```Python hl_lines="1  3  7" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

### 🗄 `APIRouter`

🔜 👥 🗄 🎏 🔁 👈 ✔️ `APIRouter`Ⓜ:

```Python hl_lines="5" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

```Python hl_lines="1  3  7" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

### Den `APIRouter` importieren

Jetzt importieren wir die anderen Submodule, die `APIRouter` haben:

```Python hl_lines="4-5" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

## The main `FastAPI`

Now, let's see the module at `app/main.py`.

Here's where you import and use the class `FastAPI`.

This will be the main file in your application that ties everything together.

And as most of your logic will now live in its own specific module, the main file will be quite simple.

### Import `FastAPI`

因此，为了能够在同一个文件中使用它们，我们直接导入子模块：

```Python hl_lines="5" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

### 包含 `users` 和 `items` 的 `APIRouter`

现在，让我们来包含来自 `users` 和 `items` 子模块的 `router`。

```Python hl_lines="10-11" title="app/main.py"
{!../../../docs_src/bigger_applications/app/main.py!}
```

!!! info