import org.apache.maven.api.model.Repository;
import org.apache.maven.api.model.Resource;
import org.apache.maven.model.Model;
import org.apache.maven.model.building.ModelBuildingRequest;
import org.apache.maven.model.building.ModelProblem.Severity;
import org.apache.maven.model.building.ModelProblem.Version;
import org.apache.maven.model.building.ModelProblemCollector;
import org.apache.maven.model.building.ModelProblemCollectorRequest;

    full_name = user_dict["full_name"],
    disabled = user_dict["disabled"],
    hashed_password = user_dict["hashed_password"],
)
```

/// info | "说明"

`user_dict` 的说明，详见[**更多模型**一章](../extra-models.md#user_indict){.internal-link target=_blank}。

///

## 返回 Token

`token` 端点的响应必须是 JSON 对象。

响应返回的内容应该包含 `token_type`。本例中用的是**Bearer**Token，因此， Token 类型应为**`bearer`**。

    * Convert Python types (`str`, `int`, `float`, `bool`, `list`, etc).
    * `datetime` objects.
    * `UUID` objects.
    * Database models.
    * ...and many more.
* Automatic interactive API documentation, including 2 alternative user interfaces:
    * Swagger UI.
    * ReDoc.

---

Coming back to the previous code example, **FastAPI** will:

inside and make sure it is serializable as JSON, using the same [JSON Compatible Encoder](../tutorial/encoder.md){.internal-link target=_blank} explained in the tutorial. This is what allows you to return **arbitrary objects**, for example database models.

But if you are certain that the content that you are returning is **serializable with JSON**, you can pass it directly to the response class and avoid the extra overhead that FastAPI would have by passing your return content through the...

    * Converte tipos Python (`str`, `int`, `float`, `bool`, `list` etc).
    * Objetos `datetime`.
    * Objetos `UUID`.
    * Modelos de Banco de Dados.
    * ...e muito mais.
* Documentação interativa automática da API, incluindo 2 alternativas de interface de usuário:
    * Swagger UI.
    * ReDoc.

---

    * Convertir tipos de Python (`str`, `int`, `float`, `bool`, `list`, etc).
    * Objetos `datetime`.
    * Objetos `UUID`.
    * Modelos de bases de datos.
    * ...y muchos más.
* Documentación automática e interactiva incluyendo 2 interfaces de usuario alternativas:
    * Swagger UI.
    * ReDoc.

---

```

////

/// tip

Pydantic, ❔ ⚫️❔ 🏋️ 🌐 💽 🔬 &amp; 🛠️ FastAPI, ✔️ 🎁 🎭 🕐❔ 👆 ⚙️ `Optional` ⚖️ `Union[Something, None]` 🍵 🔢 💲, 👆 💪 ✍ 🌅 🔃 ⚫️ Pydantic 🩺 🔃 <a href="https://docs.pydantic.dev/latest/concepts/models/#required-optional-fields" class="external-link" target="_blank">✔ 📦 🏑</a>.

///

### ⚙️ Pydantic `Required` ↩️ ❕ (`...`)

🚥 👆 💭 😬 ⚙️ `...`, 👆 💪 🗄 &amp; ⚙️ `Required` ⚪️➡️ Pydantic:

	github.com/goccy/go-json v0.10.3 // indirect
	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
	github.com/google/btree v1.1.2 // indirect
	github.com/google/gnostic-models v0.6.8 // indirect
	github.com/google/pprof v0.0.0-20240827171923-fa2c70bbbfe5 // indirect
	github.com/grafana/regexp v0.0.0-20240518133315-a468a5bfb3bc // indirect

```

/// tip

Pydantic 是 FastAPI 中所有数据验证和序列化的核心，当你在没有设默认值的情况下使用 `Optional` 或 `Union[Something, None]` 时，它具有特殊行为，你可以在 Pydantic 文档中阅读有关<a href="https://docs.pydantic.dev/latest/concepts/models/#required-optional-fields" class="external-link" target="_blank">必需可选字段</a>的更多信息。

///

### 使用Pydantic中的`Required`代替省略号(`...`)

如果你觉得使用 `...` 不舒服，你也可以从 Pydantic 导入并使用 `Required`：

```Python hl_lines="2  8"

  |   definition of these types
  |
-->
<model xmlns="http://codehaus-plexus.github.io/MODELLO/2.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://codehaus-plexus.github.io/MODELLO/2.0.0 https://codehaus-plexus.github.io/modello/xsd/modello-2.0.0.xsd"
  xml.namespace="http://maven.apache.org/POM/${version}"