對于web應(yīng)用開發(fā)而言，有一項(xiàng)功能是相當(dāng)常見的，那就是分頁，而這項(xiàng)功能最關(guān)鍵的作用，就是實(shí)現(xiàn)將數(shù)據(jù)分成一頁一頁的效果，這樣每次就能閱讀有限數(shù)量的數(shù)據(jù)，既降低了服務(wù)器壓力又提高了閱讀效率，而分頁功能的實(shí)現(xiàn)必須實(shí)現(xiàn)兩個小功能，分別是數(shù)據(jù)分頁和翻頁功能，接下來小編就以Django為例介紹一下Django如何實(shí)線分頁，以及Django如何實(shí)現(xiàn)翻頁功能吧。
一、views模塊導(dǎo)入Paginator類實(shí)現(xiàn)數(shù)據(jù)分頁
ApiTest/apiviews.py
每行都加了注釋，希望有助于理解。
from django.shortcuts import render
from ApiTest.models import ApiTest
from django.contrib.auth.decorators import login_required
from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger, InvalidPage
@login_required
def api_test_manage(request):
username = request.session.get('user', '')
# 獲取所有接口測試數(shù)據(jù)
apitest_list = ApiTest.objects.all().order_by('id')
# 生成Paginator對象對數(shù)據(jù)分頁，每頁顯示10條數(shù)據(jù)
paginator = Paginator(apitest_list,10)
# 使用request.GET.get()函數(shù)獲取url中的page參數(shù)的數(shù)值。默認(rèn)第1頁
page = request.GET.get('page', 1)
# 把獲取的當(dāng)前頁碼數(shù)轉(zhuǎn)換成整數(shù)類型
current_page = int(page)
try:
# 獲取查詢頁數(shù)的接口數(shù)據(jù)列表，page()函數(shù)會判斷page實(shí)參是否是有效數(shù)字。page()函數(shù)源碼附在文章的最后
apitest_list = paginator.page(page)
except PageNotAnInteger:
apitest_list = paginator.page(1)
except (EmptyPage, InvalidPage):
# paginator.num_pages
apitest_list = paginator.page(paginator.num_pages)
return render(request, "apitest_manage.html", {'user': username, 'apitests': apitest_list})二、將views的數(shù)據(jù)渲染到前端模板上
在對應(yīng)的html文件中加入此段代碼即可。
<div class="container">
<ul class="pagination" id="pager">
{# 上一頁鏈接 #}
{% if apitests.has_previous %}
<li class="previous"><a href="/apitest_manage/?page={{ apitests.previous_page_number }}" rel="external nofollow" >上一頁</a></li>
{% else %}
<li class="previous disabled"><a href="#" rel="external nofollow" rel="external nofollow" >上一頁</a></li>
{% endif %}
{# 中間數(shù)字顯示 #}
{% for num in apitests.paginator.page_range %}
{% if num == currentPage %}
<li class="item active"><a href="/apitest_manage/?page={{ num }}" rel="external nofollow" rel="external nofollow" >{{ num }}</a></li>
{% else %}
<li class="item"><a href="/apitest_manage/?page={{ num }}" rel="external nofollow" rel="external nofollow" >{{ num }}</a></li>
{% endif %}
{% endfor %}
{# 下一頁鏈接 #}
{% if apitests.has_next %} {# 如果有下一頁，則正常顯示下一頁鏈接 #}
<li class="next"><a href="/apitest_manage/?page={{ apitests.next_page_number }}" rel="external nofollow" >下一頁</a></li>
{% else %}
<li class="next disabled"><a href="#" rel="external nofollow" rel="external nofollow" >下一頁</a></li>
{% endif %}
</ul>
</div>三、效果展示
四、Paginator類源碼
此類主要用在views文件
class Paginator:
def __init__(self, object_list, per_page, orphans=0,
allow_empty_first_page=True):
self.object_list = object_list
self._check_object_list_is_ordered()
self.per_page = int(per_page)
self.orphans = int(orphans)
self.allow_empty_first_page = allow_empty_first_page
def validate_number(self, number):
"""Validate the given 1-based page number."""
try:
if isinstance(number, float) and not number.is_integer():
raise ValueError
number = int(number)
except (TypeError, ValueError):
raise PageNotAnInteger(_('That page number is not an integer'))
if number < 1:
raise EmptyPage(_('That page number is less than 1'))
if number > self.num_pages:
if number == 1 and self.allow_empty_first_page:
pass
else:
raise EmptyPage(_('That page contains no results'))
return number
def get_page(self, number):
"""
Return a valid page, even if the page argument isn't a number or isn't
in range.
