Java - Read many txt files on a folder and process them

Question

I followed this question:

Now in my case i have 720 files named in this way: "dom 24 mar 2013_00.50.35_128.txt", every file has a different date and time. In testing phase i used Scanner, with a specific txt file, to do some operations on it:

Scanner s = new Scanner(new File("stuff.txt"));

My question is:

How can i reuse scanner and read all 720 files without having to set the precise name on scanner?

Thanks

see here http://stackoverflow.com/questions/189094/how-to-scan-a-folder-in-java — sotix, Jul 18 '13 at 16:38
Can you just read all the files in the directory, or you have more files that you don't want to be read with different naming schemes in the directory as well? — Kevin DiTraglia, Jul 18 '13 at 16:38

arshajii · Accepted Answer · 2013-07-18T16:46:39.720

16

Assuming you have all the files in one place:

File dir = new File("path/to/files/");

for (File file : dir.listFiles()) {
    Scanner s = new Scanner(file);
    ...
    s.close();
}

Note that if you have any files that you don't want to include, you can give listFiles() a FileFilter argument to filter them out.

edited Jul 18 '13 at 16:46

answered Jul 18 '13 at 16:38

arshajii

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Yes, all the files are in the same folder. – alessandrob Jul 18 '13 at 16:40
2

Damn, you just beat me to it :) +1 for beating me to the answer – nullByteMe Jul 18 '13 at 16:40
how can we read the multiple files in case the files are located in different directories ? – Suleman khan Jan 21 '16 at 20:46

nullByteMe · Answer 2 · 2013-07-18T17:13:49.427

8

Yes, create your file object by pointing it to a directory and then list the files of that directory.

File dir = new File("Dir/ToYour/Files");

if(dir.isDir()) {
   for(File file : dir.listFiles()) {
      if(file.isFile()) {
         //do stuff on a file
      }
   }
} else {
   //do stuff on a file
}

edited Jul 18 '13 at 17:13

answered Jul 18 '13 at 16:39

nullByteMe

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score 3 · Answer 3 · answered Jul 18 '13 at 16:51

You can try this in this way

 File folder = new File("D:\\DestFile");
 File[] listOfFiles = folder.listFiles();

 for (File file : listOfFiles) {
 if (file.isFile()&&(file.getName().substring(file.getName().lastIndexOf('.')+1).equals("txt"))) {
   // Scanner 
  }
 }

score 1 · Answer 4 · answered Jul 18 '13 at 16:41

1

    File file = new File(folderNameFromWhereToRead);

    if(file!=null && file.exists()){
        File[] listOfFiles = file.listFiles();

        if(listOfFiles!=null){

            for (int i = 0; i < listOfFiles.length; i++) {
                if (listOfFiles[i].isFile()) {
                      // DO work
                }
            }
        }
    }

answered Jul 18 '13 at 16:41

Jayesh

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I'm no expert, but I think your `if(listOfFiles!=null)` is unnecessary. You just created the `listOfFiles` so how can it be null? – nullByteMe Jul 18 '13 at 16:55
Ughh.. same with your `if(file!=null)`... you're testing whether an object reference exist which you just made prior to the test! – nullByteMe Jul 18 '13 at 17:02
Null check on `lisOfFiles` is okay (it could happen if the path exists but is a file) but on the `file` isn't required. +1 for the `isFile()` check anyway. – Ravi K Thapliyal Jul 18 '13 at 17:07
@RaviThapliyal good call, I didn't think about that with `listOfFiles` because I would have written my code to first check if `file` is a directory and then processed `listFiles()`. – nullByteMe Jul 18 '13 at 17:11

Java - Read many txt files on a folder and process them

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