Problem running 3rd party provided Java code, main method not found in class

[Mark Alderson]

Hi,

Firstly, I'm a total noob to Java, spent some time with Java and Oracle back at Uni over 10 years ago, however my profession these days keeps me well and truly planted in the Microsoft world (I'm a SQL DBA by rights).. so you may be asking what am I doing messing around with Java..

Long story short, I need to download a file from a web server from a 3rd party vendor, and build this into a nightly package which after downloading the file will extract it, import the data into various tables in a DB etc. The 3rd party has provided me with the following files/code as a method of automating the download of the files, however I'm having problems compiling/running them, and I imagine it's probably just because I don't really have any idea what I'm doing with Java. I have spent several hours on Google, and quite a lot of searches have brought me to your site, but I haven't quite managed to find a resolution to my specific problem, so here goes

First, here are the 2 java files that I was given

iDownload.java

package LRMP;

import java.io.IOException;
import java.net.MalformedURLException;

public interface iDownload {	
	void login(String webSiteUsername,String webSitePassword)
            throws MalformedURLException, IOException;
	void download(String outFolder)
            throws MalformedURLException, IOException;
}

impDownload.java

package LRMP;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Calendar;
import javax.net.ssl.HttpsURLConnection;

/**
* 
* Returns either the location of the downloaded file,
 * an error to say it couldn't find the file or an error to say it couldn't log in. 
**/

public class impDownload implements iDownload{
    private static final String PROTOCOL = "";
    private static final String HOST = "";
    private static final String URL = PROTOCOL + "://" + HOST;
    private static final String URL_LOGIN = "";
    private static final String URL_DOWNLOAD = "";
    private static final String URL_FILES = "";
    private static final String FILE_NAME = "" +
             String.format("%1$tY%2td%1$tm", Calendar.getInstance());
    private static boolean loginFailed = false;
    private static boolean isLatestFileFound = false;

    
    //NOTE: These should be set to the username
   // and password and to the location to which the file should be downloaded
    private static String username = "";
    private static String password = "";    
    private static String location = "C:\\" ;
    
    
    private String fileURL;
    private String jsession;

	/**
	 * @param args String Username, String Password, String outFolder
	 */
    public static void main(String[] args) {

        try {
                new impDownload().run(username,password,location);
                if(isLatestFileFound) {
                }
                else if (loginFailed){
                		
                	System.out.println(
                            String.format("%1$tY-%1$tm-%2td %1$tH:%1$tM:%1$tS\t",
                                    Calendar.getInstance()) +
                                   "Authorisation Failed"
                            );
                }
                else {
                        // no file to process
                        System.out.println(
                               String.format(
                                   "%1$tY-%1$tm-%2td %1$tH:%1$tM:%1$tS\t",
                                    Calendar.getInstance()) +
                                              "No file found to process"
                                       );
                }
        }
        catch(Exception e) {
                // something went wrong
                String msg = 
                     "An error occured during the import.\n\n" + e.toString();                
                e.printStackTrace(System.err);
        }
 }
    
    
    public void run(String webSiteUsername, String webSitePassword, String outFolder )
            throws Exception {    
        login(webSiteUsername,webSitePassword);
        if(isLatestFileFound) {
                download(outFolder);
        }

 }

 public void login(String webSiteUsername,String webSitePassword)
           throws MalformedURLException, IOException {

        // build login request
        HttpsURLConnection huc = 
               (HttpsURLConnection) new URL(URL + URL_LOGIN).openConnection();
        huc.setDoOutput(true);
        huc.setRequestMethod("POST");
        huc.setRequestProperty("Content-Type",
              "application/x-www-form-urlencoded");
        OutputStream os = huc.getOutputStream();
        os.write(("password=" + webSitePassword +
              "&submit:login=Login&username=" + webSiteUsername).getBytes("UTF-8"));
        os.flush();
        os.close();
        huc.connect();

        // parse content of the page
        BufferedReader br = new BufferedReader(new InputStreamReader(huc.getInputStream()));
        String line;
        while((line = br.readLine()) != null) {

                // get file URL and session ID
                if(line.contains(FILE_NAME)) {

                        int i0 = line.indexOf(URL_DOWNLOAD);
                        int i1 = line.indexOf("jsessionid=");
                        int i2 = line.indexOf("?path=");
                        int i3 = line.indexOf(" >" + FILE_NAME);

                        isLatestFileFound = true;
                        fileURL = URL + line.substring(i0, i1 - 1) + line.substring(i2, i3 - 1);
                        jsession = line.substring(i1 + 11, i2);
                        break;
                }
                
                if(line.contains("User name cannot be null") ||
                     line.contains("Password cannot be null") ||
                     line.contains("The user name was not found") ||
                     line.contains("Authorisation failed"))                		
                {
                   loginFailed = true;			
                }
                
