Python-UV环境管理实战
Python-UV环境管理实战
Python使用Flask开发一个web应用实现数据的增改查，使用dict模拟数据库操作；个人实现代码仓库：https://gitee.com/enzoism/python_uv_hello-flask
1-UV从0开始构建环境
最好在Pycharm打开项目之前，先使用uv进行项目的环境指定->source .venv/bin/activate
# 1-查看并指定环境
uv python list
uv python pin 3.11.4# 2-进行项目创建
uv init hello-flask
cd hello-flask# 3-指定本地运行环境
uv venv
source .venv/bin/activate# 4-本地环境安装依赖
uv pip install flask2-Flask代码开发
下面给出一个最小可运行的示例，演示如何仅用 Python 内置 dict 作为“数据库”，通过 Flask 实现一套完整的「增-改-查（单条）-列表」接口，并附带一个极简的 HTML 页面，方便直接测试。复制即可运行，无需安装任何数据库。
- 安装依赖
# 建议使用虚拟环境
python -m venv venv
source venv/bin/activate # Windows 用 venv\Scripts\activate
pip install Flask==2.3.3
- 项目结构（单文件即可）
demo/├─ app.py # 所有代码放这里└─ templates/└─ index.html
- 代码实现
app.py
from flask import Flask, request, jsonify, render_template, abortapp = Flask(__name__)# ------------------------------
# 用 dict 模拟数据库
# key 为自增整数，value 为字典对象
# ------------------------------
db = {}
next_id = 1 # 自增主键# ------------------------------
# 路由：首页
# ------------------------------
@app.route('/')
def index():return render_template('index.html')# ------------------------------
# 接口：列表 + 条件查询
# ------------------------------
@app.route('/api/users', methods=['GET'])
def list_users():"""支持按 name 模糊查询例：/api/users?name=Tom"""name_filter = request.args.get('name', '').strip().lower()items = [{'id': uid, **info}for uid, info in db.items()if not name_filter or name_filter in info['name'].lower()]return jsonify(items)# ------------------------------
# 接口：单条查询
# ------------------------------
@app.route('/api/users/<int:uid>', methods=['GET'])
def get_user(uid):if uid not in db:abort(404, description=f"user {uid} not found")return jsonify({'id': uid, **db[uid]})# ------------------------------
# 接口：新增
# ------------------------------
@app.route('/api/users', methods=['POST'])
def create_user():global next_iddata = request.get_json(force=True)if not data or 'name' not in data:return jsonify({'error': "`name` field required"}), 400record = {'name': data['name'].strip(),'age': int(data.get('age', 0)),'city': data.get('city', '')}db[next_id] = recorduid = next_idnext_id += 1return jsonify({'id': uid, **record}), 201# ------------------------------
# 接口：修改（全量更新）
# ------------------------------
@app.route('/api/users/<int:uid>', methods=['PUT'])
def update_user(uid):if uid not in db:abort(404, description=f"user {uid} not found")data = request.get_json(force=True)if not data:return jsonify({'error': "empty payload"}), 400db[uid]['name'] = data.get('name', db[uid]['name']).strip()db[uid]['age'] = int(data.get('age', db[uid]['age']))db[uid]['city'] = data.get('city', db[uid]['city'])return jsonify({'id': uid, **db[uid]})# ------------------------------
# 接口：删除（可选）
# ------------------------------
@app.route('/api/users/<int:uid>', methods=['DELETE'])
def delete_user(uid):if uid not in db:abort(404, description=f"user {uid} not found")del db[uid]return '', 204# ------------------------------
# 错误处理
# ------------------------------
@app.errorhandler(404)
def not_found(err):return jsonify({'error': str(err.description)}), 404# ------------------------------
# 启动
# ------------------------------
if __name__ == '__main__':app.run(debug=True)
templates/index.html
<!doctype html>
<html>
<head><meta charset="utf-8"/><title>Flask + Dict CRUD</title><style>body{font-family:Arial,Helvetica,sans-serif;margin:40px}table{border-collapse:collapse;width:100%}th,td{border:1px solid #ccc;padding:6px 10px;text-align:left}input[type=text],input[type=number]{width:90%}</style>
</head>
<body><h2>用户管理（Flask + dict 版）</h2><h3>新增 / 修改</h3><form id="userForm"><input type="hidden" id="userId"/><br><label>姓名：<input type="text" id="name" required/></label><br><label>年龄：<input type="number" id="age" min="0"/></label><br><label>城市：<input type="text" id="city"/></label><br><button type="submit">保存</button><button type="button" onclick="resetForm()">重置</button><br></form><h3>用户列表</h3><input type="text" id="q" placeholder="按姓名模糊查询"/><button onclick="loadList()">搜索</button><table><thead><tr><th>ID</th><th>姓名</th><th>年龄</th><th>城市</th><th>操作</th></tr></thead><tbody id="list"></tbody></table><script>
const API = '/api/users';
function resetForm(){document.getElementById('userForm').reset();document.getElementById('userId').value='';
}
async function loadList(){const q=document.getElementById('q').value.trim();const res=await fetch(API+(q?`?name=${q}`:''));const data=await res.json();const html=data.map(u=>`<tr><td>${u.id}</td><td>${u.name}</td><td>${u.age}</td><td>${u.city}</td><td><button onclick="editUser(${u.id},'${u.name}',${u.age},'${u.city}')">改</button><button onclick="delUser(${u.id})">删</button></tr>`).join('');document.getElementById('list').innerHTML=html;
}
function editUser(id,name,age,city){document.getElementById('userId').value=id;document.getElementById('name').value=name;document.getElementById('age').value=age;document.getElementById('city').value=city;
}
async function delUser(id){await fetch(`${API}/${id}`,{method:'DELETE'});loadList();
}
document.getElementById('userForm').addEventListener('submit',async e=>{e.preventDefault();const id=document.getElementById('userId').value;const payload={name:document.getElementById('name').value.trim(),age:Number(document.getElementById('age').value),city:document.getElementById('city').value.trim()};const url=id?`${API}/${id}`:API;const method=id?'PUT':'POST';await fetch(url,{method,headers:{'Content-Type':'application/json'},body:JSON.stringify(payload)});resetForm();loadList();
});
// 初始化
loadList();
</script>
</body>
</html>
- 运行 & 验证
python app.py
# 默认 http://127.0.0.1:5000
打开浏览器即可进行「新增/查询/修改/删除」操作。所有数据仅保存在内存 dict 中，重启进程即清空。