Java File.renamTo not working

Question

I have made the code which renames all the jpg files in a directory from 1 to n (number of files).. if there were let say 50 jpg files that after running the program all the files are renamed to 1.jpg ,2.jpg and so on till 50.jpg But i am facing the problem if I manually rename the file let say 50.jpg to aaa.jpg then again running the program doesn't rename that file I have wasted one day to resove that issue Kindly help me Code:

public class Renaming {
    private static String path;             // string for storing the path
    public static void main(String[] args) {

        FileReader fileReader = null;           // filereader for opening the file
    BufferedReader bufferedReader = null;   // buffered reader for buffering the data of file
        try{
            fileReader = new FileReader("input.txt");   // making the filereader object and paasing the file name
            bufferedReader = new BufferedReader(fileReader); //making the buffered Reader object
            path=bufferedReader.readLine();
            fileReader.close();
            bufferedReader.close();
        }
        catch (FileNotFoundException e) {           // Exception when file is not found
            e.printStackTrace();
        } 
        catch (IOException e) {                     // IOException
            e.printStackTrace();
        }
        finally {

             File directory=new File(path);

        File[] files= directory.listFiles();        // Storing the all the files in Array

        int file_counter=1;
           for(int file_no=0;file_no<files.length;file_no++){
               String Extension=getFileExtension(files[file_no]);   //getting the filw extension
               if (files[file_no].isFile() && (Extension .equals("jpg")|| Extension.equals("JPG"))){            // checking that if file is of jpg type then apply renaming         // checking thaat if it is file

                File new_file = new File(path+"\\"+files[file_no].getName()); //making the new file

                new_file.renameTo(new File(path+"\\"+String.valueOf(file_no+1)+".jpg"));   //Renaming the file
               System.out.println(new_file.toString());
                file_counter++;             // incrementing the file counter
            }

        }

        }


}

private static String getFileExtension(File file) {     //utility function for getting the file extension 
    String name = file.getName();
    try {
        return name.substring(name.lastIndexOf(".") + 1);   // gettingf the extension name after . 
    } catch (Exception e) {
        return "";
    }
}`

The correct tool to solve this is a debugger - step through your code and observe the values of variables and what your code does. — UnholySheep, Jul 17 '17 at 11:59
If your debugger doesn't work then you need to fix that first. A debugger is a programmer's most important tool. If by *"didn't work"* you mean you weren't able to figure out the solution then you should at least be able to tell exactly which call doesn't do what you want it to (and whether the values are correct at that point) — UnholySheep, Jul 17 '17 at 14:23

score 0 · Accepted Answer · answered Jul 18 '17 at 20:42

first of all, you should use the path separator / . It's work on Windows, Linux and Mac OS. This is my version of your problem to rename all files into a folder provide. Hope this will help you. I use last JDK version to speed up and reduce the code.

public class App {

    private String path = null;
    public static int index = 1;

    public App(String path){
        if (Files.isDirectory(Paths.get( path ))) {
            this.path = path;
        }
    }

    public void rename() throws IOException{
        if ( this.path != null){
            Files.list(Paths.get( this.path ))
            .forEach( f -> 
            {
                String fileName = f.getFileName().toString();
                String extension = fileName.replaceAll("^.*\\.([^.]+)$", "$1");             

                try {
                    Files.move( f ,Paths.get( this.path + "/" +   App.index + "." + extension));
                    App.index++;
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }           
            );
        }
    }

    public static void main(String[] args) throws IOException {
        App app = new App("c:/Temp/");
        app.rename();
    }
}

Java File.renamTo not working

1 Answers1