checking if file exists in a specific directory

Question

I am trying to check for a specific file in a given directory. I don't want the code but I want to fix the one I have. The only difference in this question, is that I look for files with an extension .MOD.

I have the code ready:-

public static int checkExists(String directory, String file) {
    File dir = new File(directory);
    File[] dir_contents = dir.listFiles();
    String temp = file + ".MOD";
    boolean check = new File(temp).exists();
    System.out.println("Check"+check);  // -->always says false

    for(int i = 0; i<dir_contents.length;i++) {
        if(dir_contents[i].getName() == (file + ".MOD"))
            return Constants.FILE_EXISTS;
    }

    return Constants.FILE_DOES_NOT_EXIST;
}

But for some reasons, it does not work. I don't understand why, can anybody find any bug here?

did you already printed out the tmp value and check if the file really exists? And if so, which env is this (windows or linux) in linux files are case sensitive... — Francisco Spaeth, Jun 27 '12 at 06:42
yes I tried printing the temp value and the file indeed exists in the directory. It is windows OS, but the `file` parameter and the actual name of the file in the directory are case-sensitively same. — gkris, Jun 27 '12 at 06:48

score 53 · Accepted Answer · answered Jun 27 '12 at 06:47

Do you expect temp.MOD file to be in the current directory (the directory from which you run your application), or you want it to be in the "directory" folder? In the latter case, try creating the file this way:

boolean check = new File(directory, temp).exists();

Also check for the file permissions, because it will fail on permission errors as well. Case sensitivily might also be the cause of the issue as Spaeth mentioned.

Akhi · Answer 2 · 2012-06-27T06:56:33.057

5

This is where you have the bug.

String temp = file + ".MOD";

And

if(dir_contents[i].getName() == (file + ".MOD"))

The code boolean check = new File(temp).exists(); will check for the file in the current directory not in the required directory.

    String dirName="/home/demo";
    File dir = new File(dirName);
    File[] dir_contents = dir.listFiles();
    String temp = dirName+"/"+"README" + ".MOD";
    boolean check = new File(temp).exists();
    System.out.println("Check" + check); // -->always says false

    for (int i = 0; i < dir_contents.length; i++) {
        if (dir_contents[i].getName().equals("README" + ".MOD"))
            return Constants.FILE_EXISTS;
            }

    return Constants.FILE_DOES_NOT_EXIST;

edited Jun 27 '12 at 06:56

answered Jun 27 '12 at 06:50

Akhi

2,242
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@gkris and you have to use .equals() in the for loop – Akhi Jun 27 '12 at 06:54
for loop is just another method of checking the same file existence. I had 2 methods to check the same function because none were working. Now I can safely remove the whole for loop. Thanks again. – gkris Jun 27 '12 at 06:57

Kumar Vivek Mitra · Answer 3 · 2012-06-27T07:19:47.370

4

Try this..............

File f = new File("./file_name");
if(f.exists()){
    System.out.println("success");
}
else{
    System.out.println("fail");
}

edited Jun 27 '12 at 07:19

answered Jun 27 '12 at 07:11

Kumar Vivek Mitra

33,294
6
48
75

this wont help because I am not checking for the file in current directory. Anyways I got the answer and accepted it too. Thanks – gkris Jun 27 '12 at 07:17
Well that what i mean in path...ok new File("./file_name"); "." (dot) operator means the current directory – Kumar Vivek Mitra Jun 27 '12 at 07:18
Then simply give the path of the file that is needed – Kumar Vivek Mitra Jun 27 '12 at 08:55

checking if file exists in a specific directory

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