}
    }

    /**
     * Test that password comparison is constant-time by comparing execution times
     * for passwords that differ at different positions.
     */
    @Test
    public void testConstantTimePasswordComparison() throws Exception {
        char[] basePassword = "supersecretpassword123456789".toCharArray();
        char[] diffAtStart = "Xupersecretpassword123456789".toCharArray();

  }

  static void checkExactMatches(CharMatcher m, char[] chars) {
    Set<Character> positive = Sets.newHashSetWithExpectedSize(chars.length);
    for (char c : chars) {
      positive.add(c);
    }
    for (int c = 0; c <= Character.MAX_VALUE; c++) {
      assertFalse(positive.contains(Character.valueOf((char) c)) ^ m.matches((char) c));
    }
  }

  static char[] randomChars(Random rand, int size) {

### Nâng cấp tài liệu API thay thế

Và bây giờ truy cập tới <a href="http://127.0.0.1:8000/redoc" class="external-link" target="_blank">http://127.0.0.1:8000/redoc</a>.

* Tài liệu thay thế cũng sẽ phản ánh tham số và body mới:

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Tóm lại

Bạn khai báo **một lần** kiểu dữ liệu của các tham số, body, etc là các tham số của hàm số.

      "The hash code of a char is the int version of the char itself, so it's simplest to return"
          + " that.")
  public static int hashCode(char value) {
    return value;
  }

  /**
   * Returns the {@code char} value that is equal to {@code value}, if possible.
   *
   * @param value any value in the range of the {@code char} type
   * @return the {@code char} value that equals {@code value}

      "The hash code of a char is the int version of the char itself, so it's simplest to return"
          + " that.")
  public static int hashCode(char value) {
    return value;
  }

  /**
   * Returns the {@code char} value that is equal to {@code value}, if possible.
   *
   * @param value any value in the range of the {@code char} type
   * @return the {@code char} value that equals {@code value}

   * nullness checker can already "prove" are non-null. That means that the first parameter to
   * checkNotNull *should* be annotated to require it to be non-null.
   *
   * However, for a variety of reasons, Google developers have written a ton of code over the past
   * decade that assumes that they can use checkNotNull for non-precondition checks. I had hoped to

  }

  private static CharMatcher.IsEither isEither(char c1, char c2) {
    return new CharMatcher.IsEither(c1, c2);
  }

  /** Implementation of {@link #anyOf(CharSequence)} for exactly two characters. */
  private static final class IsEither extends FastMatcher {

    private final char match1;
    private final char match2;

    IsEither(char match1, char match2) {
      this.match1 = match1;

     */
    public static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

    /**
     * This is an alternative to the <code>java.lang.Integer.toHexString</code>
     * method. It is an efficient relative that also will pad the left side so
     * that the result is <code>size</code> digits.
     *

    /**
     * Performs constant-time comparison of two char arrays to prevent timing attacks.
     * This method always compares the full length of both arrays, regardless of when
     * differences are found, making the execution time independent of the position
     * of differing characters.
     *
     * @param a first char array to compare
     * @param b second char array to compare
     * @return true if arrays are equal, false otherwise

    // than wrapping cbuf in a light-weight CharSequence.
    target.append(new String(cbuf, off, len));
  }

  /*
   * Override a few functions for performance reasons to avoid creating unnecessary strings.
   */

  @Override
  public void write(int c) throws IOException {
    checkNotClosed();
    target.append((char) c);
  }

  @Override