Bedenken Sie, dass Datenklassen nicht alles können, was Pydantic-Modelle können.

Daher müssen Sie möglicherweise weiterhin Pydantic-Modelle verwenden.

Wenn Sie jedoch eine Menge Datenklassen herumliegen haben, ist dies ein guter Trick, um sie für eine Web-API mithilfe von FastAPI zu verwenden. 🤓

///

## Datenklassen in `response_model` { #dataclasses-in-response-model }

Sie können `dataclasses` auch im Parameter `response_model` verwenden:

/// info

Keep in mind that dataclasses can't do everything Pydantic models can do.

So, you might still need to use Pydantic models.

But if you have a bunch of dataclasses laying around, this is a nice trick to use them to power a web API using FastAPI. 🤓

///

## Dataclasses in `response_model` { #dataclasses-in-response-model }

You can also use `dataclasses` in the `response_model` parameter:

También obtendrás autocompletado para el payload a enviar:

<img src="/img/tutorial/generate-clients/image03.png">

/// tip | Consejo

Nota el autocompletado para `name` y `price`, que fue definido en la aplicación de FastAPI, en el modelo `Item`.

///

Tendrás errores en línea para los datos que envíes:

<img src="/img/tutorial/generate-clients/image04.png">

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...`description`과 `tax`는 (기본 값이 `None`으로 되어 있어) 선택적이기 때문에, 이 JSON "`object`"는 다음과 같은 상황에서도 유효합니다:

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## 매개변수로서 선언하기 { #declare-it-as-a-parameter }

            .createTestSuite());
    return suite;
  }

  @GwtIncompatible // SerializableTester
  public void testViewSerialization() {
    Map<String, Integer> map = ImmutableSortedMap.of("one", 1, "two", 2, "three", 3);
    SerializableTester.reserializeAndAssert(map.entrySet());
    SerializableTester.reserializeAndAssert(map.keySet());
    assertEquals(
        new ArrayList<>(map.values()),

import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertTrue;

/**
 * Verifies scope inheritance of direct and transitive dependencies.
 *
 * Should show three behaviors:
 *
 * 1. dependencyManagement should override the scope of transitive dependencies.
 * 2. Direct dependencies should override the scope of dependencyManagement.

    List<Double> one = Arrays.asList(1.0);
    assertThat(Doubles.toArray(one)).isEqualTo(ARRAY1);

    double[] array = {0.0, 1.0, Math.PI};

    List<Double> three = Arrays.asList(0.0, 1.0, Math.PI);
    assertThat(Doubles.toArray(three)).isEqualTo(array);

    assertThat(Doubles.toArray(Doubles.asList(array))).isEqualTo(array);
  }

  public void testToArray_threadSafe() {

```Python hl_lines="2  7-10 23-25"
from fastapi import FastAPI
from pydantic import BaseModel

app = FastAPI()


class Item(BaseModel):
    name: str
    price: float
    is_offer: bool | None = None


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: str | None = None):

As features progress through the lifecycle of early prototype, incubation, and stabilization, their corresponding properties may also be updated.

Examples as of Gradle 9.3.0:

* `org.gradle.internal.operations.trace` – internal property
* `org.gradle.configuration-cache` – public property of a stable feature
* `org.gradle.configuration-cache.parallel` – public property of an unstable feature

        assertTrue(exception instanceof Exception);
        assertTrue(exception instanceof Throwable);
    }

    @Test
    public void test_stackTraceWithCause() {
        // Test that stack trace is properly preserved with cause
        String innerMessage = "Inner exception";
        String outerMessage = "Outer exception";
        RuntimeException innerException = new RuntimeException(innerMessage);