drf框架里面的针对bigint字段的序列化字段，主要原因是前端js对于bigint类型字段会有精度缺失

serializer_bigintfield.py

import copy
from rest_framework import serializers
from django.db import models
from rest_framework.fields import IntegerField

class BigIntegerField(IntegerField):
    def to_representation(self, value):
        return str(value)


class BigIntegerPKRelField(serializers.PrimaryKeyRelatedField):
    def __init__(self, **kwargs):
        kwargs['pk_field'] = BigIntegerField()
        super().__init__(**kwargs)


class MyModelSerializer(serializers.ModelSerializer):
    serializer_field_mapping = copy.deepcopy(serializers.ModelSerializer.serializer_field_mapping)
    serializer_field_mapping[models.BigIntegerField] = BigIntegerField
    serializer_related_field = BigIntegerPKRelField