• Flask 框架实现自定义分页


    手撸的表格分页: Flask框架下的分页,我研究了很久,自带的分页方法不稳定,还不如自己手撸的好使.

    <!--name:ndex.html-->
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
    </head>
    <body>
    <table class="table table-sm table-hover">
        <thead>
            <tr class="table-success">
                <th> 序号</th> <th> 用户ID</th> <th> 用户名称</th> <th> 用户邮箱</th>
            </tr>
        </thead>
        <tbody>
            {% for article in articles %}
                <tr class="table-primary">
                    <td>{{ loop.index }}</td>
                    <td>{{ article.id }}</td>
                    <td>{{ article.name }}</td>
                    <td>{{ article.email }}</td>
                </tr>
            {% endfor %}
        </tbody>
    </table>
    <nav class="d-flex justify-content-center" aria-label="Page navigation example">
      <ul class="pagination">
        <li class="page-item"><a class="page-link" href="./page=1">首页</a></li>
          {% if pagination.has_prev %}
               <li class="page-item"><a class="page-link" href="./page={{ prve_num }}">上一页</a></li>
          {% endif %}
    
    <!--获取当前列表,并全部填充到这里-->
          {% for  item in PageList %}
              {% if item == 0 %} <!--判断如果为0,则说明是选中页面,直接标号为当前页码-->
                    <li class="page-item active"><a class="page-link" href="./page={{ pagination.page }}">{{ pagination.page }}</a></li>
              {% else %} <!--否则的话,就直接接收参数填充-->
                    <li class="page-item"><a class="page-link" href="./page={{ item }}">{{ item }}</a></li>
              {% endif %}
          {% endfor %}
    
          {% if next_end %}
              <li class="page-item"><a class="page-link" href="./page={{ next_num }}">下一页</a></li>
          {% endif %}
        <li class="page-item"><a class="page-link" href="./page={{ PageCount }}">尾页</a></li>
      </ul>
    </nav>
      <div style="text-align: center;" class="alert alert-dark">
       统计: {{ pagination.page }}/{{ PageCount }} 共查询到:{{ pagination.total }} 条数据</div>
    </body>
    </html>
    

    app.py

    # name:app.py
    from flask import Flask,render_template,request
    from flask_sqlalchemy import SQLAlchemy
    from flask_paginate import Pagination,get_page_parameter
    import sqlalchemy,sqlite3,math
    
    app = Flask(__name__)
    app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///d:/user.db'
    # 设置每次请求结束后会自动提交数据库的改动
    app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True
    # 查询时显示原始SQL语句
    app.config['SQLALCHEMY_ECHO'] = False
    db = SQLAlchemy(app)
    
    class User(db.Model):
        __tablename__="user"          # 定义表名称
        id = db.Column(db.Integer,primary_key=True)  # 映射数据库字段
        name = db.Column(db.String(32))
        email = db.Column(db.String(32))
        def __init__(self,name,email):
            self.name=name
            self.email=email
        def __repr_(self):
            return 'User %s'%self.name
    
    @app.route("/")
    def index():
        return """<script>window.location.href="./page=1"</script>"""
    
    @app.route("/page=<int:id>")
    def GetPages(id):
        PER_PAGE = 3   # 默认每页显示3个元素
        total = db.session.query(User).count()
        print("总记录 {} 条".format(total))
        page = request.args.get(get_page_parameter(),type=int,default=int(id))
        print("当前页码ID为 {}".format(page))
        start = (page-1)*PER_PAGE   # 分页起始位置
        end = start+PER_PAGE        # 分页结束位置
        print("起始位置 {} 结束位置 {}".format(start,end))
    
        prev_num = int(page)-1
        next_num = int(page)+1
        print("上一页页码 {} 下一页页码 {}".format(prev_num,next_num))
    
        page_count = math.ceil(total/PER_PAGE)              # 计算出需要切割的页数
        print("切割页数 {}".format(page_count))
    
        pagination = Pagination(page=page,total=total)
        articles = db.session.query(User).slice(start,end)  # 执行数据库切片
    
        if page>=math.ceil(total/PER_PAGE):   # 判断,如果next_end大于总数说明到最后了
            next_end=0                        # 那么我们就将next_end设置为0,前端就不执行显示了.
        else:
            next_end=1
        # ---------------------------------------------
        # 功能拓展,用于生成当前页码.
        page_list = []
        for i in range(1, page_count + 1):
            if i == page:
                page_list.append(0)    # 赋值为0说明是当前页面
            else:                      # 否则就直接赋值元素
                page_list.append(i)
        print("生成的当前页码: {}".format(page_list))
    
        context = {
            'pagination': pagination,
            'articles': articles,
            'prve_num': prev_num,
            'next_num': next_num,
            'PageCount': page_count,
            'PageList': page_list,
            'next_end': next_end
        }
        return render_template('index.html',**context)
    
    if __name__ == '__main__':
        app.run()
    

    一个优秀的表格分页: 在网上摘抄的优秀的分页类,我对其进行稍微美化,并加上数据库过程,很nice.

