python之flask框架：
flask图标
简介
Flask是一个轻量级的基于Python的web框架。
Flask是一个轻量级的可定制框架，使用Python语言编写，较其他同类型框架更为灵活、轻便、安全且容易上手。它可以很好地结合MVC模式进行开发，开发人员分工合作，小型团队在短时间内就可以完成功能丰富的中小型网站或Web服务的实现。另外，Flask还有很强的定制性，用户可以根据自己的需求来添加相应的功能，在保持核心功能简单的同时实现功能的丰富与扩展，其强大的插件库可以让用户实现个性化的网站定制，开发出功能强大的网站。
优势
一、后续的基于机器学习的车辆检测与属性识别算法研究，主要开发语言也是应用Python，整个系统统一开发语言，便于开发和后期维护。
二、Flask因为灵活、轻便且高效的特点被业界认可，同时拥有基于Werkzeug、Jinja2等一些开源库，拥有内置服务器和单元测试，适配RESTful，支持安全的cookies，而且官方文档完整，便于学习掌握。
三、Flask中拥有灵活的Jinja2模板引擎，提高了前端代码的复用率。这样可以提高开发效率和有利于后期开发与维护。在现有标准中，Flask算是微小型框架。Flask有两个主要依赖：路由、调试和Web服务器网关接口（WebServerGatewayInterface，WSGI）子系统由Werkzeug提供；模板系统由Jinja2提供。Werkzeug和Jinja2都是由Flask的核心开发者开发而成。对于数据库访问、验证Web表单和用户身份认证等一系列功能，Flask框架是不支持的。这些功能都是以扩展组件的方式进行实现，然后再与Flask框架集成。开发者可以根据项目的需求进行相应的扩展，或者自行开发。这与大型框架恰恰相反，大型框架本身做出了大部分决定，难以灵活改变方案。
其他框架
Django的主要目的是简便、快速的开发数据库驱动的网站。它强调代码复用，多个组件可以很方便的以“插件”形式服务于整个框架，Django有许多功能强大的第三方插件，你甚至可以很方便的开发出自己的工具包。这使得Django具有很强的可扩展性。它还强调快速开发和DRY(Do Not Repeat Yourself)原则。
框架目录结构
默认配置
static和templates目录是默认配置，其中static用来存放静态资源，例如图片、js、css文件等。templates存放模板文件。
我们的网站逻辑基本在server.py文件中，当然，也可以给这个文件起其他的名字。
flask的目录包括以上这种框架，所谓static里就是放数据和渲染的文件，比如.csv，.txt，.css，.js，数据以及图片和视频。
templates，模板，就是HTML模板，放置HTML的地方。
app.py:flask运行的主程序
其他.py 蓝图，就是具备app.py的后端程序功能，但不是主程序，叫做蓝图
----app.py----
from flask import Flask, render_template
import news as news, products as products # 导入相应模块
app = Flask(__name__) # 创建 Flask()对象： app
@app.route('/') # 使用了蓝图，app.route() 这种模式就仍可以使用，注意路由重复的问题
def hello_world(): # 定义函数
return render_template('index.html')
app.register_blueprint(news.new_list) # 将news模块里的蓝图对象new_list注册到app
app.register_blueprint(products.product_list) # 将products模块里的蓝图对象product_list注册到app
if __name__ == '__main__':
app.run(host='127.0.0.1',port=8082, debug=True) # 调试模式开 启动服务器 运行在默认的5000端口
-----蓝图------
- news(新闻界面蓝图)
from flask import Blueprint # 导入Blueprint模块
from flask import Flask, render_template, request # 导入相应模块
new_list = Blueprint('news', __name__) # 创建一个blueprint对象。第一个参数可看做该blueprint对象的姓名
# 在一个app里，姓名不能与其余的Blueprint对象姓名重复
# 第二个参数__name__用作初始化
@new_list.route("/login", methods=['GET', 'POST']) # 将蓝图对象当做‘app’那样使用
# def new(): # 定义函数news()
#
def login(): # 定义视图函数
k = int(request.form.get('name'))
b = int(request.form.get('password'))
from pyecharts.charts import Line
import pyecharts.options as opts
import numpy as np
x = np.linspace(0, 2 * np.pi, 100)
y = k*x + b
(Line(init_opts=opts.InitOpts(width="700px", height="300px"))
.add_xaxis(xaxis_data=x)
.add_yaxis(series_name="绘制线图", y_axis=y, label_opts=opts.LabelOpts(is_show=False))
.set_global_opts(
title_opts=opts.TitleOpts(title="我是标题", subtitle="我是副标题", title_link="https://www.baidu.com/"),
tooltip_opts=opts.TooltipOpts(axis_pointer_type="cross"))
).render('templates/news.html')
return render_template('news.html',**locals())
-----蓝图------
2. products(产品蓝图)
from flask import Blueprint # 导入Blueprint模块
from flask import Flask,render_template,request,redirect,url_for
from werkzeug.utils import secure_filename
import os
product_list = Blueprint('products', __name__) # 创建一个blueprint对象。第一个参数可看做该blueprint对象的名字
# 在一个app里，对象名不能与其余的Blueprint对象名重复
# 第二个参数__name__用作初始化
@product_list.route("/products", methods=['POST', 'GET']) # 将蓝图对象当做‘app’那样使用
def product():
if request.method == 'POST':
f = request.files['file']
basepath = os.path.dirname(__file__) # 当前文件所在路径
upload_path = os.path.join(basepath, 'static/dataes',secure_filename(f.filename)) #注意：没有的文件夹一定要先创建，不然会提示没有该路径
f.save(upload_path)
import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sns
