HTTP_305_USE_PROXY
HTTP_306_RESERVED
HTTP_307_TEMPORARY_REDIRECT
4）客户端错误 - 4xx
HTTP_400_BAD_REQUEST
HTTP_401_UNAUTHORIZED
HTTP_402_PAYMENT_REQUIRED
HTTP_403_FORBIDDEN
HTTP_404_NOT_FOUND
HTTP_405_METHOD_NOT_ALLOWED
HTTP_406_NOT_ACCEPTABLE
HTTP_407_PROXY_AUTHENTICATION_REQUIRED
HTTP_408_REQUEST_TIMEOUT
HTTP_409_CONFLICT
HTTP_410_GONE
HTTP_411_LENGTH_REQUIRED
HTTP_412_PRECONDITION_FAILED
HTTP_413_REQUEST_ENTITY_TOO_LARGE
HTTP_414_REQUEST_URI_TOO_LONG
HTTP_415_UNSUPPORTED_MEDIA_TYPE
HTTP_416_REQUESTED_RANGE_NOT_SATISFIABLE
HTTP_417_EXPECTATION_FAILED
HTTP_422_UNPROCESSABLE_ENTITY
HTTP_423_LOCKED
HTTP_424_FAILED_DEPENDENCY
HTTP_428_PRECONDITION_REQUIRED
HTTP_429_TOO_MANY_REQUESTS
HTTP_431_REQUEST_HEADER_FIELDS_TOO_LARGE
HTTP_451_UNAVAILABLE_FOR_LEGAL_REASONS
5）服务器错误 - 5xx
HTTP_500_INTERNAL_SERVER_ERROR
HTTP_501_NOT_IMPLEMENTED
HTTP_502_BAD_GATEWAY
HTTP_503_SERVICE_UNAVAILABLE
HTTP_504_GATEWAY_TIMEOUT
HTTP_505_HTTP_VERSION_NOT_SUPPORTED
HTTP_507_INSUFFICIENT_STORAGE
HTTP_511_NETWORK_AUTHENTICATION_REQUIRED