Thread: getting files in the linux server

Hello Truffy,

Do you know the location of the log files? What do you wish to do with the file once you have it?

Hello Truffy,

Here is a simple example. It will read in a file called log.txt and print it's content to the console:

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
 
public class Truffy {
 
    /**
     * JavaProgrammingForums.com
     */
 
    // Path to log file . = application root
    private static String path = ".";
 
    // Log file name
    private static String file = "log.txt";
 
    public void getAndReadFile(){
 
          try
          {
          FileInputStream in = new FileInputStream(path + "/" + file);
          BufferedReader br = new BufferedReader(new InputStreamReader(in));
          String strLine;
 
          // Read file line by line
          // Processing would be called here
          while((strLine = br.readLine())!= null)
          {
           System.out.println(strLine);
          }
 
          }catch(Exception e){
           System.out.println(e);
          }
 
    }
 
 
    public static void main(String[] args) {
 
        Truffy t = new Truffy();
        t.getAndReadFile();
 
    }
 
}

You can change the location of the file by editing the path String and the name of the log file by editing the file String.

Originally Posted by Truffy

so given that it need an authentication, how will the code will be? thank you.

Do you have access to this file before you run the Java program?

Originally Posted by Truffy

yeah. actually i get it using WinSCP3.

OK in that case your user has access to the path/file in question.

Are you running this application in a Linux environment?

If so, I'm thinking it could be something to do with the path String.

private static String path = "////10.123.456.78//apps//user//staging//M//log";

Why so many / at the beginning?

If you are not running this from within Linux, you can't just run this in Windows and expect it to grab the file from a linux box. There needs to be some kind of authentication process.

Why not login to the Linux box and launch the application from there?

Hello Truffy,

You said you normally use WinSCP to connect to the linux box. Does that mean you can connect via FTP?

If so, you could try this code. You may need to edit it slightly.

import java.io.*;
import java.net.URL;
import java.net.URLConnection;
 
public class JFTP {
 
    /**
     * JavaProgrammingForums.com
     */
 
    public static String server = "10.123.456.78";
    public static String userName = "username";
    public static String password = "password";
    public static String fileName = "apps/user/staging/M/log/success.log";
 
    public static void main(String[] args) throws Exception{
 
    System.out.println("Connecting to FTP server...");    
 
    //Connection String
    URL url = new URL("ftp://"+userName+":"+password+"@"+server+"/"+fileName+";type=i");
    URLConnection con = url.openConnection();
 
    //Add error handling here for non connections
    System.out.println("Connected.");
 
    BufferedInputStream in = new BufferedInputStream(con.getInputStream());
 
    System.out.println("Downloading file.");
 
    //Downloads the selected file to the C drive
    FileOutputStream out = new FileOutputStream("C:\\success.log");
 
    int i = 0;
    byte[] bytesIn = new byte[1024];
    while ((i = in.read(bytesIn)) >= 0) {
        out.write(bytesIn, 0, i);
    }
    out.close();
    in.close();
 
    System.out.println("File downloaded to C drive");
 
    }
 
}

Originally Posted by JavaPF

Hello Truffy,

You said you normally use WinSCP to connect to the linux box. Does that mean you can connect via FTP?

If so, you could try this code. You may need to edit it slightly.

import java.io.*;
import java.net.URL;
import java.net.URLConnection;
 
public class JFTP {
 
    /**
     * JavaProgrammingForums.com
     */
 
    public static String server = "10.123.456.78";
    public static String userName = "username";
    public static String password = "password";
    public static String fileName = "apps/user/staging/M/log/success.log";
 
    public static void main(String[] args) throws Exception{
 
    System.out.println("Connecting to FTP server...");    
 
    //Connection String
    URL url = new URL("ftp://"+userName+":"+password+"@"+server+"/"+fileName+";type=i");
    URLConnection con = url.openConnection();
 
    //Add error handling here for non connections
    System.out.println("Connected.");
 
    BufferedInputStream in = new BufferedInputStream(con.getInputStream());
 
    System.out.println("Downloading file.");
 
    //Downloads the selected file to the C drive
    FileOutputStream out = new FileOutputStream("C:\\success.log");
 
    int i = 0;
    byte[] bytesIn = new byte[1024];
    while ((i = in.read(bytesIn)) >= 0) {
        out.write(bytesIn, 0, i);
    }
    out.close();
    in.close();
 
    System.out.println("File downloaded to C drive");
 
    }
 
}

hi,

i already try the code. and here's the error:

init:
deps-jar:
compile-single:
run-single:
Connecting to FTP server...
Connected.
Exception in thread "main" java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl .java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSoc ketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.j ava:182)
at java.net.Socket.connect(Socket.java:520)
at java.net.Socket.connect(Socket.java:470)
at sun.net.NetworkClient.doConnect(NetworkClient.java :157)
at sun.net.NetworkClient.openServer(NetworkClient.jav a:118)
at sun.net.ftp.FtpClient.openServer(FtpClient.java:48 8)
at sun.net.ftp.FtpClient.openServer(FtpClient.java:47 5)
at sun.net.http://www.protocol.ftp.FtpURLConnec...ction.java:270)
at sun.net.http://www.protocol.ftp.FtpURLConnec...ction.java:352)
at aa.JFTP.main(JFTP.java:29)
Java Result: 1
BUILD SUCCESSFUL (total time: 1 second)

i dont know why it is not working.

