# 请求体 - 嵌套模型 { #body-nested-models }

使用 **FastAPI**，你可以定义、校验、记录文档并使用任意深度嵌套的模型（归功于Pydantic）。

## List 字段 { #list-fields }

你可以将一个属性定义为一个子类型。例如，Python `list`：

{* ../../docs_src/body_nested_models/tutorial001_py310.py hl[12] *}

这将使 `tags` 成为一个由元素组成的列表。不过它没有声明每个元素的类型。

## 带类型参数的 List 字段 { #list-fields-with-type-parameter }

不过，Python 有一种用于声明具有内部类型（类型参数）的列表的特定方式：

### 声明带类型参数的 `list` { #declare-a-list-with-a-type-parameter }

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class AbstractListTester<E extends @Nullable Object> extends AbstractCollectionTester<E> {
  /*
   * Previously we had a field named list that was initialized to the value of
   * collection in setUp(), but that caused problems when a tester changed the
   * value of list or collection but not both.
   */
  protected final List<E> getList() {

        NegTokenTarg nt = new NegTokenTarg();
        assertEquals(NegTokenTarg.UNSPECIFIED_RESULT, nt.getResult(), "new object should have UNSPECIFIED_RESULT");
    }

    @Test
    @DisplayName("serialization omits tags when field is null")
    void testSerializationOmittingNullFields() throws IOException {
        NegTokenTarg token = new NegTokenTarg();
        token.setResult(NegTokenTarg.ACCEPT_INCOMPLETE);

                                    </la:info>
                                    <la:errors/>
                                </div>
                                    <%-- Form Fields --%>
                                <table class="table table-bordered" aria-label="<la:message key="labels.bad_word_details" />">
                                    <tbody>
                                    <tr>

            this.parsed = true;
        }

        boolean isParsed() {
            return parsed;
        }
    }

    @Test
    @DisplayName("Default state is null for both fields")
    void defaultStateIsNull() {
        TestSpnegoToken t = new TestSpnegoToken();
        assertNull(t.getMechanismToken(), "mechanismToken should default to null");

                                    </la:info>
                                    <la:errors/>
                                </div>
                                    <%-- Form Fields --%>
                                <table class="table table-bordered" aria-label="<la:message key="labels.file_auth_details" />">
                                    <tbody>
                                    <tr>

                                    </la:info>
                                    <la:errors/>
                                </div>
                                    <%-- Form Fields --%>
                                <table class="table table-bordered" aria-label="<la:message key="labels.labeltype_details" />">
                                    <tbody>
                                    <tr>

///

## Sobre "Campos de formulário" { #about-form-fields }

A forma como os formulários HTML (`<form></form>`) enviam os dados para o servidor normalmente usa uma codificação "especial" para esses dados, é diferente do JSON.

///

## À propos des « champs de formulaire » { #about-form-fields }

La manière dont les formulaires HTML (`<form></form>`) envoient les données au serveur utilise normalement un encodage « spécial » pour ces données, différent de JSON.

 * under the License.
 */
package org.apache.maven.internal.impl;

import javax.inject.Named;
import javax.inject.Provider;

import java.lang.annotation.Annotation;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;