Django 我可以构建一个序列化程序来验证用户名和电子邮件是否存在于is_valid调用中吗？

伙计们！ 我有这个用于用户模型的序列化器类

class UserSerializer(serializers.ModelSerializer):
    username = serializers.RegexField("^(?=.{6,20}$)(?![_.])(?!.*[_.]{2})[a-zA-Z0-9._]+(?<![_.])$")
    full_name = serializers.RegexField("^([a-zA-Z]{2,}\s[a-zA-Z]{1,}'?-?[a-zA-Z]{2,}\s?([a-zA-Z]{1,})?)")
    email = serializers.EmailField()
    phone = serializers.RegexField("^(\+\d{1,2}\s?)?1?\-?\.?\s?\(?\d{3}\)?[\s.-]?\d{3}[\s.-]?\d{4}$")

    class Meta:
        model = User
        fields = ['username', 'full_name', 'email', 'password', 'phone']

class UserSerializer（serializers.ModelSerializer）：
username=serializers.RegexField（“^（？=.{6,20}$）（？！[.]]）（？！.[.]{2}）[a-zA-Z0-9.+（？您可以使用
验证{fieldname}
验证字段：

class UserSerializer(serializers.ModelSerializer):
    username = serializers.RegexField("^(?=.{6,20}$)(?![_.])(?!.*[_.]{2})[a-zA-Z0-9._]+(?<![_.])$")
    full_name = serializers.RegexField("^([a-zA-Z]{2,}\s[a-zA-Z]{1,}'?-?[a-zA-Z]{2,}\s?([a-zA-Z]{1,})?)")
    email = serializers.EmailField()
    phone = serializers.RegexField("^(\+\d{1,2}\s?)?1?\-?\.?\s?\(?\d{3}\)?[\s.-]?\d{3}[\s.-]?\d{4}$")

    class Meta:
        model = User
        fields = ['username', 'full_name', 'email', 'password', 'phone']


    def validate_username(self, value):
        if User.objects.filter(username=value).exists():
            raise serializers.ValidationError("A user with this username already exists!")
        return value

    def validate_email(self, value):
        if User.objects.filter(email=value).exists():
            raise serializers.ValidationError("A user with this email already exists!")
        return value


class UserSerializer（serializers.ModelSerializer）：
username=serializers.RegexField（“^（？=.{6,20}$）（？！[\.]）（？！.[\.]{2}）[a-zA-Z0-9.\]+（？您需要编写字段级验证程序方法