在web开发中，分页是必不可少的功能，Flask实现展示内容的分页也非常简单，这里通过实例来学习一下Flask如何为网站分页。
首先，自定义一个分页工具类page_utils：
from urllib import urlencode
class Pagination(object):
def __init__(self, current_page, total_count, base_url, params, per_page_count=10, max_pager_count=11):
try:
current_page = int(current_page)
except Exception as e:
current_page = 1
if current_page <=0:
current_page = 1
self.current_page = current_page
self.total_count = total_count
self.per_page_count = per_page_count
max_page_num, div = divmod(total_count, per_page_count)
if div:
max_page_num += 1
self.max_page_num = max_page_num
self.max_pager_count = max_pager_count
self.half_max_pager_count = int((max_pager_count - 1) / 2)
self.base_url = base_url
import copy
params = copy.deepcopy(params)
get_dict = params.to_dict()
self.params = get_dict
@property
def start(self):
return (self.current_page - 1) * self.per_page_count
@property
def end(self):
return self.current_page * self.per_page_count
def page_html(self):
if self.max_page_num <= self.max_pager_count:
pager_start = 1
pager_end = self.max_page_num
# 如果总页数 > 11
else:
if self.current_page <= self.half_max_pager_count:
pager_start = 1
pager_end = self.max_pager_count
else:
if (self.current_page + self.half_max_pager_count) > self.max_page_num:
pager_end = self.max_page_num
pager_start = self.max_page_num - self.max_pager_count + 1 #倒这数11个
else:
pager_start = self.current_page - self.half_max_pager_count
pager_end = self.current_page + self.half_max_pager_count
page_html_list = []
self.params['page'] = 1
first_page = '<li><a href="%s?%s">首页</a></li>'.decode("utf-8") % (self.base_url,urlencode(self.params),)
page_html_list.append(first_page)
self.params["page"] = self.current_page - 1
if self.params["page"] < 1:
pervious_page = '<li class="disabled"><a href="%s?%s" aria-label="Previous">上一页</span></a></li>'.
decode("utf-8") % (self.base_url, urlencode(self.params))
else:
pervious_page = '<li><a href = "%s?%s" aria-label = "Previous" >上一页</span></a></li>'.decode("utf-8") %
( self.base_url, urlencode(self.params))
page_html_list.append(pervious_page)
# 中间页码
for i in range(pager_start, pager_end + 1):
self.params['page'] = i
if i == self.current_page:
temp = '<li class="active"><a href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,)
else:
temp = '<li><a href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,)
page_html_list.append(temp)
self.params["page"] = self.current_page + 1
if self.params["page"] > self.max_page_num:
self.params["page"] = self.current_page
next_page = '<li class="disabled"><a href = "%s?%s" aria-label = "Next">下一页</span></a></li >'.decode
("utf-8") % (self.base_url, urlencode(self.params))
else:
next_page = '<li><a href = "%s?%s" aria-label = "Next">下一页</span></a></li>'.decode("utf-8") %
(self.base_url, urlencode(self.params))
page_html_list.append(next_page)
self.params['page'] = self.max_page_num
last_page = '<li><a href="%s?%s">尾页</a></li>'.decode("utf-8") % (self.base_url, urlencode(self.params),)
page_html_list.append(last_page)
return ''.join(page_html_list)自定义方法中的参数：
current_page——表示当前页。
total_count——表示数据总条数。
base_url——表示分页URL前缀，请求的前缀获取可以通过Flask的request.path方法，无需自己指定。
例如：我们的路由方法为@app.route('/test')，request.path方法即可获取/test。
params——表示请求传入的数据，params可以通过request.args动态获取。
例如：我们链接点击为：http://localhost:5000/test?page=10，此时request.args获取数据为ImmutableMultiDict([('page', u'10')])
per_page_count——指定每页显示数。
max_pager_count——指定页面显示页码
接着，我们使用一个测试方法来使用这个工具类，达到分页效果，test.py:
from flask import Flask, render_template, request
from page_utils import Pagination
app = Flask(__name__)
@app.route('/test')
def test():
li = []
for i in range(1, 100):
li.append(i)
pager_obj = Pagination(request.args.get("page", 1), len(li), request.path, request.args, per_page_count=10)
print(request.path)
print(request.args)
index_list = li[pager_obj.start:pager_obj.end]
html = pager_obj.page_html()
return render_template("obj/test.html", index_list=index_list, html=html)
if __name__ == '__main__':
app.run(debug=True)在上面的程序中，li为我们要分页的对象，数组list，我们获取到这个list之后，把他用工具类中的起止方法包起来。
传递数据用包装后的list，这样就达到了需要哪一段数据我们传递哪一段的效果，包装的方法：index_list = li[pager_obj.start:pager_obj.end]
我们用一个HTML页面去显示它，分页样式不是重点，我们这里直接引入bootstrap封装好的分页效果，代码如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="{{ url_for('static', filename='css/bootstrap.min.css') }}">
<style>
.container{
margin-top: 20px;
}
</style>
</head>
<body>
<div>
<div class="row " style="margin-top: 10px">
<ul>
{% for foo in index_list %}
<li>{{ foo }}：这是列表内容~~</li>
{% endfor %}
</ul>
<nav aria-label="Page navigation">
<ul>
{{ html|safe }}
</ul>
</nav>
</div>
</div>
</body>
</html>这样一个分页的效果就做好了，我们查看效果，如下图：