                
        }
        br.close();
        huc.disconnect();
 }

 public void download(String outFolder)
           throws MalformedURLException, IOException {

        HttpsURLConnection huc = 
          (HttpsURLConnection) new URL(fileURL).openConnection();
        huc.setRequestMethod("GET");
        huc.setRequestProperty("Host", HOST);
        huc.setRequestProperty("User-Agent", "JVM");
        huc.setRequestProperty("Accept",
                "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
        huc.setRequestProperty("Accept-Language", "en-gb,en;q=0.5");
        huc.setRequestProperty("Accept-Encoding", "gzip,deflate");
        huc.setRequestProperty("Accept-Charset",
               "ISO-8859-1,utf-8;q=0.7,*;q=0.7");
        huc.setRequestProperty("Keep-Alive", "300");
        huc.setRequestProperty("Connection", "keep-alive");
        huc.setRequestProperty("Referer", URL + URL_FILES);
        huc.setRequestProperty("Cookie", "JSESSIONID=" + jsession);
        huc.connect();

        // save file on disk
        byte[] buffer = new byte[4096];
        File file = new File(outFolder + FILE_NAME + ".zip");
        FileOutputStream fos = new FileOutputStream(file);
        int bytes;
        InputStream is = huc.getInputStream();
        while(true) {
                bytes = is.read(buffer);
                if(bytes <= 0)
                        break;
                fos.write(buffer, 0, bytes);
        }
        fos.close();

        huc.disconnect();
        System.out.println(
                String.format("%1$tY-%1$tm-%2td %1$tH:%1$tM:%1$tS\t",
                     Calendar.getInstance()) +
                       "File downloaded to "+ outFolder + FILE_NAME + ".zip"
                );
 }



}

Please note I have blanked out alot of the variables for security measures

Next I have created a .bat file and am calling this from command prompt

run.bat

cls
cd /d "C:\Users\aldersom\Desktop\SFTS_AUTODOWNLOAD\src\LRMP"
javac iDownload.java
cd /d "C:\Users\aldersom\Desktop\SFTS_AUTODOWNLOAD\src"
java LRMP.iDownload
cd /d "C:\Users\aldersom\Desktop\SFTS_AUTODOWNLOAD"

When I run this, I get the following 'errors'

C:\Users\aldersom\Desktop\SFTS_AUTODOWNLOAD>cd /d "C:\Users\aldersom\Desktop\SFT
S_AUTODOWNLOAD\src\LRMP"

C:\Users\aldersom\Desktop\SFTS_AUTODOWNLOAD\src\LRMP>javac iDownload.java

C:\Users\aldersom\Desktop\SFTS_AUTODOWNLOAD\src\LRMP>cd /d "C:\Users\aldersom\De
sktop\SFTS_AUTODOWNLOAD\src"

C:\Users\aldersom\Desktop\SFTS_AUTODOWNLOAD\src>java LRMP.iDownload
Error: Main method not found in class LRMP.iDownload, please define the main met
hod as:
   public static void main(String[] args)CycleClips <cycleclips@ctc.

I've tried various different things, but I've got a feeling I'm simply not doing this the correct way.

For further information I'm running JDK 1.7.0_09, althought you've probably gather that from the paths in the code above.

Let me know if there's any further information you require. Any help will be much appreciated!

Many thanks
Mark

[Stuart A. Burkett]

The class you should be trying to compile and run is LRMP.impDownload, not LRMP.iDownload.

[Richard Tookey]

You should be compiling and executing the class impDownload not just compiling the interface iDownload and then trying to execute it!

[Mark Alderson]

thanks for the input fellas!

OK, if I now try to compile the impDownload.java, I get the following

C:\Users\aldersom\Desktop\SFTS_AUTODOWNLOAD\src\LRMP>javac impDownload.java
impDownload.java:19: error: cannot find symbol
public class impDownload implements iDownload{
                                    ^
  symbol: class iDownload
1 error

[sai rama krishna]

symbol: class iDownload


It is interface. I wonder why it is saying as class.

[Kemal Sokolovic]

sai rama krishna wrote: symbol: class iDownload

It is interface. I wonder why it is saying as class.

Because that's the error message compiler produces in when interface, class or method cannot be found.

@OP:
Did you try to compile from the root directory of your source? Since both interface and class implementing it are in LRPM package, navigate to src directory and try:

~/src$ javac LRPM/impDownload.java

[Mark Alderson]

Sweet! Thanks Kemal, your advice was correct, by compiling the entire source folder and then executing the package I was successful.

Muchos gracias

[Kemal Sokolovic]

Glad I could help! And welcome to the Ranch!