python测试开发django-rest-framework-86.分页查询功能(PageNumberPagination)

前言

当查询出来的数据量非常大的时候，需要分页查询，django-rest-framework 提供了分页的支持。
有三种分页功能：PageNumberPagination，LimitOffsetPagination，CursorPagination。

分页器

django-rest-framework 分页器有三种：

• PageNumberPagination 简单分页（查看第n页，每页显示N条）
• LimitOffsetPagination 偏移分页（在第n个位置，向后查看n条数据）
• CursorPagination 加密分页，只能看上一页和下一页，速度快

简单分页(PageNumberPagination)

我们可以在配置文件中设置全局的分页方式, 这里设置简单分页(PageNumberPagination)，每页显示10条数据

REST_FRAMEWORK = {
    'DEFAULT_PAGINATION_CLASS':  'rest_framework.pagination.PageNumberPagination',
    'PAGE_SIZE': 5  # 每页数目
}

也可以自己重写PageNumberPagination类，定义分页方式

from rest_framework.pagination import PageNumberPagination
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# blog地址 https://www.cnblogs.com/yoyoketang/


class MyPageNumberPagination(PageNumberPagination):
    page_size = 5                    # 默认每页显示的多少条记录
    page_query_param = 'page'        # 默认查询参数名为 page
    page_size_query_param = 'size'   # 前台控制每页显示的最大条数
    max_page_size = 20              # 后台控制显示的最大记录条数

PageNumberPagination类可以设置以下属性

• page_size 数字，页面显示的记录条数，不设置的就默认setting配置的全局PAGE_SIZE值
• page_query_param 字符串，查询参数的名称，不设置默认是'page'
• page_size_query_param 字符串，请求设置页面大小的参数名称，默认是None
• max_page_size 最大允许请求的页面大小，仅在page_size_query_param被设置时有效
• last_page_string 字符串列表或元组，默认是 ('last',)
• template 分页空间使用的模板名称，可以覆盖或设置为None，默认'rest_framework/pagination/numbers.html'

APIView使用分页查询

写查询视图的时候，先序列化，再定义分页器,查询的时候可以带上参数/api/v1/goods?page=1&size=10

from rest_framework import serializers
from .models import Goods
from rest_framework.pagination import PageNumberPagination
from rest_framework.permissions import IsAuthenticated, AllowAny
# 作者-上海悠悠 QQ交流群:717225969
# blog地址 https://www.cnblogs.com/yoyoketang/


# 序列化 Goods 模型
class GoodsAPISerializer(serializers.ModelSerializer):

    class Meta:
        model = Goods
        fields = '__all__'  # 返回全部的字段

# 定义分页器简单分页(PageNumberPagination)
class MyPageNumberPagination(PageNumberPagination):
    page_size = 5                    # 默认每页显示的多少条记录
    page_query_param = 'page'        # 默认查询参数名为 page
    page_size_query_param = 'size'   # 前台控制每页显示的最大条数
    max_page_size = 20               # 后台控制显示的最大记录条数


# 查询视图
class GoodsAPISView(APIView):
    permission_classes = (AllowAny,)      # AllowAny 允许所有用户


    def get(self, request, *args, **kwargs):
        '''返回所有的'''
        page = MyPageNumberPagination()
        goods = Goods.objects.all()   # 查询全部
        ret = page.paginate_queryset(goods, request)
        serializer = GoodsAPISerializer2(ret, many=True)

        return Response({
            "code": 0,
            "msg": "success!",
            "data": serializer.data
        })

分页查询

如果不带参数，直接请求，会返回默认的 5 条数据http://localhost:8000/api/v1/goods

{
	"code": 0,
	"msg": "success!",
	"data": [{
		"id": 1,
		"create_time": "2021-01-17 15:14:25",
		"update_time": "2021-01-19 10:02:05",
		"goodsname": "《selenium入门到精通3》",
		"goodscode": "sp_100049",
		"merchantid": "10001",
		"merchantname": "悠悠学堂",
		"goodsprice": 52.365,
		"stock": 100,
		"goodsgroupid": 0,
		"goodsstatus": 1
	}, {
		"id": 13,
		"create_time": "2021-01-16 20:12:36",
		"update_time": "2021-01-17 09:41:05",
		"goodsname": "《selenium入门到精通》",
		"goodscode": "sp_100008",
		"merchantid": "10001",
		"merchantname": "悠悠学堂",
		"goodsprice": 49.9,
		"stock": 100,
		"goodsgroupid": 0,
		"goodsstatus": 1
	}, {
		"id": 14,
		"create_time": "2021-01-16 20:12:42",
		"update_time": "2021-01-17 09:41:05",
		"goodsname": "《selenium入门到精通》",
		"goodscode": "sp_100009",
		"merchantid": "10001",
		"merchantname": "悠悠学堂",
		"goodsprice": 49.9,
		"stock": 100,
		"goodsgroupid": 0,
		"goodsstatus": 1
	}, {
		"id": 101,
		"create_time": "2021-01-16 21:24:10",
		"update_time": "2021-01-17 09:41:05",
		"goodsname": "",
		"goodscode": "sp_10086",
		"merchantid": "",
		"merchantname": "",
		"goodsprice": 0.0,
		"stock": 0,
		"goodsgroupid": 0,
		"goodsstatus": 1
	}, {
		"id": 102,
		"create_time": "2021-01-16 21:26:23",
		"update_time": "2021-01-17 09:41:05",
		"goodsname": "",
		"goodscode": "sp_10087",
		"merchantid": "",
		"merchantname": "",
		"goodsprice": 0.0,
		"stock": 0,
		"goodsgroupid": 0,
		"goodsstatus": 1
	}]
}

带上 page 和 size 参数查询,指定查询的 page 页数和 size 数量http://localhost:8000/api/v1/goods?page=1&size=2

{
	"code": 0,
	"msg": "success!",
	"data": [{
		"id": 1,
		"create_time": "2021-01-17 15:14:25",
		"update_time": "2021-01-19 10:02:05",
		"goodsname": "《selenium入门到精通3》",
		"goodscode": "sp_100049",
		"merchantid": "10001",
		"merchantname": "悠悠学堂",
		"goodsprice": 52.365,
		"stock": 100,
		"goodsgroupid": 0,
		"goodsstatus": 1
	}, {
		"id": 13,
		"create_time": "2021-01-16 20:12:36",
		"update_time": "2021-01-17 09:41:05",
		"goodsname": "《selenium入门到精通》",
		"goodscode": "sp_100008",
		"merchantid": "10001",
		"merchantname": "悠悠学堂",
		"goodsprice": 49.9,
		"stock": 100,
		"goodsgroupid": 0,
		"goodsstatus": 1
	}]
}