# Hướng dẫn sử dụng

Hướng dẫn này cho bạn thấy từng bước cách sử dụng **FastAPI** đa số các tính năng của nó.

Mỗi phần được xây dựng từ những phần trước đó, nhưng nó được cấu trúc thành các chủ đề riêng biệt, do đó bạn có thể xem trực tiếp từng phần cụ thể bất kì để giải quyết những API cụ thể mà bạn cần.

Nó cũng được xây dựng để làm việc như một tham chiếu trong tương lai.

Do đó bạn có thể quay lại và tìm chính xác những gì bạn cần.

## Chạy mã

import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)
@TypeQualifierDefault({FIELD, METHOD, PARAMETER})
@Nonnull

import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)
@TypeQualifierDefault({FIELD, METHOD, PARAMETER})
@Nonnull

import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)
@TypeQualifierDefault({FIELD, METHOD, PARAMETER})
@Nonnull

import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)
@TypeQualifierDefault({FIELD, METHOD, PARAMETER})
@Nonnull

import javax.annotation.Nonnull;
import javax.annotation.meta.TypeQualifierDefault;

/**
 * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
 * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
 * "undo" it as best we can.
 */
@GwtCompatible
@Retention(RUNTIME)
@Target(TYPE)
@TypeQualifierDefault({FIELD, METHOD, PARAMETER})
@Nonnull

/**
 * Interface that defines some kind of enums that can be extended by Maven plugins or extensions.
 *
 * Implementation must have {@code equals()} and {@code hashCode()} implemented, so implementations of this interface
 * can be used as keys.
 *
 * @since 4.0.0
 */
@Experimental
public interface ExtensibleEnum {

    /**

        ClassMetaData classMetaData = classDoc.getClassMetaData();
        String superClassName = classMetaData.getSuperClassName();
        if (superClassName != null) {
            // Assume this is a class and so has implemented all properties and methods somewhere in the superclass hierarchy
            ClassDoc superClass = model.getClassDoc(superClassName);
            classDoc.setSuperClass(superClass);

    entry = cacheEntry1;
    if (entry != null && entry.key == key) {
      return entry.value;
    }
    entry = cacheEntry2;
    if (entry != null && entry.key == key) {
      // Promote second cache entry to first so the access pattern
      // [K1, K2, K1, K3, K1, K4...] still hits the cache half the time.
      addToCache(entry);
      return entry.value;
    }
    return null;
  }

  @Override
  void clearCache() {

              annotationClass, propertyName, annotationClass.getDeclaringClass()),
          annotationClass.getDeclaringClass(),
          returnType.getComponentType());
    }
  }

  // This is public so that tests for Feature enums we haven't yet imagined
  // can reuse it.
  public static <E extends Enum<?> & Feature<?>> void assertGoodFeatureEnum(
      Class<E> featureEnumClass) {