利用Applet请求服务

public class ConnectionHelper {

	private HttpURLConnection conn;

	ConnectionHelper(String urlStr) throws IOException {
		URL serverUrl = new URL(urlStr);
		// open Socket connection.
		conn = (HttpURLConnection) serverUrl.openConnection();
		conn.setRequestMethod("POST");
		conn.setAllowUserInteraction(true);
		conn.setDoInput(true);
		conn.setDoOutput(true);
		conn.setUseCaches(true);
		conn.setRequestProperty("Content-Type", "application/octet-stream");
	}

	HttpURLConnection getConnection() {
		return conn;
	}

}

使用，下面的代码可以将图片从applet上传到服务器：

ConnectionHelper connHelper = new ConnectionHelper(urlStr);
		// open Socket connection.
		HttpURLConnection conn = connHelper.getConnection();

		if (null != image) {
			BufferedImage bufImg = new BufferedImage(image.getWidth(this),
					image.getHeight(this), BufferedImage.TYPE_3BYTE_BGR);
			Graphics2D g2d = bufImg.createGraphics();
			g2d.drawImage(image, 0, 0, this);
			ImageIO.write(bufImg, "jpg", conn.getOutputStream());
		} else {
			OutputStream outStream = conn.getOutputStream();
			InputStream inStream = new FileInputStream(localImageFile);

			byte[] b = new byte[1024 * 1024];
			int bytes = 0;

			while ((bytes = inStream.read(b)) > 0) {
				outStream.write(b, 0, bytes);
			}
			inStream.close();
		}