python使用flask实现前后端分离通过前端修改数据库数据【全栈开发基础】

文章目录

- 🚎前言：
- 🛺工具
- 🚓截图
- - 🚕数据库截图
  - 🚙前端截图
- 🚘代码
- - 🚲增加
  - - 🍕前端 HTML
    - 🍟后端 python
  - 🛴 删除
  - - 🍕前端 HTML
    - 🍟后端 python
  - 🛵 编辑
  - - 🍕前端 HTML
    - 🍟后端 python
  - 🛵 查看
  - - 🍕前端 HTML
    - 🍟后端 python
- 🥩 完整代码
- - 🥐前端 HTML
  - 🥨后端 python
- 结语

🚎前言：

完整代码放到了最后，时间紧张的话直接拉到最后或点击目录【🥩 完整代码】看完整代码

相信看过自己前期的博文python使用flask模块和前端交互基础以及python模块pymysql对数据库进行增删改查的小伙伴已经有了一定基础，这里我们在来对flask、pymsql、前端三个部分通过flask做一个整合。使用python来作为我们的后端来实现前后端的分离。
既然是作为基础，那我们这里主要实现通过前端对我们后端数据库实现增删改查就OK 了。下面我们开始。

🛺工具

后端：python（flask,pymsql）、MySQL、navicat、VScode
前端：VScode、Google浏览器

🚓截图

🚕数据库截图

这里的截图的是navicat，里面的id做了主键自增
在这里插入图片描述

🚙前端截图

前端上样式没有去做过多的修饰，只是做一个大概样式，有兴趣的也可以自己去用CSS修改一下
在这里插入图片描述

可视化截图就截图这两张吧，接下来就是代码了

🚘代码

这里先提一下，这个是需要下载MySQL数据库的，再有一些MySQL数据库的增删改查的代码学习基础。要不然有的代码可能是看不明白的哈，特别是数据库那一块的。restful风格这里对于增删改查使用了不同的方式

🚲增加

增加数据库这里用的也是基本和其它常见后端所用的那种方式，使用了post请求方法，对于前端不是从URL请求上携带的参数，我们都可以使用flask模块中的request的**get_dada()**方法来获取，至于如何取在URL上的数据，可以看下关于【🛴 删除】那里的简介。

🍕前端 HTML

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      border-bottom: 1px solid gray;
      padding-bottom: 10px;
    }

    table {
      width: 100%;
      text-align: center;
      border: solid 1px gray;
    }
  </style>
</head>

<body>
  <div id="add">
    <h3>新增数据</h3>
    姓名：<input type="text">
    年龄：<input type="text">
    专业：<input type="text">
    爱好：<input type="text">
    <button onclick="add()">提交</button>
  </div>
  <script>
    let xhr = new XMLHttpRequest(); //前端使用XMLHttpRequest创建的对象来访问后端
    const add = () => {
      let inputs = document.querySelectorAll("#add input");
      let addJson = {}
      addJson.name = inputs[0].value
      addJson.age = inputs[1].value
      addJson.major = inputs[2].value
      addJson.hobby = inputs[3].value
      // let res = ajax(,)
      xhr.open('post', 'http://localhost:8090/add', true)//最后一个参数表示是否异步请求
      xhr.send(JSON.stringify(addJson))
      xhr.onreadystatechange = () => {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText;
            isFirstRender = false
            alert(JSON.parse(res).msg);
            select()
          }
        }
      }
    }
  </script>
</body>

</html>

🍟后端 python

import pymysql
from flask import Flask,request
import json
from flask_cors import CORS
app = Flask(__name__)
CORS(app=app) # 跨域设置
app.debug=True # 开启debug模式
db = pymysql.connect(host='localhost',user='root',password='root',database='python') # 建立连接
cursor = db.cursor() #创建游标
@app.route('/add',methods=['post']) #设置请求头和请求方式
def add():
  req_data = request.get_data() # 获取data数据
  data = json.loads(req_data) # 需要使用json.loads来转换一下，返回的数据是字符码
  print(data)
  try:
    sql_data = (data['name'],int(data['age']),data['major'],data['hobby'])
    sql = "insert into userinfo(name,age,major,hobby) values (%s,%s,%s,%s)" #MySQL查询语句
    cursor.execute(sql,sql_data)
    db.commit()
    return {'code':200,'msg':'数据新增成功'}
  except:
    db.rollback()  # 发生错误时回滚 
    return {'code':1000,'msg':"添加失败"}
 if __name__ == '__main__':
  app.run(host="localhost",port='8090')
  cursor.close() #关闭游标
  db.close() # 关闭数据库连接

