Change files names in parent and child directories

Question

I am a beginner in Java trying to work with Files and Directories. I wanted to create a program where I could change file names automatically while searching through all the child directories for file names that are not valid. I am actually trying to load a huge amount of files on to a server but the server settings do not allow file names containing special characters. To start with I was able to write the code where if I pass the path to a directory it renames all the files with invalid names in that directory:

public class reNaming {

public static String baseLoc = "C:/Users/Developer/Desktop/.../Data Cleanup";

public static void main(String[] args) {

    //LinkedList<File> fileList = new LinkedList<File>();
    File obj = new File(baseLoc);
    int count = 0;

    for (File file: obj.listFiles())
    {

        String origName = file.getName();

        if (origName.contains("&")  || origName.contains("#") || origName.contains("@"))
        {
            System.out.println("Original name: "+origName);
            origName = origName.replaceAll("&", "_and_");
            origName = origName.replaceAll("@", "_at_");
            String newName = origName.replaceAll("#", "_");
            System.out.println("New Name: "+newName);
            String newLoc = baseLoc+"/"+newName;
            File newFile = new File(newLoc);
            System.out.println(file.renameTo(newFile));
            count++;
        }

    }
}

}

Now I want to do the same but only this time I want all the files to be reNamed even in the child directories. Can somebody please guide me how I can achieve that?

you may have to use recursion - See http://stackoverflow.com/questions/189094/how-to-scan-a-folder-in-java — senseiwu, Oct 30 '13 at 15:19

Lan · Accepted Answer · 2013-10-30T15:39:14.807

Recursion is your friend

/**Removes 'invalid' characters (&,#,@) from pathnames in the given folder, and subfolders, and returns the number of files renamed*/
public int renameDirectory(File base){
    //LinkedList<File> fileList = new LinkedList<File>();

    int count=0;//count the renamed files in this directory + its sub. You wanted to do this?

    //Process each file in this folder.
    for (File file: base.listFiles()){

        String origName = file.getName();
        File resultFile=file;

        if (origName.contains("&")  || origName.contains("#") || origName.contains("@")){
            //I would replace the if statement with origName.matches(".*[&#@].*") or similar, shorter but more error prone.
            System.out.println("Original name: "+origName);
            origName = origName.replaceAll("&", "_and_");
            origName = origName.replaceAll("@", "_at_");
            String newName = origName.replaceAll("#", "_");
            System.out.println("New Name: "+newName);
            String newLoc = baseLoc+File.separator+newName;//having "/" hardcoded is not cross-platform.
            File newFile = new File(newLoc);
            System.out.println(file.renameTo(newFile));
            count++;
            resultFile=newFile;//not sure if you could do file=newFile, tired
        }

        //if this 'file' in the base folder is a directory, process the directory 
        if(resultFile.isDirectory()){//or similar function
            count+=renameDirectory(resultFile);
        }
    }
    return count; 
}

Thanks. It helped me understanding the file functions. However, I am unable to pass baseLoc from main() and modify that to new location in the recursive function. — user1827582, Oct 30 '13 at 17:45
figured it out. Sorry was getting confused over a trivial issue. Thanks for your help. :) — user1827582, Oct 30 '13 at 18:52

MadConan · Answer 2 · 2013-10-30T15:23:05.693

Move the code you have to a utility method (e.g. public void renameAll(File f){}). Have a condition that checks if the file is a directory and recursively call your method with it's contents. After that do what you are currently doing.

public void renameAll(File[] files){

    for(File f: files){
        if(f.isDirectory){
           renameAll(f.listFiles());
        }
        rename(f);

    }

}

public void rename(File f){ }

Change files names in parent and child directories

2 Answers2