Django Paginator
Django 分页官方文档 https://docs.djangoproject.com/en/1.10/topics/pagination/
此分页方法没有限制显示出来的页码的个数，会显示全部的页码，待改进。
后端代码
由于代码是先object_list = model_obj.model.objects.all()，然后调用 paginator = Paginator(object_list, 2)，如果数据量很大就会消耗很多的性能。
如果是这样呢写呢？ paginator = Paginator(model_obj.model.objects.all(), 2） 这样能利用queryset的惰性机制吗？
看了下Paginator源码，应该是可行的
class Paginator(object):
def __init__(self, object_list, per_page, orphans=0,
allow_empty_first_page=True):
self.object_list = object_list
self.per_page = int(per_page)
self.orphans = int(orphans)
self.allow_empty_first_page = allow_empty_first_page
def validate_number(self, number):
"""
Validates the given 1-based page number.
"""
try:
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 page(self, number):
"""
Returns 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):
"""
Returns 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):
"""
Returns the total number of objects, across all pages.
"""
try:
return self.object_list.count()
except (AttributeError, TypeError):
# AttributeError if object_list has no count() method.
# TypeError if object_list.count() requires arguments
# (i.e. is of type list).
return len(self.object_list)
@cached_property
def num_pages(self):
"""
Returns 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 int(ceil(hits / float(self.per_page)))
@property
def page_range(self):
"""
Returns a 1-based range of pages for iterating through within
a template for loop.
"""
return six.moves.range(1, self.num_pages + 1)
QuerySetPaginator = Paginator # For backwards-compatibility.
Paginator 部分源码
#需要导入 的模块
from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger def display_table_objs(request,app_name,table_name):
print(app_name,'----',table_name)
#获取数据库数据
model_obj = king_admin.enabled_admins[app_name][table_name] #分页
object_list = model_obj.model.objects.all()
paginator = Paginator(object_list, 2) # Show 2 contacts per page
# paginator = JuncheePaginator(object_list, 1) # Show 2 contacts per page page = request.GET.get('page')
try:
contacts = paginator.page(page)
except PageNotAnInteger:
# If page is not an integer, deliver first page.
contacts = paginator.page(1)
except EmptyPage:
# If page is out of range (e.g. 9999), deliver last page of results.
contacts = paginator.page(paginator.num_pages) return render(request,'king_admin/table_objs.html',{"model_obj":model_obj,
"query_sets":contacts,})
前端模板代码
其中的标签样式引用的Bootstrap的样式
<ul class="pagination">
{# topics.paginator.page_range 这个函数返回包含一个所有页码数的 range 对象 #}
{# 即 range(1, topics.paginator.num_pages + 1) #}
{% if query_sets.has_previous %}
<li><a href="?page={{ query_sets.previous_page_number }}">上一页</a></li>
{% else %}
<li><span>没了</span></li>
{% endif %}
{% for page_number in query_sets.paginator.page_range %} {% ifequal page_number query_sets.number %}
<li class="disabled"><span>{{ page_number }}</span></li> {% else %}
<li ><a href="?page={{ page_number }}">{{ page_number }}</a></li> {% endifequal %}
{% endfor %} {% if query_sets.has_next %}
<li><a href="?page={{ query_sets.next_page_number }}">下一页</a></li>
{% else %}
<li><span>没了</span></li>
{% endif %}
</ul>
效果如下：