Good morning Truffy,

I'm glad that code is working with the new server.

Originally Posted by Truffy

the next part of it is since it is a server logs, if someone transact on it, my program have to know it. how can i add a listen to it? is there any refresh commands to it? or compare commands?

So you want to watch the log file and when it is changed, your application does something?

How about this code. It will watch the log file every 5 seconds and if it changes size, the doSomething() method is called.

import java.io.*;
 
public class TruffyLog {
 
    /**
     * JavaProgrammingForums.com
     */
     public static long StartSize;
 
     public long getFileSize(String filename) {
 
            File file = new File(filename);
 
            if (!file.exists() || !file.isFile()) {
              System.out.println("File doesn\'t exist");
              return -1;
            }
            return file.length();
          }
 
 
     public static void doSomething(){
 
         System.out.println("Log file has been changed");
 
     }
 
 
    public static void main(String[] args) throws Exception{
 
        System.out.println("Watching file");
 
        TruffyLog tl = new TruffyLog();
        long size = tl.getFileSize("success.log");
        StartSize = size;
        System.out.println("Start size: " + StartSize);
 
        while(true){
        size = tl.getFileSize("success.log");
        System.out.println("Filesize in bytes: " + size + " - No change");
        //If file size changes...
        if(size < StartSize | size > StartSize){
            doSomething();
            StartSize = size;
        }
        // Sleep 5 seconds
        Thread.sleep(5000);
        }
 
    }
 
}

Originally Posted by Truffy

i have a question re the above code. since tha is using ftp, what if i am downloading large files live 100MB and the server is far from my workplace. how can i solved the latency and delays of it?

I haven't tested that code on large files but as far as im aware, it will download them as fast as your internet connection will allow. I'm not sure how you would make the process faster.

Originally Posted by Truffy

heres the problem: whenever the file changed. another GUI shows and if the file changed for ten times, there will be ten GUI. and i only want 1 GUI. and it will only refresh the present GUI.

how can i do that?

Try this. I have used a boolean variable which is set to false at run time. When the log file is changed for the first time, the createAndShowGUI method is run and the boolean variable is set to true. When the log file changes again, the if statement checks to see if the boolean variable is true. If it is true then the program knows to run the refreshGUI method instead of the createAndShowGUI method.

import java.io.*;
 
public class TruffyLog {
 
    /**
     * JavaProgrammingForums.com
     */
     public static long StartSize;
     private static boolean on = false;
 
     public long getFileSize(String filename) {
 
            File file = new File(filename);
 
            if (!file.exists() || !file.isFile()) {
              System.out.println("File doesn\'t exist");
              return -1;
            }
            return file.length();
          }
 
 
     public static void doSomething(){
 
         System.out.println("Log file has been changed");
         ex tryME = new ex();
         if(on == false){
         System.out.println("NEW GUI");
         tryME.createAndShowGUI();
         on = true;
         }
         else if(on == true){
             System.out.println("REFRESH GUI");
             tryME.refreshGUI();
         }
 
     }
 
 
    public static void main(String[] args) throws Exception{
 
        System.out.println("Watching file");
 
        TruffyLog tl = new TruffyLog();
        long size = tl.getFileSize("C:\\success.log");
        StartSize = size;
        System.out.println("Start size: " + StartSize);
 
        while(true){
        size = tl.getFileSize("C:\\success.log");
        System.out.println("Filesize in bytes: " + size + " - No change");
        //If file size changes...
        if(size < StartSize | size > StartSize){
            doSomething();
            StartSize = size;
        }
        // Sleep 5 seconds
        Thread.sleep(5000);
        }
 
    }
 
}

import javax.swing.JFrame;
import javax.swing.*;
 
public class ex {
 
    public static JFrame frame = new JFrame("Hello Java Forums!!!");
    public static JLabel label;
 
    public static void createAndShowGUI() {
 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        label = new JLabel("Hello Java forums");
        frame.add(label);
        frame.setSize(300, 200);
        frame.setVisible(true);
    }
 
    public static void refreshGUI(){
 
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.remove(label);
        JLabel label2 = new JLabel("JAVA PROGRAMMING FORUMS!");
        frame.add(label2);
        frame.setSize(300, 200);
        frame.setVisible(true);
 
    }
 
    /*
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    };
    */
}