public FtpClient() {
        // Default constructor
    }

    /** Character encoding for FTP operations */
    protected String charset = Constants.UTF_8;

    /** Helper for managing content length limits */
    @Resource
    protected ContentLengthHelper contentLengthHelper;

    /**
     * The FTP authentication holder.
     */
    protected volatile FtpAuthenticationHolder ftpAuthenticationHolder;

        }

        if (skipped < offset) {
          // offset was beyond EOF
          in.close();
          return new ByteArrayInputStream(new byte[0]);
        }
      }
      return ByteStreams.limit(in, length);
    }

    @Override
    public ByteSource slice(long offset, long length) {
      checkArgument(offset >= 0, "offset (%s) may not be negative", offset);

	if b.r > 0 {
		copy(b.buf, b.buf[b.r:b.w])
		b.w -= b.r
		b.r = 0
	}

	if b.w >= len(b.buf) {
		panic("bufio: tried to fill full buffer")
	}

	// Read new data: try a limited number of times.
	for i := maxConsecutiveEmptyReads; i > 0; i-- {
		n, err := b.rd.Read(b.buf[b.w:])
		if n < 0 {
			panic(errNegativeRead)
		}
		b.w += n
		if err != nil {
			b.err = err
			return

		HTTPStatusCode: http.StatusServiceUnavailable,
	},
	ErrMaxVersionsExceeded: {
		Code:           "MaxVersionsExceeded",
		Description:    "You've exceeded the limit on the number of versions you can create on this object",
		HTTPStatusCode: http.StatusBadRequest,
	},
	ErrInvalidPrefixMarker: {
		Code:           "InvalidPrefixMarker",

  @SuppressWarnings("DistinctVarargsChecker") // test of buggy call
  public void testExplicit_withDuplicates() {
    assertThrows(IllegalArgumentException.class, () -> Ordering.explicit(1, 2, 3, 4, 2));
  }

  // A more limited test than the one that follows, but this one uses the
  // actual public API.
  @J2ktIncompatible // Ordering.arbitrary
  public void testArbitrary_withoutCollisions() {
    List<Object> list = new ArrayList<>();

  @SuppressWarnings("DistinctVarargsChecker") // test of buggy call
  public void testExplicit_withDuplicates() {
    assertThrows(IllegalArgumentException.class, () -> Ordering.explicit(1, 2, 3, 4, 2));
  }

  // A more limited test than the one that follows, but this one uses the
  // actual public API.
  @J2ktIncompatible // Ordering.arbitrary
  public void testArbitrary_withoutCollisions() {
    List<Object> list = new ArrayList<>();

        "stopwords": "_english_"
      },
      "content_length_filter": {
        "type": "length",
        "max": 30
      },
      "limit_token_count_filter": {
        "type": "limit",
        "max_token_count": 2147483647
      },
      "stemmer_en_filter": {
        "type": "stemmer",
        "name": "english"
      },
      "arabic_stop": {
        "type":       "stop",

   * To differentiate the two cases we ping the server when a stream times out. If the overall
   * connection is fine the ping will receive a pong; otherwise it won't.
   *
   * The deadline to respond to this ping attempts to limit the cost of being wrong. If it is too
   * long, streams created while we await the pong will reuse broken connections and inevitably
   * fail. If it is too short, slow connections will be marked as failed and extra TCP and TLS

</details>

这里，我们使用 `SessionDep` 依赖项（一个 `Session` ）将新的 `Hero` 添加到 `Session` 实例中，提交更改到数据库，刷新 hero 中的数据，并返回它。

### 读取 Hero 类

我们可以使用 `select()` 从数据库中**读取** `Hero` 类，并利用 `limit` 和 `offset` 来对结果进行分页。

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[48:55] hl[51:52,54] *}

### 读取单个 Hero

我们可以**读取**单个 `Hero` 。

        }

        refresh();
    }

    /**
     * Generates a unique ID for a document based on session ID and URL.
     * Uses hashing for long IDs to ensure they fit within OpenSearch limits.
     *
     * @param sessionId The session ID.
     * @param url The URL.
     * @return The generated unique ID.
     */
    private String getId(final String sessionId, final String url) {