import org.apache.tools.zip.ZipEntry;
import org.apache.tools.zip.ZipOutputStream;
import org.apache.tools.zip.ZipOutputStream.UnicodeExtraFieldPolicy;


public class ArchiveDownloadServlet extends AbstractServlet {
//.....

protected void executeSVNOperation(IDataProvider dataProvider, State state)
			throws SVNWebClientException {
		AbstractRequestHandler requestHandler = this.getRequestHandler(state
				.getRequest());

		// init

		long revision;
		String url;
		if (requestHandler.getCurrentRevision() != -1) {
			revision = requestHandler.getCurrentRevision();
		} else {
			revision = dataProvider.getHeadRevision();
		}
		String strUrl = requestHandler.getUrl();
		if (strUrl.length() > 0 && !strUrl.endsWith("/"))
			strUrl = strUrl + '/';

		if (requestHandler.getPegRevision() != -1) {
			strUrl = dataProvider.getLocation(requestHandler.getUrl(),
					requestHandler.getPegRevision(), revision);
		}
		url = strUrl;
		DataRepositoryElement info = dataProvider.getInfo(url, revision);

		// execute

		ZipOutputStream zos = null;
		try {
			String encoding = configurationProvider.getZipEncoding();
			String defaultEncoding = configurationProvider.getDefaultEncoding();

			try {
				String tmp = "";
				tmp.getBytes(encoding);
			} catch (UnsupportedEncodingException ue) {
				Logger.getLogger(this.getClass()).error(ue, ue);
				encoding = "ISO-8859-1";
			}

			try {
				String tmp = "";
				tmp.getBytes(defaultEncoding);
			} catch (UnsupportedEncodingException ue) {
				Logger.getLogger(this.getClass()).error(ue, ue);
				defaultEncoding = "ISO-8859-1";
			}

			if (state.getRequest().getHeader("User-Agent") != null) {
				String userAgent = state.getRequest().getHeader("User-Agent");
				if (userAgent.indexOf("Linux") > -1) {
					encoding = "UTF-8";
					defaultEncoding = "UTF-8";
				} else if (userAgent.indexOf("Win32") > -1 || userAgent.indexOf("Windows") > -1){
					encoding = "GBK";
					defaultEncoding = "GBK";
				}
			}

			HttpServletResponse response = state.getResponse();
			OutputStream out = response.getOutputStream();

			zos = new ZipOutputStream(out);
			zos.setMethod(ZipOutputStream.DEFLATED);
			zos.setEncoding(encoding);


			if (encoding.equals("UTF-8")) {
				 zos.setCreateUnicodeExtraFields(UnicodeExtraFieldPolicy.ALWAYS);
			}

			String mimeType = "application/octet-stream";
			response.setContentType(mimeType);

			String fileName = info.getName();
			fileName = fileName + "-r" + Long.toString(info.getRevision())
					+ ".zip";

			String zipnameEncoding = ContentEncodingHelper.getEncoding(state,
					defaultEncoding);

			fileName = new String(fileName.getBytes(zipnameEncoding),
					"ISO-8859-1");

			if (state.getRequest().getHeader("User-Agent") != null) {
				if (state.getRequest().getHeader("User-Agent").indexOf("MSIE") < 0) {
					fileName = "\"" + fileName + "\"";
				}
			}
			response.setHeader("Content-Disposition", "attachment; filename="
					+ fileName);

			DataDirectoryElement dir = dataProvider.getDirectory(url, revision,
					false);
			this.processFolder(dataProvider, zos, dir, "", url);

			zos.flush();
		} catch (Exception ie) {
			throw new SVNWebClientException(ie);
		} finally {
			if (zos != null) {
				try {
					zos.close();
				} catch (Exception e) {
				}
			}
		}
	}

//...

}