🛴 删除

删除使用的请求方式是delete。众所周知，前端发送给后端的数据要么在URL中，要么在请求体里面，这里的话，删除我就把数据放在了URL中，flask的request模块可以通过args.get()方法来接收前端放在URL中的数据。

🍕前端 HTML

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      border-bottom: 1px solid gray;
      padding-bottom: 10px;
    }

    table {
      width: 100%;
      text-align: center;
      border: solid 1px gray;
    }
  </style>
</head>

<body>
  
  <div id="del">
    <h3>根据姓名删除数据</h3>
    姓名：<input type="text">
    <button onclick="del()">删除</button>
  </div>
  <script>
    let xhr = new XMLHttpRequest();
    const del = () => {
      let input = document.querySelector("#del input");
      xhr.open('delete', 'http://localhost:8090/del?name=' + input.value, true)
      xhr.send()
      xhr.onreadystatechange = function () {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText
            isFirstRender = false
            alert(JSON.parse(res).msg);
            select()
          }
        }
      }
    }
  </script>
</body>
</html>

🍟后端 python

import pymysql
from flask import Flask,request
import json
from flask_cors import CORS
app = Flask(__name__)
CORS(app=app)
app.debug=True
db = pymysql.connect(host='localhost',user='root',password='root',database='python')
cursor = db.cursor() #创建游标
@app.route('/del',methods=['delete'])
def delete():
  deleteName = request.args.get('name')
  sql=f'delete from `userinfo` where name="{deleteName}";' # 删除数据的sql语句
  try:
    cursor.execute(sql)
    db.commit()
    return {'code':200,'msg':'删除成功'}
  except:
    db.rollback()  # 发生错误时回滚 
    return {'code':1000,'msg':"删除失败"}
 if __name__ == '__main__':
  app.run(host="localhost",port='8090')
  cursor.close() #关闭游标
  db.close() # 关闭数据库连接

🛵 编辑

修改数据这里就不多说了，直接看源码吧

🍕前端 HTML

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      border-bottom: 1px solid gray;
      padding-bottom: 10px;
    }

    table {
      width: 100%;
      text-align: center;
      border: solid 1px gray;
    }
  </style>
</head>

<body>
  <div id="edit">
    <h3>编辑数据</h3>
    <p>
      姓名：<input type="text" class="name" placeholder="请输入需要修改的姓名"> <input class="name" type="text" placeholder="请输入修改后的姓名">
      <button onclick="edit()">修改</button>
    </p>   
  </div>
  <script>
    let xhr = new XMLHttpRequest();
  const edit = () => {
      let names = document.querySelectorAll("#edit .name");
      let addJson = {}
      addJson.beforeName = names[0].value
      addJson.afterName = names[1].value
      xhr.open('put', 'http://localhost:8090/edit', true)
      xhr.send(JSON.stringify(addJson))
      xhr.onreadystatechange = function () {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText;
            isFirstRender = false
            alert(JSON.parse(res).msg);
            select()
          }
        }
      }
    }
  </script>
</body>
</html>

🍟后端 python

import pymysql
from flask import Flask,request
import json
from flask_cors import CORS
app = Flask(__name__)
CORS(app=app)
app.debug=True
db = pymysql.connect(host='localhost',user='root',password='root',database='python')
cursor = db.cursor() #创建游标
@app.route('/edit',methods=['put'])
def edit():
  req_data = request.get_data()
  data = json.loads(req_data)
  print('修改消息：',data)
  try:
    sql = f"update userinfo set name='{data['afterName']}' where name='{data['beforeName']}'"
    cursor.execute(sql)
    db.commit()
    return {'code':200,'msg':'修改成功'}
  except:
    db.rollback() 
    return {'code':1000,'msg':"修改失败"}
 if __name__ == '__main__':
  app.run(host="localhost",port='8090')
  cursor.close() #关闭游标
  db.close() # 关闭数据库连接

🛵 查看

🍕前端 HTML

查看数据这里需要注意一下，修改的数据是需要替换或者新增到我们的表里面，所以需要先删除掉原来的表再替换上新修改或增加的数据。有点前端基础的应该都清楚怎么做。

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      border-bottom: 1px solid gray;
      padding-bottom: 10px;
    }

    table {
      width: 100%;
      text-align: center;
      border: solid 1px gray;
    }
  </style>
</head>

