运行示例并访问 <a href="http://127.0.0.1:8000/items/3" class="external-link" target="_blank">http://127.0.0.1:8000/items/3</a>，返回的响应如下：

```JSON
{"item_id":3}
```

/// check | 检查

注意，函数接收并返回的值是 `3`（ `int`），不是 `"3"`（`str`）。

**FastAPI** 通过类型声明自动<abbr title="将来自 HTTP 请求中的字符串转换为 Python 数据类型">**解析**请求中的数据</abbr>。

///

## 数据校验

Por causa disso, o próprio **FastAPI** fornece uma documentação alternativa da API (usando ReDoc), que você pode acessar em <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>:

    }

    @Override
    protected Class<? extends FileConfig> typeOfSelectedEntity() {
        return FileConfig.class;
    }

    @Override
    protected Class<FileConfig> typeOfHandlingEntity() {
        return FileConfig.class;
    }

    @Override
    protected Class<FileConfigCB> typeOfHandlingConditionBean() {
        return FileConfigCB.class;
    }

    }

    @Override
    protected Class<? extends SearchLog> typeOfSelectedEntity() {
        return SearchLog.class;
    }

    @Override
    protected Class<SearchLog> typeOfHandlingEntity() {
        return SearchLog.class;
    }

    @Override
    protected Class<SearchLogCB> typeOfHandlingConditionBean() {
        return SearchLogCB.class;
    }

    ImmutableList.Builder<String> builder = ImmutableList.builder();
    assertThrows(NullPointerException.class, () -> builder.add((String) null));

    assertThrows(NullPointerException.class, () -> builder.add((String[]) null));

    assertThrows(NullPointerException.class, () -> builder.add("a", null, "b"));
  }

  public void testBuilderAddAllHandlesNullsCorrectly() {
    {

   * described in the class documentation.
   *
   * @throws NullPointerException if any of {@code elements} is null
   * @since 6.0
   */
  public static <E> ImmutableMultiset<E> copyOf(E[] elements) {
    return copyFromElements(elements);
  }

  /**
   * Returns an immutable multiset containing the given elements, in the "grouped iteration order"
   * described in the class documentation.
   *

        val alpnClass = Class.forName(alpnClassName, true, null)
        val providerClass = Class.forName("$alpnClassName\$Provider", true, null)
        val clientProviderClass = Class.forName("$alpnClassName\$ClientProvider", true, null)
        val serverProviderClass = Class.forName("$alpnClassName\$ServerProvider", true, null)
        val putMethod = alpnClass.getMethod("put", SSLSocket::class.java, providerClass)

import org.codelibs.core.exception.InvocationTargetRuntimeException;

/**
 * Utility class for {@link Constructor} operations.
 *
 * @author higa
 */
public abstract class ConstructorUtil {

    /**
     * Do not instantiate.
     */
    protected ConstructorUtil() {
    }

    /**
     * Creates and initializes a new instance of the class declared by the specified constructor with the given initialization parameters.
     *

    }
  }

  private class ProgressRequestBody(
    private val delegate: RequestBody,
    private val progressListener: ProgressListener,
  ) : RequestBody() {
    override fun contentType() = delegate.contentType()

    @Throws(IOException::class)
    override fun contentLength(): Long = delegate.contentLength()

    @Throws(IOException::class)
    override fun writeTo(sink: BufferedSink) {

from fastapi.responses import JSONResponse
from fastapi.testclient import TestClient
from pydantic import BaseModel

app = FastAPI()


class JsonApiResponse(JSONResponse):
    media_type = "application/vnd.api+json"


class Error(BaseModel):
    status: str
    title: str


class JsonApiError(BaseModel):
    errors: list[Error]


@app.get(
    "/a/{id}",
    response_class=JsonApiResponse,