与在*路径操作函数*中使用 `Query`、`Path` 、`Body` 声明校验与元数据的方式一样，可以使用 Pydantic 的 `Field` 在 Pydantic 模型内部声明校验和元数据。

## 导入 `Field` { #import-field }

首先，从 Pydantic 中导入 `Field`：

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[4] *}

/// warning | 警告

注意，与从 `fastapi` 导入 `Query`，`Path`、`Body` 不同，要直接从 `pydantic` 导入 `Field` 。

///

## 声明模型属性 { #declare-model-attributes }

然后，使用 `Field` 定义模型的属性：

				if name == "" {
					subName := field.Name
					const key = "COMPOSITE"
					if composite, found := settings[key]; found {
						if len(composite) == 0 || composite == key {
							err = fmt.Errorf(
								"the composite tag of %s.%s cannot be empty",
								field.Schema.Name,
								field.Name)
							return
						}
						subName = composite
					}
					name = field.Schema.namer.IndexName(

        }
    }

    // Helper method to set private dialectIndex field using reflection
    private void setDialectIndex(SmbComNegotiateResponse response, int dialectIndex) {
        try {
            Field field = response.getClass().getDeclaredField("dialectIndex");
            field.setAccessible(true);
            field.set(response, dialectIndex);
        } catch (Exception e) {

                Field[] fields = FIELDS_BY_CLASS.computeIfAbsent(cls, k -> cls.getDeclaredFields());

                for (Field field : fields) {
                    Class<?> type = field.getType();
                    if (isQualifiedForInterpolation(field, type)) {
                        boolean isAccessible = field.isAccessible();
                        field.setAccessible(true);
                        try {

func (z *BatchJobKV) DecodeMsg(dc *msgp.Reader) (err error) {
	var field []byte
	_ = field
	var zb0001 uint32
	zb0001, err = dc.ReadMapHeader()
	if err != nil {
		err = msgp.WrapError(err)
		return
	}
	for zb0001 > 0 {
		zb0001--
		field, err = dc.ReadMapKeyPtr()
		if err != nil {
			err = msgp.WrapError(err)
			return
		}
		switch msgp.UnsafeString(field) {
		case "Key":
			z.Key, err = dc.ReadString()

## 匯入 `Field` { #import-field }

首先，你需要匯入它：

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[4] *}


/// warning

請注意，`Field` 是直接從 `pydantic` 匯入的，不像其他（如 `Query`、`Path`、`Body` 等）是從 `fastapi` 匯入。

///

## 宣告模型屬性 { #declare-model-attributes }

接著你可以在模型屬性上使用 `Field`：

            assert (
                is_scalar_field(field)
                or field_annotation_is_scalar_sequence(field.field_info.annotation)
                or lenient_issubclass(field.field_info.annotation, BaseModel)
            ), f"Query parameter {param_name!r} must be one of the supported types"

    return ParamDetails(type_annotation=type_annotation, depends=depends, field=field)

func (z *allTierStats) DecodeMsg(dc *msgp.Reader) (err error) {
	var field []byte
	_ = field
	var zb0001 uint32
	zb0001, err = dc.ReadMapHeader()
	if err != nil {
		err = msgp.WrapError(err)
		return
	}
	for zb0001 > 0 {
		zb0001--
		field, err = dc.ReadMapKeyPtr()
		if err != nil {
			err = msgp.WrapError(err)
			return
		}
		switch msgp.UnsafeString(field) {
		case "ts":
			var zb0002 uint32

        /**
         * Splits a field name into its components.
         *
         * @param defaultField the default field name
         * @param field the field name to split
         * @return a Pair containing the field name and extension key
         */
        protected Pair<String, String> splitField(final String defaultField, final String field) {
            final int indexOf = field.indexOf(':');
            if (indexOf < 0) {

    }

    @Test
    public void test_complex_field_names() {
        // Test various complex field names
        String[] fieldNames = { "simple_field", "field-with-dashes", "field.with.dots", "field_with_underscores", "fieldWithCamelCase",
                "field with spaces", "field@with#special!chars", "フィールド名", "字段名称", "필드명" };

        for (String fieldName : fieldNames) {