django之session与分页(实例讲解)
前面我们介绍了cookies，主要应用在用户登录上，保存用户登录状态，不过cookies直接放在了浏览器上，安全性较低，所以我们便引出了session功能与cookies相同，不同的是它放在了客户端，相比较cookies来说安全性更高。还有分页，这是一个比较常用的功能。
一、session
1、基本语法：
1、设置Sessions值
request.session['session_name'] ="admin"
2、获取Sessions值
session_name = request.session["session_name"]
session_name = request.session.get("session_name")
3、删除Sessions值
del request.session["session_name"]
request.session.flush()
4、检测是否操作session值
if "session_name" is request.session :
2、解析图
3、实例
1）views
def login(requset):
if requset.method=="POST":
username=requset.POST.get("user")
password=requset.POST.get("pwd")
ret=models.UserInfo.objects.filter(username=username,password=password)
if ret:
requset.session["IS_LOGON"]=True
requset.session["USER"]=username
return redirect("/home/")
else:
return redirect("/login/")
return render(requset,"login.html")
def home(request):
ret=request.session.get("IS_LOGON",None)
if ret :
username=request.session.get("USER")
return render(request, "home.html",locals())
else:
return redirect("/login/")
2）template
<form action="/login/" method="post">
{% csrf_token %}
<p>姓名 <input type="text" name="user"></p>
<p>密码 <input type="password" name="pwd"></p>
<input type="submit">
</form>
二、分页
1、view
from django.shortcuts import render,HttpResponse
# Create your views here.
from app01.models import *
from django.core.paginator import Paginator, EmptyPage, PageNotAnInteger
def index(request):
'''
批量导入数据:
Booklist=[]
for i in range(100):
Booklist.append(Book(title="book"+str(i),price=30+i*i))
Book.objects.bulk_create(Booklist)
'''
'''
分页器的使用:
book_list=Book.objects.all()
paginator = Paginator(book_list, 10)
print("count:",paginator.count) #数据总数
print("num_pages",paginator.num_pages) #总页数
print("page_range",paginator.page_range) #页码的列表
page1=paginator.page(1) #第1页的page对象
for i in page1: #遍历第1页的所有数据对象
print(i)
print(page1.object_list) #第1页的所有数据
page2=paginator.page(2)
print(page2.has_next()) #是否有下一页
print(page2.next_page_number()) #下一页的页码
print(page2.has_previous()) #是否有上一页
print(page2.previous_page_number()) #上一页的页码
# 抛错
#page=paginator.page(12) # error:EmptyPage
#page=paginator.page("z") # error:PageNotAnInteger
'''
book_list=Book.objects.all()
paginator = Paginator(book_list, 10)
page = request.GET.get('page',1)
currentPage=int(page)
try:
print(page)
book_list = paginator.page(page)
except PageNotAnInteger:
book_list = paginator.page(1)
except EmptyPage:
book_list = paginator.page(paginator.num_pages)
return render(request,"index.html",{"book_list":book_list,"paginator":paginator,"currentPage":currentPage})
2、templates
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="external nofollow"
integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u" crossorigin="anonymous">
</head>
<body>
<div class="container">
<h4>分页器</h4>
<ul>
{% for book in book_list %}
<li>{{ book.title }} -----{{ book.price }}</li>
{% endfor %}
</ul>
<ul class="pagination" id="pager">
{% if book_list.has_previous %}
<li class="previous"><a href="/index/?page={{ book_list.previous_page_number }}" rel="external nofollow" >上一页</a></li>
{% else %}
<li class="previous disabled"><a href="#" rel="external nofollow" rel="external nofollow" >上一页</a></li>
{% endif %}
{% for num in paginator.page_range %}
{% if num == currentPage %}
<li class="item active"><a href="/index/?page={{ num }}" rel="external nofollow" rel="external nofollow" >{{ num }}</a></li>
{% else %}
<li class="item"><a href="/index/?page={{ num }}" rel="external nofollow" rel="external nofollow" >{{ num }}</a></li>
{% endif %}
{% endfor %}
{% if book_list.has_next %}
<li class="next"><a href="/index/?page={{ book_list.next_page_number }}" rel="external nofollow" >下一页</a></li>
{% else %}
<li class="next disabled"><a href="#" rel="external nofollow" rel="external nofollow" >下一页</a></li>
{% endif %}
</ul>
</div>
</body>
</html>
3、扩展
def index(request):
book_list=Book.objects.all()
paginator = Paginator(book_list, 15)
page = request.GET.get('page',1)
currentPage=int(page)
# 如果页数十分多时，换另外一种显示方式
if paginator.num_pages>30:
if currentPage-5<1:
pageRange=range(1,11)
elif currentPage+5>paginator.num_pages:
pageRange=range(currentPage-5,paginator.num_pages+1)
else:
pageRange=range(currentPage-5,currentPage+5)
else:
pageRange=paginator.page_range
try:
print(page)
book_list = paginator.page(page)
except PageNotAnInteger:
book_list = paginator.page(1)
except EmptyPage:
book_list = paginator.page(paginator.num_pages)
return render(request,"index.html",locals())
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