<body>
  <div id="select">
    <h3>查询数据 <button onclick="select()">查询</button></h3>
    <table border cellspacing="0px" cellpading="0">
      <tr class="tableT">
        <th>ID</th>
        <th>姓名</th>
        <th>年龄</th>
        <th>专业</th>
        <th>爱好</th>
      </tr>
    </table>
  </div>
  <script>
    let xhr = new XMLHttpRequest();
 const select = () => {
      xhr.open('get', 'http://localhost:8090/select', true)
      xhr.send()
      xhr.onreadystatechange = () => {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText;
            let tdData = JSON.parse(res).data
            let tableT = document.querySelector("table");
            if(isFirstRender){

              tdData.forEach(element => {
                let tableB = document.createElement('tr')
                tableB.className = 'tableB'
                tableB.innerHTML = `
                <td>${element.id}</td>
                <td>${element.name}</td>
                <td>${element.age}</td>
                <td>${element.major}</td>
                <td>${element.hobby}</td>
                `
                tableT.appendChild(tableB)
              });
            }else{
              let delTableB = document.querySelectorAll('.tableB')
              for(let i = 0;i<delTableB.length;i++){
                tableT.removeChild(delTableB[i])
              }
              tdData.forEach(element => {
                let tableB = document.createElement('tr')
                tableB.className = 'tableB'
                tableB.innerHTML = `
                <td>${element.id}</td>
                <td>${element.name}</td>
                <td>${element.age}</td>
                <td>${element.major}</td>
                <td>${element.hobby}</td>
                `
                tableT.appendChild(tableB)
              });
            }
          }
        }
      }
    }
  </script>
</body>
</html>

🍟后端 python

import pymysql
from flask import Flask,request
import json
from flask_cors import CORS
app = Flask(__name__)
CORS(app=app)
app.debug=True
db = pymysql.connect(host='localhost',user='root',password='root',database='python')
cursor = db.cursor() #创建游标
@app.route('/select',methods=['get'])
def select():
  try:
    cursor.execute("SELECT * FROM userinfo")
    array = []
    data=()
    while isinstance(data,tuple):#循环遍历出data的数据
      data = cursor.fetchone() #fetchone方法用于取出数据库中查询的单个数据
      if(data == None): break
      obj = {}
      obj['id'] = data[0]
      obj['name'] = data[1]
      obj['age'] = data[2]
      obj['major'] = data[3]
      obj['hobby'] = data[4]
      array.append(obj)
    return {'code':200,'msg':'查询成功','data':array}
  except:
    db.rollback() 
    return {'code':1000,'msg':"查询失败"}
 if __name__ == '__main__':
  app.run(host="localhost",port='8090')
  cursor.close() #关闭游标
  db.close() # 关闭数据库连接

🥩 完整代码

🥐前端 HTML

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {
      border-bottom: 1px solid gray;
      padding-bottom: 10px;
    }

    table {
      width: 100%;
      text-align: center;
      border: solid 1px gray;
    }
  </style>
</head>

<body>
  <div id="select">
    <h3>查询数据 <button onclick="select()">查询</button></h3>
    <table border cellspacing="0px" cellpading="0">
      <tr class="tableT">
        <th>ID</th>
        <th>姓名</th>
        <th>年龄</th>
        <th>专业</th>
        <th>爱好</th>
      </tr>
    </table>
  </div>
  <div id="add">
    <h3>新增数据</h3>
    姓名：<input type="text">
    年龄：<input type="text">
    专业：<input type="text">
    爱好：<input type="text">
    <button onclick="add()">提交</button>
  </div>
 
  <div id="edit">
    <h3>编辑数据</h3>
    <p>
      姓名：<input type="text" class="name" placeholder="请输入需要修改的姓名"> <input class="name" type="text" placeholder="请输入修改后的姓名">
      <button onclick="edit()">修改</button>
    </p>   
  </div>
  <div id="del">
    <h3>根据姓名删除数据</h3>
    姓名：<input type="text">
    <button onclick="del()">删除</button>
  </div>
  <script>
    let xhr = new XMLHttpRequest();

