Method copy

guava/src/com/google/common/io/ByteStreams.java:108–123

Copies all bytes from the input stream to the output stream. Does not close or flush either stream. <p><b>Java 9 users and later:</b> this method should be treated as deprecated; use the equivalent {@link InputStream#transferTo} method instead. @param from the input stream to read from @param to t

(InputStream from, OutputStream to)

   * @throws IOException if an I/O error occurs
   */
  @CanIgnoreReturnValue
  public static long copy(InputStream from, OutputStream to) throws IOException {
    checkNotNull(from);
    checkNotNull(to);
    byte[] buf = createBuffer();
    long total = 0;
    while (true) {
      int r = from.read(buf);
      if (r == -1) {
        break;
      }
      to.write(buf, 0, r);
      total += r;
    }
    return total;
  }

  /**
   * Copies all bytes from the readable channel to the writable channel. Does not close or flush