simple sample client for fileupload to dl, requires commons-httpclient and it's dependencies.

FileUploadSample.java

import java.io.File;
import java.io.IOException;

import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.UsernamePasswordCredentials;
import org.apache.commons.httpclient.auth.AuthScope;
import org.apache.commons.httpclient.cookie.CookiePolicy;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.multipart.FilePart;
import org.apache.commons.httpclient.methods.multipart.MultipartRequestEntity;
import org.apache.commons.httpclient.methods.multipart.Part;
import org.apache.commons.httpclient.methods.multipart.StringPart;
import org.apache.commons.httpclient.params.HttpMethodParams;

public class FileUploadTest {

	public static void main(String[] args) throws Exception {
		if (args.length != 6) {
			System.out.println(
				"\nUsage: java -classpath " +
					"./:commons-httpclient.jar:commons-logging.jar:commons-codec.jar " +
						"FileUploadTest <host> <port> <login> <password> " +
							"<groupId> <file>");

			return;
		}

		FileUploadTest fue = new FileUploadTest();

		String host = args[0];
		int port = Integer.parseInt(args[1]);
		String login = args[2];
		String password = args[3];
		long groupId = Long.parseLong(args[4]);
		File file = new File(args[5]);

		if (file.exists() && !file.isDirectory()) {
			fue.update(host, port, login, password, groupId, file);
		}
	}

	public void update(
			String host, int port, String login, String password, long groupId,
			File file)
		throws HttpException, IOException {

		HttpClient client = new HttpClient();

		client.getState().setCredentials(
			new AuthScope(host, 8080, "PortalRealm"),
			new UsernamePasswordCredentials(login, password));

		PostMethod method = new PostMethod(
			"http://" + host +
				((port > 0) && (port < 65535) ? ":" + port : "") +
					"/tunnel-web/secure/jsonws/dlapp/add-file-entry");

		method.getParams().setParameter(
			HttpMethodParams.RETRY_HANDLER,
			new DefaultHttpMethodRetryHandler(3, false));
		method.getParams().setCookiePolicy(CookiePolicy.RFC_2109);

		Part[] parts = new Part[] {
			new StringPart("repositoryId", String.valueOf(groupId)),
			new StringPart("folderId", "0"),
			new StringPart("sourceFileName", file.getName()),
			new StringPart("mimeType", ""),
			new StringPart("title", file.getName()),
			new StringPart("description", ""),
			new StringPart("changeLog", ""),
			new FilePart("file", file.getName(), file)
		};

		method.setRequestEntity(
			new MultipartRequestEntity(parts, method.getParams())
		);

		try {
			method.setDoAuthentication(true);

			int statusCode = client.executeMethod(method);

			String responseBody = new String(method.getResponseBody());

			if (statusCode != HttpStatus.SC_OK) {
				throw new HttpException(method.getStatusLine().toString());
			}
			else {
				System.out.println(responseBody);
			}
		}
		finally {
			method.releaseConnection();
		}
	}

}