    function ajax(methods, url, data) {
      xhr.open(methods, url, true)
      xhr.send(data)
      xhr.onreadystatechange = () => {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText;
            console.log(JSON.parse(res));
            return JSON.parse(res)
          }
        }
      }
    }
    let isFirstRender = true
    const add = () => {
      let inputs = document.querySelectorAll("#add input");
      let addJson = {}
      addJson.name = inputs[0].value
      addJson.age = inputs[1].value
      addJson.major = inputs[2].value
      addJson.hobby = inputs[3].value
      // let res = ajax(,)
      xhr.open('post', 'http://localhost:8090/add', true)
      xhr.send(JSON.stringify(addJson))
      xhr.onreadystatechange = () => {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText;
            isFirstRender = false
            alert(JSON.parse(res).msg);
            select()
          }
        }
      }
    }
    const edit = () => {
      let names = document.querySelectorAll("#edit .name");
      let addJson = {}
      addJson.beforeName = names[0].value
      addJson.afterName = names[1].value
      xhr.open('put', 'http://localhost:8090/edit', true)
      xhr.send(JSON.stringify(addJson))
      xhr.onreadystatechange = function () {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText;
            isFirstRender = false
            alert(JSON.parse(res).msg);
            select()
          }
        }
      }
    }
    const select = () => {
      xhr.open('get', 'http://localhost:8090/select', true)
      xhr.send()
      xhr.onreadystatechange = () => {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText;
            let tdData = JSON.parse(res).data
            let tableT = document.querySelector("table");
            if(isFirstRender){
              tdData.forEach(element => {
                let tableB = document.createElement('tr')
                tableB.className = 'tableB'
                tableB.innerHTML = `
                <td>${element.id}</td>
                <td>${element.name}</td>
                <td>${element.age}</td>
                <td>${element.major}</td>
                <td>${element.hobby}</td>
                `
                tableT.appendChild(tableB)
              });
            }else{
              let delTableB = document.querySelectorAll('.tableB')
              for(let i = 0;i<delTableB.length;i++){
                tableT.removeChild(delTableB[i])
              }
              tdData.forEach(element => {
                let tableB = document.createElement('tr')
                tableB.className = 'tableB'
                tableB.innerHTML = `
                <td>${element.id}</td>
                <td>${element.name}</td>
                <td>${element.age}</td>
                <td>${element.major}</td>
                <td>${element.hobby}</td>
                `
                tableT.appendChild(tableB)
              });
            }
          }
        }
      }
    }
    const del = () => {
      let input = document.querySelector("#del input");
      xhr.open('delete', 'http://localhost:8090/del?name=' + input.value, true)
      xhr.send()
      xhr.onreadystatechange = function () {
        if (xhr.readyState === 4) {
          if (xhr.status === 200) {
            let res = xhr.responseText
            isFirstRender = false
            alert(JSON.parse(res).msg);
            select()
          }
        }
      }
    }
  </script>
</body>

</html>

🥨后端 python

import pymysql
from flask import Flask,request
import json
from flask_cors import CORS
app = Flask(__name__)
CORS(app=app)
app.debug=True
db = pymysql.connect(host='localhost',user='root',password='root',database='python')
cursor = db.cursor() #创建游标
@app.route('/add',methods=['post'])
def add():
  req_data = request.get_data()
  data = json.loads(req_data)
  print(data)
  try:
    sql_data = (data['name'],int(data['age']),data['major'],data['hobby'])
    sql = "insert into userinfo(name,age,major,hobby) values (%s,%s,%s,%s)"
    cursor.execute(sql,sql_data)
    db.commit()
    return {'code':200,'msg':'数据新增成功'}
  except:
    db.rollback()  # 发生错误时回滚 
    return {'code':1000,'msg':"添加失败"}

@app.route('/del',methods=['delete'])
def delete():
  deleteName = request.args.get('name')
  sql=f'delete from `userinfo` where name="{deleteName}";'
  try:
    cursor.execute(sql)
    db.commit()
    return {'code':200,'msg':'删除成功'}
  except:
    db.rollback()  # 发生错误时回滚 
    return {'code':1000,'msg':"删除失败"}
@app.route('/edit',methods=['put'])
def edit():
  req_data = request.get_data()
  data = json.loads(req_data)
  print('修改消息：',data)
  try:
    sql = f"update userinfo set name='{data['afterName']}' where name='{data['beforeName']}'"
    cursor.execute(sql)
    db.commit()
    return {'code':200,'msg':'修改成功'}
  except:
    db.rollback() 
    return {'code':1000,'msg':"修改失败"}

@app.route('/select',methods=['get'])
def select():
  try:
    cursor.execute("SELECT * FROM userinfo")
    array = []
    data=()
    while isinstance(data,tuple):#循环遍历出data的数据
      data = cursor.fetchone() #fetchone方法用于取出数据库中查询的单个数据
      if(data == None): break
      obj = {}
      obj['id'] = data[0]
      obj['name'] = data[1]
      obj['age'] = data[2]
      obj['major'] = data[3]
      obj['hobby'] = data[4]
      array.append(obj)
    return {'code':200,'msg':'查询成功','data':array}
  except:
    db.rollback() 
    return {'code':1000,'msg':"查询失败"}
  
if __name__ == '__main__':
  app.run(host="localhost",port='8090')
  cursor.close()
  db.close()