Find and query files in a directory in date format yyymmdd

[hm9]

Hi

I have a directory where log txt files are logged. Each log file has the following title date format 20180114.log, which is yyymmdd.

I want to search for data in the preceding file (date) so if the current date file is 20180114.log, I want to search the previous day 20180113.log, and then output the data i search for in anther text file.

How do I achieve this in java? any code examples I can follow?

I made a start by displaying the list of the files in the directory but could do with some help to achieve the above

public static void main(String[] args) {
File currentDir = new File("\\\\directory Path"); // current directory
displayDirectoryContents(currentDir);
}

public static void displayDirectoryContents(File dir) {
try {
File[] files = dir.listFiles();
for (File file : files) {

System.out.println(" file:" + file.getCanonicalPath());
}

} catch (IOException e) {
e.printStackTrace();
}
}

thanks in advance

[jschell]

You can google using the following

java wildcard file search

[Lost User]

You just need to list all files with the .log extension and find the last but one. So since array indices go from 0 to (count_of_entries - 1), the one at offset (count - 2) will be the last but one.

[hm9]

Thanks for the suggestions. I made a start now by listing all the files with the extension .log and it works. since the files are in yyyymmdd.log format, i only want to list the last one - 1. then copy it to another file called logged.log for instance. Could you please help achieve this with the code below?. The code below navigate to the directory and list all files with the extension .log. The printed output is: 20180118.Log 20180117.Log 20180116.Log So I am interested in the second one: 20180117.Log

import java.util.List;
import java.io.File;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.regex.Pattern;

class search
{
public static void main(String[] args) {

String WILD\_CARD = "";
 List fileList = new LinkedList();
   File folder = new File("d:\\\\");
   File\[\] listOfFiles = folder.listFiles();
    if(WILD\_CARD!=null) {  
        Pattern wildCardPattern = Pattern.compile(".\*"+WILD\_CARD+"(.\*)?.log",Pattern.CASE\_INSENSITIVE);
        for(File file: listOfFiles) {
            java.util.regex.Matcher match = wildCardPattern.matcher(file.getName());
            while(match.find()){
                String fileMatch = match.group();
                if(file.getName().equals(fileMatch))  {
                    fileList.add(file); // doesn't work
                }
            }
        }
    }
    else
        fileList = new LinkedList( Arrays.asList(folder.listFiles()));

    for (File f: fileList) System.out.println(f.getName());

}

}

[Lost User]

Obviously it is the opposite of what I suggested, as the list is in descending order.

[hm9]

I just double checked the output printed is in ascending order as shown below: 20180115.LOG 20180116.LOG 20180117.LOG 20180118.LOG

[Lost User]

Then my first suggestion still applies. Is this really so difficult to understand? It seems quite straightforward to me; or maybe I am missing something.

[hm9]

Yes. Just not sure how to do it in the code

[Lost User]

Just count the entries, or convert the list to an array and use the offset value I suggested.

[hm9]

Ok. I tried somehting like this so I can print the last file - 1 it prints the file but with the file path as well

Object item = (((Deque) fileList).getLast()-1);
System.out.println(item);

[Lost User]

So you have a working solution.

[hm9]

Not yet. It prints the path of the file rather than the file It should print:

20180117.LOG

but it is printing

d:\20180117.LOG

I only want the file so I can create a copy of it. Can you try it and see if works for you? may be format issue?

[Lost User]

You just need to use a method to extract just the filename, such as: File (Java Platform SE 7 )[^]. Simple answers like this can usually be found in the documentation.