django 分页器,序列化 ,MTV MVC

序列化组件
#
#     from django.core import serializers  # django自带的一个小型的序列化工具
#     def reg(request):
#        user_list = models.User.objects.all()
#        res = serializers.serialize('json',user_list)
#        return render(request,'index.html',locals())

sweetalert搭建页面
#
#  自定义分页器
#     1 bulk_create()  批量插入数据
#        # for i in range(1000):
#        #     models.Book.objects.create(title='第%s本书'%i)
#        # 上面这种方式 效率极低
#
#        l = []
#        for i in range(10000):
#           l.append(models.Book(title='第%s本书'%i))
#        models.Book.objects.bulk_create(l)  # 批量插入数据
#
#
#  自定义分页器的使用
#     后端代码
#           book_list = models.Book.objects.all()
#           current_page = request.GET.get("page",1)
#           all_count = book_list.count()
#           page_obj = Pagination(current_page=current_page,all_count=all_count,per_page_num=10,pager_count=5)
#           page_queryset = book_list[page_obj.start:page_obj.end]
#     前端代码
#           {% for book in page_queryset %}
#           <p>{{ book.title }}</p>
#           {% endfor %}
#           {{ page_obj.page_html|safe }}
#

#   MTV与MVC模型
#     django框架 自称为是MTV框架
#        M:models
#        T:templates
#        V:views
#
#     MVC
#        M:models
#        V:views
#        C:controller 控制器(urls)
#     本质:MTV其实也是MVC

from django.db import models

# Create your models here.
class User(models.Model):
    username = models.CharField(max_length=32)
    age = models.IntegerField()
    choices = (
        (1,'男'),(2,'女'),(3,'其他')
    )
    gender = models.IntegerField(choices=choices)

    """
    1 存choice里面罗列的数字与中文对应关系
         print(user_obj.get_gender_display())
            只要是choices字段 在获取数字对应的注释 固定语法
            get_choices字段名_display()

    2 存没有罗列迟来的数字
        不会报错 还是展示数字
    """


class Book(models.Model):
    title = models.CharField(max_length=32)

class Pagination(object):
    def __init__(self, current_page, all_count, per_page_num=2, pager_count=11):
        """
        封装分页相关数据
        :param current_page: 当前页
        :param all_count:    数据库中的数据总条数
        :param per_page_num: 每页显示的数据条数
        :param pager_count:  最多显示的页码个数

        用法:
        queryset = model.objects.all()
        page_obj = Pagination(current_page,all_count)
        page_data = queryset[page_obj.start:page_obj.end]
        获取数据用page_data而不再使用原始的queryset
        获取前端分页样式用page_obj.page_html
        """
        try:
            current_page = int(current_page)
        except Exception as e:
            current_page = 1

        if current_page < 1:
            current_page = 1

        self.current_page = current_page

        self.all_count = all_count
        self.per_page_num = per_page_num

        # 总页码
        all_pager, tmp = divmod(all_count, per_page_num)
        if tmp:
            all_pager += 1
        self.all_pager = all_pager

        self.pager_count = pager_count
        self.pager_count_half = int((pager_count - 1) / 2)

    @property
    def start(self):
        return (self.current_page - 1) * self.per_page_num

    @property
    def end(self):
        return self.current_page * self.per_page_num

    def page_html(self):
        # 如果总页码 < 11个：
        if self.all_pager <= self.pager_count:
            pager_start = 1
            pager_end = self.all_pager + 1
        # 总页码  > 11
        else:
            # 当前页如果<=页面上最多显示11/2个页码
            if self.current_page <= self.pager_count_half:
                pager_start = 1
                pager_end = self.pager_count + 1

            # 当前页大于5
            else:
                # 页码翻到最后
                if (self.current_page + self.pager_count_half) > self.all_pager:
                    pager_end = self.all_pager + 1
                    pager_start = self.all_pager - self.pager_count + 1
                else:
                    pager_start = self.current_page - self.pager_count_half
                    pager_end = self.current_page + self.pager_count_half + 1

        page_html_list = []
        # 添加前面的nav和ul标签
        page_html_list.append('''
                    <nav aria-label='Page navigation>'
                    <ul class='pagination'>
                ''')
        first_page = '<li><a href="?page=%s">首页</a></li>' % (1)
        page_html_list.append(first_page)

        if self.current_page <= 1:
            prev_page = '<li class="disabled"><a href="#">上一页</a></li>'
        else:
            prev_page = '<li><a href="?page=%s">上一页</a></li>' % (self.current_page - 1,)

        page_html_list.append(prev_page)

        for i in range(pager_start, pager_end):
            if i == self.current_page:
                temp = '<li class="active"><a href="?page=%s">%s</a></li>' % (i, i,)
            else:
                temp = '<li><a href="?page=%s">%s</a></li>' % (i, i,)
            page_html_list.append(temp)

        if self.current_page >= self.all_pager:
            next_page = '<li class="disabled"><a href="#">下一页</a></li>'
        else:
            next_page = '<li><a href="?page=%s">下一页</a></li>' % (self.current_page + 1,)
        page_html_list.append(next_page)

        last_page = '<li><a href="?page=%s">尾页</a></li>' % (self.all_pager,)
        page_html_list.append(last_page)
        # 尾部添加标签
        page_html_list.append('''
                                           </nav>
                                           </ul>
                                       ''')
        return ''.join(page_html_list)

from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

    initial = True

    dependencies = [
    ]

    operations = [
        migrations.CreateModel(
            name='User',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('username', models.CharField(max_length=32)),
                ('age', models.IntegerField()),
                ('gender', models.IntegerField(choices=[(1, '男'), (2, '女'), (3, '其他')])),
            ],
        ),
    ]

from __future__ import unicode_literals

from django.db import migrations, models


class Migration(migrations.Migration):

    dependencies = [
        ('app01', '0001_initial'),
    ]

    operations = [
        migrations.CreateModel(
            name='Book',
            fields=[
                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
                ('title', models.CharField(max_length=32)),
            ],
        ),
    ]