Java

Get the Last-Modified Date Before HTTP Download

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Demonstrates how to send a HEAD request to get the last-modified date of a file on a web server (without downloading the file). Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    CkHttp http = new CkHttp();

    CkHttpResponse resp = new CkHttpResponse();
    success = http.HttpNoBody("HEAD","https://www.chilkatsoft.com/hamlet.xml",resp);
    if (success == false) {
        System.out.println(http.lastErrorText());
        return;
        }

    // Examine the response header.
    System.out.println(resp.header());

    // Here is a sample response header:

    // 	Content-Length: 279658
    // 	Content-Type: text/xml
    // 	Last-Modified: Thu, 12 May 2016 15:14:08 GMT
    // 	Accept-Ranges: bytes
    // 	ETag: "c1cd8bee60acd11:0"
    // 	Server: Microsoft-IIS/8.5
    // 	X-Powered-By: ASP.NET
    // 	X-Powered-By-Plesk: PleskWin
    // 	Date: Thu, 25 Jul 2019 16:40:54 GMT

    // Get the Last-Modified header.
    String lastModStr = resp.getHeaderField("Last-Modified");
    // If the header exists...
    if (resp.get_LastMethodSuccess() == true) {
        // Parse the RFC822 format date/time string
        CkDateTime ckdt = new CkDateTime();
        ckdt.SetFromRfc822(lastModStr);

        // If we want to access individual date/time parts (in the local timezone)
        CkDtObj dt = new CkDtObj();
        ckdt.ToDtObj(true,dt);

        System.out.println("day/month/year = " + dt.get_Day() + "/" + dt.get_Month() + "/" + dt.get_Year());
        }
  }
}