plt.switch_backend('agg')
sns.set(style='whitegrid', context='notebook') # style控制默认样式,context控制着默认的画幅大小
plt.rcParams['font.sans-serif'] = ['Microsoft YaHei']
df = pd.read_csv('static/dataes/kaggle.csv') # 指你要用哪些列的数据
df_corr=df.corr()
sns.heatmap(df.corr(), annot=True, vmax=1, square=True, cmap="Blues")
plt.savefig('static/images/heatmap.png')
return render_template('products.html',**locals())
—templates(模板)—
index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8"><!--指定网页编码-->
<title>Title</title><!--指定网页标题-->
<style type="text/css">
.div1 {
height:180px;
width:380px;
border:1px solid #8A8989;
margin:0 auto;
}
.input{
display: block;
width: 350px;
height: 40px;
margin: 10px auto;
}
.button
{
background: #2066C5;
color: white;
font-size: 18px;
font-weight: bold;
height: 50px;
border-radius: 4px;
}
</style>
</head><!--head区域完毕-->
<body><!--body区域开始-->
<h3 style="text-align:center">输入y=kx+b形式函数</h3>
<div class="div1"><form action="login" method = "post"><!--定义表单开始-->
<input type="number" class="input" name="name" placeholder="请输入回归系数"><!--输入文本框-->
<input type="number" class="input" name="password" placeholder="请输入回归截距"><!--输入文本框-->
<input type="submit" value="输出" class="input button" ><!--定义登陆用button-->
</form></div> <!--form表单结束-->
</body><!--body区域完毕-->
</html>
news.html
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Awesome-pyecharts</title>
<script type="text/javascript" src="https://assets.pyecharts.org/assets/echarts.min.js"></script>
</head>
<body>
<div id="843fff3599974719a844a2289e4b73ff" class="chart-container" style="width:700px; height:300px;"></div>
<script>
var chart_843fff3599974719a844a2289e4b73ff = echarts.init(
document.getElementById('843fff3599974719a844a2289e4b73ff'), 'white', {renderer: 'canvas'});
var option_843fff3599974719a844a2289e4b73ff = {
"animation": true,
"animationThreshold": 2000,
"animationDuration": 1000,
"animationEasing": "cubicOut",
"animationDelay": 0,
"animationDurationUpdate": 300,
"animationEasingUpdate": "cubicOut",
"animationDelayUpdate": 0,
"color": [
"#c23531",
"#2f4554",
"#61a0a8",
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"#ca8622",
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"#546570",
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"#f05b72",
"#ef5b9c",
"#f47920",
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"#b2d235",
"#6d8346",
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"#6950a1",
"#918597"
],
"series": [
{
"type": "line",
"name": "\u7ed8\u5236\u7ebf\u56fe",
"connectNulls": false,
"symbolSize": 4,
"showSymbol": true,
"smooth": false,
"clip": true,
"step": false,
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"triggerOn": "mousemove|click",
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"xAxis": [
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"title": [
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"link": "https://www.baidu.com/",
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"itemGap": 10
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};
chart_843fff3599974719a844a2289e4b73ff.setOption(option_843fff3599974719a844a2289e4b73ff);
</script>
</body>
</html>
products.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<h1>heatmap热力图显示以及计算</h1>
<form action="" enctype='multipart/form-data' method='POST'>
<input type="file" name="file">
<input type="submit" value="上传">
</form>
<img src="static/images/heatmap.png">
<br>
{% for k,v in df_corr.items() %}
{{ v}}<br>
{% endfor %}
</body>
</html>
效果展示