    <!-- name: page.html-->
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>Title</title>
        <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
    </head>
    <body>
    <table class="table table-sm table-hover">
        <thead>
            <tr class="table-success">
                <th> 用户ID</th>
                <th> 用户名称</th>
                <th> 用户邮箱</th>
            </tr>
        </thead>
        <tbody>
            {% for article in articles %}
                <tr class="table-primary">
                    <td>{{ article.id }}</td>
                    <td>{{ article.name }}</td>
                    <td>{{ article.email }}</td>
                </tr>
            {% endfor %}
        </tbody>
    </table>
        <nav class="d-flex justify-content-center" aria-label="Page navigation example">
             <ul class="pagination">
                {{ html|safe }}
            </ul>
        </nav>
    </body>
    </html>
    

    pager.py

    # name:pager.py
    
    import copy
    from urllib.parse import urlencode,quote,unquote
    
    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
            # 数据总条数
            self.total_count = total_count
            # 每页显示10条数据
            self.per_page_count = per_page_count
            # 页面上应该显示的最大页码
            max_page_num, div = divmod(total_count, per_page_count)
            if div:
                max_page_num += 1
            self.max_page_num = max_page_num
            # 页面上默认显示11个页码(当前页在中间)
            self.max_pager_count = max_pager_count
            self.half_max_pager_count = int((max_pager_count - 1) / 2)
            # URL前缀
            self.base_url = base_url
            # request.GET
            params = copy.deepcopy(params)
            # params._mutable = True
            get_dict = params.to_dict()
            # 包含当前列表页面所有的搜/索条件
            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):
            # 如果总页数 <= 11
            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:
                # 如果当前页 <= 5
                if self.current_page <= self.half_max_pager_count:
                    pager_start = 1
                    pager_end = self.max_pager_count
                else:
                    # 当前页 + 5 > 总页码
                    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 = []
            # 首页
            self.params['page'] = 1
            first_page = '<li class="page-item"><a class="page-link" href="%s?%s">首页</a></li>' % (self.base_url,urlencode(self.params),)
            page_html_list.append(first_page)
            # 上一页
            self.params["page"] = self.current_page - 1
            if self.params["page"] < 1:
                pervious_page = '<li class="page-item" class="disabled"><a class="page-link" 
                href="%s?%s" aria-label="Previous">上一页</span></a></li>' % (self.base_url, urlencode(self.params))
            else:
                pervious_page = '<li class="page-item"><a class="page-link" href = "%s?%s" 
                aria-label = "Previous" >上一页</span></a></li>' % ( 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="page-item active" class="active"><a class="page-link" 
                    href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,)
                else:
                    temp = '<li  class="page-item"><a class="page-link" 
                    href="%s?%s">%s</a></li>' % (self.base_url,urlencode(self.params), i,)
                page_html_list.append(temp)
            # 下一页
            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="page-item" class="disabled"><a class="page-link" 
                href = "%s?%s" aria-label = "Next">下一页</span></a></li >' % (self.base_url, urlencode(self.params))
            else:
                next_page = '<li class="page-item"><a class="page-link" href = "%s?%s" 
                aria-label = "Next">下一页</span></a></li>' % (self.base_url, urlencode(self.params))
            page_html_list.append(next_page)
            # 尾页
            self.params['page'] = self.max_page_num
            last_page = '<li class="page-item"><a class="page-link" href="%s?%s">尾页</a></li>' % (self.base_url, urlencode(self.params),)
            page_html_list.append(last_page)
            return ''.join(page_html_list)
    

    app.py

    # name:app.py
    
    from flask import Flask,render_template,request,redirect
    from pager import Pagination          #带入分页类
    from urllib.parse import urlencode
    from flask_sqlalchemy import SQLAlchemy
    import sqlalchemy,sqlite3,math
    
    app = Flask(__name__)
    app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///d:/user.db'
    # 设置每次请求结束后会自动提交数据库的改动
    app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True
    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = True
    # 查询时显示原始SQL语句
    app.config['SQLALCHEMY_ECHO'] = False
    db = SQLAlchemy(app)
    
    class User(db.Model):
        __tablename__="user"          # 定义表名称
        id = db.Column(db.Integer,primary_key=True)  # 映射数据库字段
        name = db.Column(db.String(32))
        email = db.Column(db.String(32))
        def __init__(self,name,email):
            self.name=name
            self.email=email
        def __repr_(self):
            return 'User %s'%self.name
    
    @app.route("/")
    def hello():
    # current_page—: 表示当前页
    # total_count—: 数据总条数
    # base_url: 分页URL前缀,通过request.path方法获取
    # params: 请求传入的数据params可以通过request.args动态获取
    # per_page_count :指定每页显示数
    # max_pager_count: 指定页面最大显示页码
        total = db.session.query(User).count()
        Page = Pagination(request.args.get("page", 1), total, request.path, request.args, per_page_count=5)
        index_list = db.session.query(User)[Page.start:Page.end]
        html = Page.page_html()
        return render_template("page.html",articles=index_list,html=html)
    
    if __name__ == '__main__':
        app.run(debug=True)
    

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  • 原文地址:https://www.cnblogs.com/LyShark/p/12074086.html
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