flask+sqlite3+echarts2+ajax數據可視化

時間 2020-05-27

標籤 flask+sqlite3+echarts2+ajax flask sqlite echarts ajax 數據可視化欄目 Python 简体版

原文原文鏈接

前提：javascript

準備Python + Flask+Sqlite3的平臺環境(windows系統）html

前面一節介紹flask怎麼安裝了，剩下sqlite3下載後解壓，而後環境變量添加解壓路徑就好了java

附加下載地址：http://www.sqlite.org/2016/sqlite-tools-win32-x86-3150200.zipjquery

項目的目錄結構ajax

記得下載：echarts，echarts包含：數據庫

# create_db.py
# 只運行一次！！！

import sqlite3

# 鏈接
conn = sqlite3.connect('mydb.db')
c = conn.cursor()

# 建立表
c.execute('''DROP TABLE IF EXISTS weather''')
c.execute('''CREATE TABLE weather (month text, evaporation text, precipitation text)''')

# 數據
# 格式：月份,蒸發量,降水量
purchases = [(1, 2, 2.6),
             (2, 4.9, 5.9),
             (3, 7, 9),
             (4, 23.2, 26.4),
             (5, 25.6, 28.7),
             (6, 76.7, 70.7),
             (7, 135.6, 175.6),
             (8, 162.2, 182.2),
             (9, 32.6, 48.7),
             (10, 20, 18.8),
             (11, 6.4, 6),
             (12, 3.3, 2.3)
            ]

# 插入數據
c.executemany('INSERT INTO weather VALUES (?,?,?)', purchases)

# 提交！！！
conn.commit()

# 查詢方式一
for row in c.execute('SELECT * FROM weather'):
    print(row)
    
    
# 查詢方式二
c.execute('SELECT * FROM weather')
print(c.fetchall())


# 查詢方式二_2
res = c.execute('SELECT * FROM weather')
print(res.fetchall())


# 關閉
conn.close()

創建數據庫結果：json

     // index.html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>ECharts Ajax</title>
    <script src="{{ url_for('static', filename='jquery-1.6.2.js') }}"></script>
</head>

<body>
    <!--Step:1 爲ECharts準備一個具有大小（寬高）的Dom-->
    <div id="main" style="height:500px;border:1px solid #ccc;padding:10px;"></div>
    
    <!--Step:2 引入echarts.js-->
    <!--<script src="js/echarts.js"></script>-->
    <script src="{{ url_for('static', filename='echarts.js') }}"></script>
    
    <script type="text/javascript">
    // Step:3 爲模塊加載器配置echarts的路徑，從當前頁面連接到echarts.js，定義所需圖表路徑
    require.config({
        paths: {
            echarts: './static',
        }
    });
    
    // Step:4 動態加載echarts而後在回調函數中開始使用，注意保持按需加載結構定義圖表路徑
    require(
        [
            'echarts',
            'echarts/chart/bar', // 按需加載
            'echarts/chart/line',
        ],
        function (ec) {
            //--- 折柱 ---
            var myChart = ec.init(document.getElementById('main'));
            
            // 設置---------------------
            var option = {
                tooltip : {
                    trigger: 'axis'
                },
                legend: {
                    data:['蒸發量','降水量']
                },
                toolbox: {
                    show : true,
                    feature : {
                        mark : {show: true},
                        dataView : {show: true, readOnly: false},
                        magicType : {show: true, type: ['line', 'bar']},
                        restore : {show: true},
                        saveAsImage : {show: true}
                    }
                },
                calculable : true,
                xAxis : [
                    {
                        type : 'category',
                        data : []
                    }
                ],
                yAxis : [
                    {
                        type : 'value',
                        splitArea : {show : true}
                    }
                ],
                series : [
                    {
                        name:'蒸發量',
                        type:'bar',
                        data:[]
                    },
                    {
                        name:'降水量',
                        type:'line',
                        data:[]
                    }
                ]
            };
            
            $.ajax({
                cache: false,
                type: "POST",
                url: "/weather", //把表單數據發送到/weather
                data: null, // 發送的數據
                dataType : "json",  //返回數據形式爲json
                async: false,
                error: function(request) {
                    alert("發送請求失敗！");
                },
                success: function(result) {
                    //console.log(result);
                    for (i = 0, max = result.month.length; i < max; i++) { //注意：result.month.length
                        option.xAxis[0].data.push(result.month[i]);
                        option.series[0].data.push(parseFloat(result.evaporation[i])); 
                        option.series[1].data.push(parseFloat(result.precipitation[i])); 
                    };
                    
                    // 爲echarts對象加載數據-------------- 
                    myChart.setOption(option);
                }
            });
            // 爲echarts對象加載數據-------------- 
            //myChart.setOption(option);
        }
    );
    </script>    
</body>
</html>

# app.py

import sqlite3
from flask import Flask, request, render_template, jsonify

app = Flask(__name__)


def get_db():
    db = sqlite3.connect('mydb.db')
    db.row_factory = sqlite3.Row
    return db


def query_db(query, args=(), one=False):
    db = get_db()
    cur = db.execute(query, args)
    db.commit()
    rv = cur.fetchall()
    db.close()
    return (rv[0] if rv else None) if one else rv


@app.route("/", methods=["GET"])
def index():
    return render_template("index.html")


@app.route("/weather", methods=["POST"])
def weather():
    if request.method == "POST":
        res = query_db("SELECT * FROM weather")
    
    return jsonify(month = [x[0] for x in res],
                   evaporation = [x[1] for x in res], 
                   precipitation = [x[2] for x in res])


if __name__ == "__main__":
  app.run(debug=True)