示例#1
0
  /**
   * Retrieves a file from a given URL and saves it to the outputPath.
   *
   * @param url the URL of the file to download
   * @param outputPath the path to the save the file to
   * @param useProxy whether to use the configured proxy when downloading files
   * @throws DownloadFailedException is thrown if there is an error downloading the file
   */
  public static void fetchFile(URL url, File outputPath, boolean useProxy)
      throws DownloadFailedException {
    if ("file".equalsIgnoreCase(url.getProtocol())) {
      File file;
      try {
        file = new File(url.toURI());
      } catch (URISyntaxException ex) {
        final String msg = format("Download failed, unable to locate '%s'", url.toString());
        throw new DownloadFailedException(msg);
      }
      if (file.exists()) {
        try {
          org.apache.commons.io.FileUtils.copyFile(file, outputPath);
        } catch (IOException ex) {
          final String msg =
              format(
                  "Download failed, unable to copy '%s' to '%s'",
                  url.toString(), outputPath.getAbsolutePath());
          throw new DownloadFailedException(msg);
        }
      } else {
        final String msg = format("Download failed, file ('%s') does not exist", url.toString());
        throw new DownloadFailedException(msg);
      }
    } else {
      HttpURLConnection conn = null;
      try {
        LOGGER.debug("Attempting download of {}", url.toString());
        conn = URLConnectionFactory.createHttpURLConnection(url, useProxy);
        conn.setRequestProperty("Accept-Encoding", "gzip, deflate");
        conn.connect();
        int status = conn.getResponseCode();
        int redirectCount = 0;
        while ((status == HttpURLConnection.HTTP_MOVED_TEMP
                || status == HttpURLConnection.HTTP_MOVED_PERM
                || status == HttpURLConnection.HTTP_SEE_OTHER)
            && MAX_REDIRECT_ATTEMPTS > redirectCount++) {
          final String location = conn.getHeaderField("Location");
          try {
            conn.disconnect();
          } finally {
            conn = null;
          }
          LOGGER.debug("Download is being redirected from {} to {}", url.toString(), location);
          conn = URLConnectionFactory.createHttpURLConnection(new URL(location), useProxy);
          conn.setRequestProperty("Accept-Encoding", "gzip, deflate");
          conn.connect();
          status = conn.getResponseCode();
        }
        if (status != 200) {
          try {
            conn.disconnect();
          } finally {
            conn = null;
          }
          final String msg =
              format(
                  "Error downloading file %s; received response code %s.", url.toString(), status);
          throw new DownloadFailedException(msg);
        }
      } catch (IOException ex) {
        try {
          if (conn != null) {
            conn.disconnect();
          }
        } finally {
          conn = null;
        }
        final String msg = format("Error downloading file %s; unable to connect.", url.toString());
        throw new DownloadFailedException(msg, ex);
      }

      final String encoding = conn.getContentEncoding();
      BufferedOutputStream writer = null;
      InputStream reader = null;
      try {
        if (encoding != null && "gzip".equalsIgnoreCase(encoding)) {
          reader = new GZIPInputStream(conn.getInputStream());
        } else if (encoding != null && "deflate".equalsIgnoreCase(encoding)) {
          reader = new InflaterInputStream(conn.getInputStream());
        } else {
          reader = conn.getInputStream();
        }

        writer = new BufferedOutputStream(new FileOutputStream(outputPath));
        final byte[] buffer = new byte[4096];
        int bytesRead;
        while ((bytesRead = reader.read(buffer)) > 0) {
          writer.write(buffer, 0, bytesRead);
        }
        LOGGER.debug("Download of {} complete", url.toString());
      } catch (IOException ex) {
        analyzeException(ex);
        final String msg =
            format(
                "Error saving '%s' to file '%s'%nConnection Timeout: %d%nEncoding: %s%n",
                url.toString(), outputPath.getAbsolutePath(), conn.getConnectTimeout(), encoding);
        throw new DownloadFailedException(msg, ex);
      } catch (Throwable ex) {
        final String msg =
            format(
                "Unexpected exception saving '%s' to file '%s'%nConnection Timeout: %d%nEncoding: %s%n",
                url.toString(), outputPath.getAbsolutePath(), conn.getConnectTimeout(), encoding);
        throw new DownloadFailedException(msg, ex);
      } finally {
        if (writer != null) {
          try {
            writer.close();
          } catch (IOException ex) {
            LOGGER.trace("Error closing the writer in Downloader.", ex);
          }
        }
        if (reader != null) {
          try {
            reader.close();
          } catch (IOException ex) {
            LOGGER.trace("Error closing the reader in Downloader.", ex);
          }
        }
        try {
          conn.disconnect();
        } finally {
          conn = null;
        }
      }
    }
  }
 public int getConnectTimeout() {
   return _flddelegate.getConnectTimeout();
 }