Question

How to get file properties (e.g. date) without downloading file if I have URL of the file.

I have to implement updates checker. For this purpose I’m going to compare dates of two files. One is local, the second is the same file but with latest date on server. I know URL to the second file.

Please, give me a peace of advice – how to check date of the second file without downloading it?

I have thought about comparing via hash, but I need to check whether file on server is latest version or not?

Answer 1

To check the file date you can use this snippet of code

try {
  URL url = new URL(inputFile);
  URLConnection urlConnection = url.openConnection();
  System.out.println("Date= "+new Date(urlConnection.getLastModified()));
  System.out.println("Size= "+urlConnection.getContentLength());

} catch (MalformedURLException e1) {
  e1.printStackTrace();  //Todo change body of catch statement.
} catch (IOException e1) {
  e1.printStackTrace();  //Todo change body of catch statement.
}

with the attributes of date, size, name you can identify the resource.