Django分页查询并返回jsons数据(中文乱码解决方法)

下面详细解释一下如何在Django中进行分页查询并返回JSON格式的数据，并解决中文乱码问题。

1. 安装相关依赖库

首先需要安装以下两个库:

• django-pure-pagination (https://pypi.org/project/django-pure-pagination/)
• django-core-extensions (https://pypi.org/project/django-core-extensions/)

可以使用pip进行安装：

pip install django-pure-pagination django-core-extensions

2. 修改settings配置

在settings.py中添加以下配置：

INSTALLED_APPS = [
    # ...
    'pure_pagination',
    'core_extensions',
]

# Pagination settings
PAGINATION_SETTINGS = {
    'PAGE_RANGE_DISPLAYED': 5,
    'MARGIN_PAGES_DISPLAYED': 2,
    'SHOW_FIRST_PAGE_WHEN_INVALID': True,
}

3. 创建分页处理类

在app目录下创建一个pagination.py文件，添加以下代码：

from pure_pagination import Paginator, PageNotAnInteger

class PaginationHandler():

    def __init__(self, request, queryset, page_size=10, prefetch_related=None, select_related=None):
        self.request = request
        self.queryset = queryset
        self.page_size = page_size
        self.prefetch_related = prefetch_related
        self.select_related = select_related

    def get_paginated_data(self):
        page = self.request.GET.get('page', 1)

        # 如果传进来的数据中有额外的关联表，使用select_related和prefetch_related优化查询速度
        queryset = self.queryset
        if self.prefetch_related:
            queryset = queryset.prefetch_related(*self.prefetch_related)
        if self.select_related:
            queryset = queryset.select_related(*self.select_related)

        paginator = Paginator(queryset, self.page_size, request=self.request)

        try:
            data = paginator.page(page)
        except PageNotAnInteger:
            data = paginator.page(1)
        except Exception:
            data = []

        return {
            'current_page': data.number,
            'total_pages': paginator.num_pages,
            'has_previous': data.has_previous(),
            'has_next': data.has_next(),
            'previous_page_number': data.previous_page_number(),
            'next_page_number': data.next_page_number(),
            'object_list': list(data),
        }

4. 编写视图函数

在views.py中定义视图函数，处理分页和JSON数据返回，例如：

from django.http import JsonResponse
from .models import Post
from .pagination import PaginationHandler

def post_list(request):
    data = Post.objects.all()

    # 获取分页处理类
    paginator = PaginationHandler(request, data)

    # 获取分页数据
    paginated_data = paginator.get_paginated_data()

    # 返回JSON格式数据
    return JsonResponse(paginated_data, safe=False)

5. 解决返回JSON数据中文乱码问题

在JSONResponse时需要加入参数json_dumps_params={'ensure_ascii':False}，将ensure_ascii设置为False，以解决中文乱码问题，例如：

return JsonResponse(paginated_data, json_dumps_params={'ensure_ascii':False}, safe=False)

至此，我们就完成了Django分页查询并返回JSON数据并解决中文乱码问题的完整攻略。

以下是示例代码：

分页处理类示例

from django.http import request
from django.test import TestCase

from .pagination import PaginationHandler
from .models import Post


class PaginationTestCase(TestCase):

    def setUp(self):
        for i in range(1, 16):
            Post.objects.create(title=f"Post {i}", body="body content...")

        self.request = request.HttpRequest()
        self.request.GET['page'] = 1

        self.handler = PaginationHandler(self.request, Post.objects.all())

    def test_paginator(self):
        paginated_data = self.handler.get_paginated_data()

        self.assertEqual(paginated_data['current_page'], 1)
        self.assertEqual(paginated_data['total_pages'], 2)
        self.assertEqual(paginated_data['has_previous'], False)
        self.assertEqual(paginated_data['has_next'], True)
        self.assertEqual(paginated_data['previous_page_number'], None)
        self.assertEqual(paginated_data['next_page_number'], 2)
        self.assertEqual(len(paginated_data['object_list']), 10)
        self.assertEqual(paginated_data['object_list'][0].title, 'Post 1')

    def test_select_related(self):
        paginated_data = PaginationHandler(self.request, Post.objects.all(), select_related=['user']).get_paginated_data()

        self.assertEqual(len(paginated_data['object_list']), 10)
        self.assertEqual(paginated_data['object_list'][0].user.username, 'admin')

    def test_prefetch_related(self):
        paginated_data = PaginationHandler(self.request, Post.objects.all(), prefetch_related=['comments']).get_paginated_data()

        self.assertEqual(len(paginated_data['object_list']), 10)
        self.assertEqual(len(paginated_data['object_list'][0].comments.all()), 2)

视图函数示例

from django.http import JsonResponse
from .models import Post
from .pagination import PaginationHandler

def post_list(request):
    data = Post.objects.all()

    # 获取分页处理类
    paginator = PaginationHandler(request, data)

    # 获取分页数据
    paginated_data = paginator.get_paginated_data()

    # 返回JSON格式数据
    return JsonResponse(paginated_data, json_dumps_params={'ensure_ascii':False}, safe=False)