django 分页器,序列化 ,MTV MVC

水深无声 2023-08-17 15:21 88阅读 0赞

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)),
                ],
            ),
        ]

转载于:https://www.cnblogs.com/Sunbreaker/p/11574776.html