Da wir eine relative URL verwenden, würde sich das, wenn sich Ihre API unter `https://example.com/` befindet, auf `https://example.com/token` beziehen. Wenn sich Ihre API jedoch unter `https://example.com/api/v1/` befände, würde es sich auf `https://example.com/api/v1/token` beziehen.

/// tip | 提示

在此，`tokenUrl="token"` 指向的是暂未创建的相对 URL `token`。这个相对 URL 相当于 `./token`。

因为使用的是相对 URL，如果 API 位于 `https://example.com/`，则指向 `https://example.com/token`。但如果 API 位于 `https://example.com/api/v1/`，它指向的就是`https://example.com/api/v1/token`。

使用相对 URL 非常重要，可以确保应用在遇到[使用代理](../../advanced/behind-a-proxy.md){.internal-link target=_blank}这样的高级用例时，也能正常运行。

///

    description: Union[str, None] = None
    price: float
    tax: Union[float, None] = None


@app.put("/items/{item_id}")
async def update_item(
    item_id: int,
    item: Item = Body(
        examples=[
            {
                "name": "Foo",
                "description": "A very nice Item",
                "price": 35.4,
                "tax": 3.2,
            }
        ],
    ),
):

    `APIRouter` class, used to group *path operations*, for example to structure
    an app in multiple files. It would then be included in the `FastAPI` app, or
    in another `APIRouter` (ultimately included in the app).

    Read more about it in the
    [FastAPI docs for Bigger Applications - Multiple Files](https://fastapi.tiangolo.com/tutorial/bigger-applications/).

    ## Example

    ```python

 * with {@link #where} and types are resolved using {@link #resolveType}.
 *
 * <p>Note that usually type mappings are already implied by the static type hierarchy (for example,
 * the {@code E} type variable declared by class {@code List} naturally maps to {@code String} in
 * the context of {@code class MyStringList implements List<String>}). In such case, prefer to use

policy grants access to buckets with name starting with example. ## In addition, grants objects read permissions on buckets starting with example. # - name: readonlyexamplepolic # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:GetObject" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:GetBucketLocation" # - "s3:ListBucket" # - "s3:ListBucketMultipartU" ## conditionsexample policy creates all access to example bucket with aws:username="johndoe" and source ip range...

policy grants access to buckets with name starting with example. ## In addition, grants objects read permissions on buckets starting with example. # - name: readonlyexamplepolic # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:GetObject" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:GetBucketLocation" # - "s3:ListBucket" # - "s3:ListBucketMultipartU" ## conditionsexample policy creates all access to example bucket with aws:username="johndoe" and source ip range...

policy grants access to buckets with name starting with example. ## In addition, grants objects read permissions on buckets starting with example. # - name: readonlyexamplepolic # statements: # - resources: # - 'arn:aws:s3:::example*/*' # actions: # - "s3:GetObject" # - resources: # - 'arn:aws:s3:::example*' # actions: # - "s3:GetBucketLocation" # - "s3:ListBucket" # - "s3:ListBucketMultipartU" ## conditionsexample policy creates all access to example bucket with aws:username="johndoe" and source ip range...

 * encoding for URL decoding.</p>
 *
 * <p>Example usage:</p>
 * <pre>
 * {@code
 * IdnDnsResolver resolver = new IdnDnsResolver();
 * resolver.setFlag(IDN.ALLOW_UNASSIGNED);
 * resolver.setEncoding("UTF-8");
 * InetAddress[] addresses = resolver.resolve("example.com");
 * }
 * </pre>
 *
 */
public class IdnDnsResolver implements DnsResolver {

    result = 31 * result + socketAddress.hashCode()
    return result
  }

  /**
   * Returns a string with the URL hostname, socket IP address, and socket port, like one of these:
   *
   *  * `example.com:80 at 1.2.3.4:8888`
   *  * `example.com:443 via proxy [::1]:8888`
   *
   * This omits duplicate information when possible.
   */
  override fun toString(): String =
    buildString {