}
            saveInfo(messages -> messages.addSuccessUploadMappingFile(GLOBAL));
            return redirectWith(getClass(), moreUrl("list/1").params("dictId", form.dictId));
        }).orElseGet(() -> {
            throwValidationError(messages -> messages.addErrorsFailedToUploadMappingFile(GLOBAL), () -> uploadpage(form.dictId));
            return null;
        });

    TF_Operation* less_than = LessThan(
        params->cond_inputs[0], params->cond_inputs[1], params->cond_graph, s_);
    ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);
    params->cond_output = {less_than, 0};

    TF_Operation* add1 = Add(params->body_inputs[0], params->body_inputs[1],
                             params->body_graph, s_, "add1");
    ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);

    data = response.json()
    assert response.status_code == 200
    assert data == {"name": "invalid", "price": 3.2, "owner_ids": None}


def test_valid_none_none():
    response = client.get("/items/validnone", params={"send_none": "true"})
    data = response.json()
    assert response.status_code == 200
    assert data is None


def test_double_invalid():
    with pytest.raises(ResponseValidationError):

     *
     * @see org.codelibs.fess.crawler.extractor.Extractor#getText(java.io.InputStream,
     * java.util.Map)
     */
    @Override
    public ExtractData getText(final InputStream in, final Map<String, String> params) {
        if (in == null) {
            throw new CrawlerSystemException("The inputstream is null.");
        }
        try {
            @SuppressWarnings("resource")

            throw new IORuntimeException(e);
        }
    }

    protected HttpEntity parseRequestParameters(final String params, final List<Pair<String, String>> paramList, final String encoding) {
        try {
            final List<BasicNameValuePair> parameters =
                    StreamUtil.split(params, "&").get(stream -> stream.filter(StringUtil::isNotBlank).map(s -> {
                        final String name;

        Object proxy, Method method, @Nullable Object[] args) {
      Invokable<?, ?> invokable = interfaceType.method(method);
      ImmutableList<Parameter> params = invokable.getParameters();
      for (int i = 0; i < args.length; i++) {
        Parameter param = params.get(i);
        if (!isNullable(param)) {
          checkNotNull(args[i]);
        }
      }

///

```Python hl_lines="11-14"
{!> ../../docs_src/body_fields/tutorial001.py!}
```

////

`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。

///

from typing import Optional

from fastapi import FastAPI
from fastapi.params import Param
from fastapi.testclient import TestClient

app = FastAPI()


@app.get("/items/")
def read_items(q: Optional[str] = Param(default=None)):  # type: ignore
    return {"q": q}


client = TestClient(app)


def test_default_param_query_none():
    response = client.get("/items/")
    assert response.status_code == 200, response.text

     * @see
     * org.codelibs.fess.crawler.extractor.impl.Extractor#getText(java.io.InputStream,
     * java.util.Map)
     */
    @Override
    public ExtractData getText(final InputStream in, final Map<String, String> params) {
        if (in == null) {
            throw new CrawlerSystemException("The inputstream is null.");
        }
        try {
            @SuppressWarnings("resource")

            }
            saveInfo(messages -> messages.addSuccessUploadKuromojiFile(GLOBAL));
            return redirectWith(getClass(), moreUrl("list/1").params("dictId", form.dictId));
        }).orElseGet(() -> {
            throwValidationError(messages -> messages.addErrorsFailedToUploadKuromojiFile(GLOBAL), () -> uploadpage(form.dictId));
            return null;
        });