# 属性错误：'Starlette'对象没有属性'add_middleware'

- **ID:** `python/starlette-attributeerror-starlette-app-has-no-attribute-add-middleware`
- **领域:** python
- **类别:** type_error
- **验证级别:** ai_generated
- **修复率:** 80%

## 根因

尝试在Starlette实例上使用add_middleware方法，但该方法在旧版本中不可用或对象错误。

## 版本兼容性

| 版本 | 状态 | 引入 | 弃用 |
|------|------|------|------|
| 3.x | active | — | — |

## 解决方案

1. **Use correct middleware registration syntax** (90% 成功率)
   ```
   app.add_middleware(MiddlewareClass)
   ```
2. **Check Starlette version and upgrade if needed** (85% 成功率)
   ```
   pip install --upgrade starlette
   ```

## 无效尝试

- **Assuming Starlette has the same API as Flask** — Starlette uses different middleware registration. (70% 失败率)
- **Using add_middleware on a middleware class instead of app** — Method exists on app, not middleware. (80% 失败率)