"""
try:
number = self.validate_number(number)
except PageNotAnInteger:
number = 1
except EmptyPage:
number = self.num_pages
return self.page(number)
def page(self, number):
"""Return a Page object for the given 1-based page number."""
number = self.validate_number(number)
bottom = (number - 1) * self.per_page
top = bottom + self.per_page
if top + self.orphans >= self.count:
top = self.count
return self._get_page(self.object_list[bottom:top], number, self)
def _get_page(self, *args, **kwargs):
"""
Return an instance of a single page.
This hook can be used by subclasses to use an alternative to the
standard :cls:`Page` object.
"""
return Page(*args, **kwargs)
@cached_property
def count(self):
"""Return the total number of objects, across all pages."""
c = getattr(self.object_list, 'count', None)
if callable(c) and not inspect.isbuiltin(c) and method_has_no_args(c):
return c()
return len(self.object_list)
@cached_property
def num_pages(self):
"""Return the total number of pages."""
if self.count == 0 and not self.allow_empty_first_page:
return 0
hits = max(1, self.count - self.orphans)
return ceil(hits / self.per_page)
@property
def page_range(self):
"""
Return a 1-based range of pages for iterating through within
a template for loop.
"""
return range(1, self.num_pages + 1)
def _check_object_list_is_ordered(self):
"""
Warn if self.object_list is unordered (typically a QuerySet).
"""
ordered = getattr(self.object_list, 'ordered', None)
if ordered is not None and not ordered:
obj_list_repr = (
'{} {}'.format(self.object_list.model, self.object_list.__class__.__name__)
if hasattr(self.object_list, 'model')
else '{!r}'.format(self.object_list)
)
warnings.warn(
'Pagination may yield inconsistent results with an unordered '
'object_list: {}.'.format(obj_list_repr),
UnorderedObjectListWarning,
stacklevel=3
)五、Page類源碼
此類主要用在html文件
class Page(collections.abc.Sequence):
def __init__(self, object_list, number, paginator):
self.object_list = object_list
self.number = number
self.paginator = paginator
def __repr__(self):
return '<Page %s of %s>' % (self.number, self.paginator.num_pages)
def __len__(self):
return len(self.object_list)
def __getitem__(self, index):
if not isinstance(index, (int, slice)):
raise TypeError(
'Page indices must be integers or slices, not %s.'
% type(index).__name__
)
# The object_list is converted to a list so that if it was a QuerySet
# it won't be a database hit per __getitem__.
if not isinstance(self.object_list, list):
self.object_list = list(self.object_list)
return self.object_list[index]
def has_next(self):
return self.number < self.paginator.num_pages
def has_previous(self):
return self.number > 1
def has_other_pages(self):
return self.has_previous() or self.has_next()
def next_page_number(self):
return self.paginator.validate_number(self.number + 1)
def previous_page_number(self):
return self.paginator.validate_number(self.number - 1)
def start_index(self):
"""
Return the 1-based index of the first object on this page,
relative to total objects in the paginator.
"""
# Special case, return zero if no items.
if self.paginator.count == 0:
return 0
return (self.paginator.per_page * (self.number - 1)) + 1
def end_index(self):
"""
Return the 1-based index of the last object on this page,
relative to total objects found (hits).
"""
# Special case for the last page because there can be orphans.
if self.number == self.paginator.num_pages:
return self.paginator.count
return self.number * self.paginator.per_page小結(jié)
到此這篇關(guān)于Django如何實(shí)現(xiàn)翻頁的文章就介紹到這了,更多Django相關(guān)內(nèi)容請搜索W3Cschool以前的文章或繼續(xù)瀏覽下面的相關(guān)文章。希望大家以后多多支持W3Cschool！
