Django無法得到POST請求的參數(shù)？

在使用axios向后端發(fā)送POST請求的時候，服務(wù)器無法得到POST中帶有的參數(shù)。
前端的發(fā)送代碼如下：

Http({
    method:'POST',
    url:'signup',
    data:{
        username:this.signUpform.username,
        password:this.signUpform.password,
        email:this.signUpform.email,
        cellphone:this.signUpform.cellphone
    }
})

Axios設(shè)置如下：

import axios from 'axios'
export default axios.create({
  baseURL: 'http://127.0.0.1:8000/api',
  timeout: 20000,
  headers: {'Content-Type': 'application/json'}
})

后臺接受代碼如下：

@require_http_methods(["POST"])
def signup(request):
    response = {}
    try:
        print(request.POST.get('username'))
        WorkUser.objects.get(username=request.POST.get('username'))
        response['error'] = 'username already exist'
    except WorkUser.DoesNotExist:
        wu=tools.toWorkUser(request)
        wu.save()
        response['error'] = 'success'
        
    return JsonResponse(response)

輸出，顯示：

None
Internal Server Error: /api/signup
Traceback (most recent call last):
  File "C:\Users\fengfanfan\AppData\Local\Programs\Python\Python36\lib\site-packages\django\utils\datastructures.py", line 77, in __getitem__
    list_ = super().__getitem__(key)
KeyError: 'username'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\fengfanfan\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\handlers\exception.py", line 35, in inner
    response = get_response(request)
  File "C:\Users\fengfanfan\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\handlers\base.py", line 128, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "C:\Users\fengfanfan\AppData\Local\Programs\Python\Python36\lib\site-packages\django\core\handlers\base.py", line 126, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Users\fengfanfan\AppData\Local\Programs\Python\Python36\lib\site-packages\django\views\decorators\http.py", line 40, in inner
    return func(request, *args, **kwargs)
  File "E:\WorkSpace\GraduationThesis\GPServer\server\views.py", line 36, in signup
    WorkUser.objects.get(username=request.POST['username'])
  File "C:\Users\fengfanfan\AppData\Local\Programs\Python\Python36\lib\site-packages\django\utils\datastructures.py", line 79, in __getitem__
    raise MultiValueDictKeyError(key)
django.utils.datastructures.MultiValueDictKeyError: 'username'

然而，使用Postman接口卻可以使用，這是為什么呢