1. Nous continuons à importer `field` depuis les `dataclasses` standard.

2. `pydantic.dataclasses` est un remplacement drop‑in pour `dataclasses`.

3. La dataclass `Author` inclut une liste de dataclasses `Item`.

4. La dataclass `Author` est utilisée comme paramètre `response_model`.

# 使用数据类 { #using-dataclasses }

FastAPI 基于 **Pydantic** 构建，我已经向你展示过如何使用 Pydantic 模型声明请求与响应。

但 FastAPI 也支持以相同方式使用 [`dataclasses`](https://docs.python.org/3/library/dataclasses.html)：

{* ../../docs_src/dataclasses_/tutorial001_py310.py hl[1,6:11,18:19] *}

这仍然得益于 **Pydantic**，因为它对 [`dataclasses` 的内置支持](https://docs.pydantic.dev/latest/concepts/dataclasses/#use-of-stdlib-dataclasses-with-basemodel)。

from dataclasses import dataclass, field

from fastapi import FastAPI


@dataclass
class Item:
    name: str
    price: float
    tags: list[str] = field(default_factory=list)
    description: str | None = None
    tax: float | None = None


app = FastAPI()


@app.get("/items/next", response_model=Item)
async def read_next_item():
    return {
        "name": "Island In The Moon",
        "price": 12.99,

from dataclasses import field  # (1)

from fastapi import FastAPI
from pydantic.dataclasses import dataclass  # (2)


@dataclass
class Item:
    name: str
    description: str | None = None


@dataclass
class Author:
    name: str
    items: list[Item] = field(default_factory=list)  # (3)


app = FastAPI()


@app.post("/authors/{author_id}/items/", response_model=Author)  # (4)

from dataclasses import dataclass

from fastapi import FastAPI


@dataclass
class Item:
    name: str
    price: float
    description: str | None = None
    tax: float | None = None


app = FastAPI()


@app.post("/items/")
async def create_item(item: Item):

from __future__ import annotations

import uuid
from dataclasses import dataclass, field

from dirty_equals import IsUUID
from fastapi import FastAPI
from fastapi.testclient import TestClient
from inline_snapshot import snapshot


@dataclass
class Item:
    id: uuid.UUID
    name: str
    price: float
    tags: list[str] = field(default_factory=list)
    description: str | None = None
    tax: float | None = None

If a class is needed, instead create a regular function dependency that returns a class instance.

Do this:

```python
from dataclasses import dataclass
from typing import Annotated

from fastapi import Depends, FastAPI

app = FastAPI()


@dataclass
class DatabasePaginator:
    offset: int = 0
    limit: int = 100
    q: str | None = None

    def get_page(self) -> dict:

import inspect
import sys
from collections.abc import Callable
from dataclasses import dataclass, field
from functools import cached_property, partial
from typing import Any, Literal

from fastapi._compat import ModelField
from fastapi.security.base import SecurityBase
from fastapi.types import DependencyCacheKey

if sys.version_info >= (3, 13):  # pragma: no cover
    from inspect import iscoroutinefunction
else:  # pragma: no cover

            exclude_none=exclude_none,
            exclude_defaults=exclude_defaults,
            sqlalchemy_safe=sqlalchemy_safe,
        )
    if dataclasses.is_dataclass(obj):
        assert not isinstance(obj, type)
        obj_dict = dataclasses.asdict(obj)
        return jsonable_encoder(
            obj_dict,
            include=include,
            exclude=exclude,
            by_alias=by_alias,

import types
import typing
import warnings
from collections import deque
from collections.abc import Mapping, Sequence
from dataclasses import is_dataclass
from typing import (
    Annotated,
    Any,
    TypeGuard,
    TypeVar,
    Union,
    get_args,
    get_origin,
)

from fastapi.types import UnionType
from pydantic import BaseModel
from pydantic.version import VERSION as PYDANTIC_VERSION