从URL获取文件名时如何解决空名

Question

我正在尝试创建一种获取URL并返回文件名的方法。 我试图在另一种方法中使用System.out.println(Utility.getName("www.site.com/myfile.zip")); 但它返回空。 我该如何解决？

public class Utility {

    public static String getName(String fileURL)
            throws IOException {
        URL url = new URL(fileURL);
        HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
        int responseCode = httpConn.getResponseCode();
        String fileName = "";

        // always check HTTP response code first
        if (responseCode == HttpURLConnection.HTTP_OK) {

            String disposition = httpConn.getHeaderField("Content-Disposition");

            if (disposition != null) {
                // extracts file name from header field
                int index = disposition.indexOf("filename=");
                if (index > 0) {
                    fileName = disposition.substring(index + 10,
                            disposition.length() - 1);
                }
            } else {
                // extracts file name from URL
                fileName = fileURL.substring(fileURL.lastIndexOf("/") + 1,
                        fileURL.length());
            }
        }
        return fileName;
    }
}