```

////


/// info

想进一步了解 <a href="https://docs.pydantic.dev/" class="external-link" target="_blank">Pydantic，请阅读其文档</a>.

///

整个 **FastAPI** 建立在 Pydantic 的基础之上。

实际上你将在 [教程 - 用户指南](tutorial/index.md){.internal-link target=_blank} 看到很多这种情况。

## **FastAPI** 中的类型提示

**FastAPI** 利用这些类型提示来做下面几件事。

使用 **FastAPI** 时用类型提示声明参数可以获得：

* **编辑器支持**。

/**
 * Adapter to convert an {@link Enumeration} to an {@link Iterator}.
 *
 * @author shot
 * @param <T> the element type
 */
public class EnumerationIterator<T> implements Iterator<T> {

    private Enumeration<T> enumeration = null;

    /**
     * Returns an {@link Iterable} that wraps an {@link Enumeration} for use in a for-each statement.
     *

import org.xml.sax.helpers.DefaultHandler;

/**
 * Utility class for {@link SAXParser}.
 *
 * @author higa
 */
public abstract class SAXParserUtil {

    /**
     * Do not instantiate.
     */
    protected SAXParserUtil() {
    }

    /**
     * Parses the content of the specified {@link InputSource} as XML using the specified {@link DefaultHandler}.
     *
     * @param parser

        }
    }

    /**
     * Returns the value of a {@literal static} {@link Field} as a {@link String}.
     *
     * @param field the field (must not be {@literal null})
     * @return the field value
     * @throws IllegalAccessRuntimeException {@link IllegalAccessException} if an error occurs
     * @see #getString(Field, Object)
     */

 * <li>{@link #loadIndexSettings()}: Loads the index settings from a JSON file.</li>
 * </ul>
 *
 * <p>Fields:
 * <ul>
 * <li>{@link #logger}: Logger instance for logging debug information.</li>
 * <li>{@link #client}: OpenSearch client instance.</li>
 * <li>{@link #arraySettingsIndexName}: Name of the array settings index.</li>
 * <li>{@link #settingsId}: ID of the settings.</li>

.main-header .nav-link > .svg-inline--fa,\n.text-sm .main-header .nav-link > .ion, .main-header.text-sm .nav-link > .fa,\n.main-header.text-sm .nav-link > .fas,\n.main-header.text-sm .nav-link > .far,\n.main-header.text-sm .nav-link > .fab,\n.main-header.text-sm .nav-link > .fal,\n.main-header.text-sm .nav-link > .fad,\n.main-header.text-sm .nav-link > .svg-inline--fa,\n.main-header.text-sm .nav-link > .ion {\n  font-size: 0.875rem;\n}\n\n.main-header .navbar-nav .nav-item {\n  margin: 0;\n}\n\n.main-header...

    }

    /**
     * Creates a new instance of {@link SAXParser} using the default configuration of {@link SAXParserFactory}.
     *
     * @return A new instance of {@link SAXParser}.
     */
    public static SAXParser newSAXParser() {
        return newSAXParser(newInstance());
    }

    /**
     * Creates a new instance of {@link SAXParser} using the specified {@link SAXParserFactory}.
     *
     * @param factory

import org.codelibs.core.net.URLUtil;

/**
 * Utility class for {@link Properties} operations.
 *
 * @author higa
 */
public abstract class PropertiesUtil {

    /**
     * Do not instantiate.
     */
    protected PropertiesUtil() {
    }

    /**
     * Wraps exception handling for {@link Properties#load(InputStream)}.
     * <p>
     * The input stream is not closed.
     * </p>

import java.util.List;
import java.util.stream.DoubleStream;
import org.jspecify.annotations.NullUnmarked;

/**
 * Inputs, expected outputs, and helper methods for tests of {@link StatsAccumulator}, {@link
 * Stats}, {@link PairedStatsAccumulator}, and {@link PairedStats}.
 *
 * @author Pete Gillin
 */
@NullUnmarked
class StatsTesting {
  // TODO(cpovirk): Convince myself that this larger error makes sense.

    }

    /**
     * A link from a phase to another phase, consisting of a type which can be
     * {@link Kind#BEFORE} or {@link Kind#AFTER}, and a {@link Pointer} to
     * another phase.
     */
    interface Link {
        enum Kind {
            BEFORE,
            AFTER
        }

        /**
         * Returns the kind of link (BEFORE or AFTER).
         *