## 声明模型属性

然后，使用 `Field` 定义模型的属性：

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[11:14] *}

`Field` 的工作方式和 `Query`、`Path`、`Body` 相同，参数也相同。

/// note | 技术细节

实际上，`Query`、`Path` 都是 `Params` 的子类，而 `Params` 类又是 Pydantic 中 `FieldInfo` 的子类。

Pydantic 的 `Field` 返回也是 `FieldInfo` 的类实例。

`Body` 直接返回的也是 `FieldInfo` 的子类的对象。后文还会介绍一些 `Body` 的子类。

注意，从 `fastapi` 导入的 `Query`、`Path` 等对象实际上都是返回特殊类的函数。

///

 */
abstract class AbstractBuildScanInfoCollectingService : BuildService<AbstractBuildScanInfoCollectingService.Params>, OperationCompletionListener {
    /**
     * To be compatible with configuration cache, this field must be Serializable.
     */
    abstract val collectedInformation: Serializable

    interface Params : BuildServiceParameters {
        val monitoredTaskPaths: SetProperty<String>
    }

import me.champeau.gradle.japicmp.report.Violation

class IncubatingInternalInterfaceAddedRule extends AbstractSuperClassChangesRule {

    IncubatingInternalInterfaceAddedRule(Map<String, Object> params) {
        super(params)
    }

    protected boolean changed(JApiCompatibility member) {
        return member.getChangeStatus() == JApiChangeStatus.MODIFIED
    }

            <template>writer-stax.vm</template>
          </templates>
          <params>
            <param>packageModelV4=org.apache.maven.api.cli.extensions</param>
            <param>packageToolV4=org.apache.maven.cling.internal.extension.io</param>
            <param>locationTracking=true</param>
          </params>
          <velocityBasedir>${project.basedir}/../../src/mdo</velocityBasedir>
        </configuration>

      Parameter param = params.get(i);
      if (i != indexOfParamToSetToNull) {
        args[i] = getDefaultValue(param.getType());
        Assert.assertTrue(
            "Can't find or create a sample instance for type '"
                + param.getType()
                + "'; please provide one using NullPointerTester.setDefault()",
            args[i] != null || isNullable(param));
      }
    }

        return parameters;
    }

    private static void decomposeParameterIntoUserInstructions(
            MojoDescriptor mojo, Parameter param, StringBuilder messageBuffer) {
        String expression = param.getExpression();

        if (param.isEditable()) {
            boolean isArray = param.getType().endsWith("[]");
            boolean isCollection = false;
            boolean isMap = false;
            boolean isProperties = false;

@app.get("/int/{param:int}")
def int_convertor(param: int = Path()):
    return {"int": param}


@app.get("/float/{param:float}")
def float_convertor(param: float = Path()):
    return {"float": param}


@app.get("/path/{param:path}")
def path_convertor(param: str = Path()):
    return {"path": param}


@app.get("/query/")
def query_convertor(param: str = Query()):
    return {"query": param}

from enum import Enum, IntEnum
from typing import (
    Annotated,
    Any,
    Callable,
    Optional,
    Union,
)

from annotated_doc import Doc
from fastapi import params
from fastapi._compat import (
    ModelField,
    Undefined,
    annotation_is_pydantic_v1,
    lenient_issubclass,
)
from fastapi.datastructures import Default, DefaultPlaceholder

import java.util.concurrent.ConcurrentHashMap
import javax.inject.Inject


private
val logger = LoggerFactory.getLogger("daemonTracker")


abstract class DaemonTracker : BuildService<DaemonTracker.Params>, AutoCloseable {
    interface Params : BuildServiceParameters {
        val rootProjectDir: DirectoryProperty
    }

    @get:Inject
    abstract val execOperations: ExecOperations

    private

import pytest
from fastapi.testclient import TestClient


@pytest.fixture(
    name="client",
    params=[
        pytest.param("tutorial008e_py39"),
        pytest.param("tutorial008e_an_py39"),
    ],
)
def get_client(request: pytest.FixtureRequest):
    mod = importlib.import_module(f"docs_src.dependencies.{request.param}")

    client = TestClient(mod.app)
    return client


def test_get_users_me(client: TestClient):