分页

解决大数据分页的效率问题：

• 记录当前访问页的数据ID，在发送下一页的访问请求时，SQL语句中进行约束（id>page_size*page_num）
• 最多显示120页（参考抽屉新热榜）
• 只显示上一页下一页按钮，对页码加密

django-restframework中有三种分页类：

• LimitOffsetPagination——基于offest+limit

• PageNumberPagination——基于页码

• CursorPagination——基于cursor

  ​

class LimitOffsetPagination(BasePagination):
    default_limit = api_settings.PAGE_SIZE  # 默认每页显示多少条
    limit_query_param = 'limit'  # 获取请求中每页显示条数时的key
    offset_query_param = 'offset'  # 偏移量的key
    max_limit = None  # 客户端每页最大请求条数

class PageNumberPagination(BasePagination):
    page_size = api_settings.PAGE_SIZE  # 默认每页显示多少条，默认为None，表示禁用分页
    page_query_param = 'page'  # 获取页数时的key
    page_size_query_param = None  # 客户端请求时，每页条数的key，可以设置为'page_size'
    max_page_size = None  # 客户端每页最大请求条数
    last_page_strings = ('last',)
    
    
class CursorPagination(BasePagination):
    cursor_query_param = 'cursor'
    page_size = api_settings.PAGE_SIZE  # 每页几条
    ordering = '-created'  # 排序
    page_size_query_param = None  # 客户端请求时，每页条数的key，可以设置为'page_size'
    max_page_size = None  # 最大请求到多少页
    offset_cutoff = 1000

使用

1.根据页码进行分页

urls.py

from django.conf.urls import url, include
from rest_framework import routers
from web.views import s9_pagination

urlpatterns = [
    url(r'^test/', s9_pagination.UserViewSet.as_view()),
]

views.py

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from rest_framework.views import APIView
from rest_framework import serializers
from .. import models

from rest_framework.pagination import PageNumberPagination


class StandardResultsSetPagination(PageNumberPagination):
    # 默认每页显示的数据条数
    page_size = 1
    # 获取URL参数中设置的每页显示数据条数
    page_size_query_param = 'page_size'

    # 获取URL参数中传入的页码key
    page_query_param = 'page'

    # 最大支持的每页显示的数据条数
    max_page_size = 1


class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.UserInfo
        fields = "__all__"


class UserViewSet(APIView):
    def get(self, request, *args, **kwargs):
        user_list = models.UserInfo.objects.all().order_by('-id')

        # 实例化分页对象，获取数据库中的分页数据
        paginator = StandardResultsSetPagination()
        page_user_list = paginator.paginate_queryset(user_list, self.request, view=self)

        # 序列化对象
        serializer = UserSerializer(page_user_list, many=True)

        # 生成分页和数据
        response = paginator.get_paginated_response(serializer.data)
        return response

2.根据位置和个数进行分页

urls.py

from django.conf.urls import url, include
from web.views import s9_pagination

urlpatterns = [
    url(r'^test/', s9_pagination.UserViewSet.as_view()),
]

views.py

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from rest_framework.views import APIView
from rest_framework import serializers
from .. import models

from rest_framework.pagination import PageNumberPagination,LimitOffsetPagination


class StandardResultsSetPagination(LimitOffsetPagination):
    # 默认每页显示的数据条数
    default_limit = 10
    # URL中传入的显示数据条数的参数
    limit_query_param = 'limit'
    # URL中传入的数据位置的参数
    offset_query_param = 'offset'
    # 最大每页显得条数
    max_limit = None

class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.UserInfo
        fields = "__all__"


class UserViewSet(APIView):
    def get(self, request, *args, **kwargs):
        user_list = models.UserInfo.objects.all().order_by('-id')

        # 实例化分页对象，获取数据库中的分页数据
        paginator = StandardResultsSetPagination()
        page_user_list = paginator.paginate_queryset(user_list, self.request, view=self)

        # 序列化对象
        serializer = UserSerializer(page_user_list, many=True)

        # 生成分页和数据
        response = paginator.get_paginated_response(serializer.data)
        return response

3.游标分页

urls.py

from django.conf.urls import url, include
from web.views import s9_pagination

urlpatterns = [
    url(r'^test/', s9_pagination.UserViewSet.as_view()),
]

views.py

#!/usr/bin/env python
# -*- coding:utf-8 -*-
from rest_framework.views import APIView
from rest_framework import serializers
from .. import models

from rest_framework.pagination import PageNumberPagination, LimitOffsetPagination, CursorPagination


class StandardResultsSetPagination(CursorPagination):
    # URL传入的游标参数
    cursor_query_param = 'cursor'
    # 默认每页显示的数据条数
    page_size = 2
    # URL传入的每页显示条数的参数
    page_size_query_param = 'page_size'
    # 每页显示数据最大条数
    max_page_size = 1000

    # 根据ID从大到小排列
    ordering = "id"



class UserSerializer(serializers.ModelSerializer):
    class Meta:
        model = models.UserInfo
        fields = "__all__"


class UserViewSet(APIView):
    def get(self, request, *args, **kwargs):
        user_list = models.UserInfo.objects.all().order_by('-id')

        # 实例化分页对象，获取数据库中的分页数据
        paginator = StandardResultsSetPagination()
        page_user_list = paginator.paginate_queryset(user_list, self.request, view=self)

        # 序列化对象
        serializer = UserSerializer(page_user_list, many=True)

        # 生成分页和数据
        response = paginator.get_paginated_response(serializer.data)
        return response