Java create multiple new files

Question

I read this question here How to create a file in a directory in java?

I have a method that creates a QR Code. The method is called several times, depends on user input.

This is a code snippet:

String filePath = "/Users/Test/qrCODE.png";
int size = 250;
//tbd
String fileType = "png";
File myFile = new File(filePath);

The problem: If the user types "2" then this method will be triggered twice. As a result, the first qrCODE.png file will be replaced with the second qrCODE.png, so the first one is lost.

How can I generate more than one qr code with different names, like qrCODE.png and qrCODE(2).png

My idea:

if (!myFile.exists()) {
    try {
        myFile.createNewFile();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Any tips?

EDIT: I solved it by using a for loop and incrementing the number in the filename in every loop step.

Why not testing the presence of the file before saving it, and if it exists recursively try with filename+(2) ? — Romano, Jan 31 '19 at 14:24
`File.createTempFile("qrCODE", ".png", new File("/Users/Test"));` — Lothar, Jan 31 '19 at 14:27
Maybe use the timestamp in the file name: `System.currentMillis()` or use a `UUID` — Lino, Jan 31 '19 at 14:36

xxxvodnikxxx · Answer 1 · 2019-02-11T13:07:01.183

You can create more files eg. like follows

int totalCount = 0; //userinput

String filePath = "/Users/Test/";
String fileName= "qrCODE";
String fileType = "png";

for(int counter = 0; counter < totalCount; counter++){
    int size = 250;
    //tbd
    File myFile = new File(filePath+fileName+counter+"."+fileType);
    /*
       will result into files qrCODE0.png, qrCODE1.png, etc.. 
        created at the given location
    */
}

Btw to add check if file exists is also good point.

{...}
 if(!myFile.exists()){
    //file creation
    myFile.createNewFile()
 }else{
   //file already exists
 } 
{...}

score 2 · Answer 2 · answered Jan 31 '19 at 14:35

You can check /Users/Test direcroty before create file.

String dir = "/Users/Test";
String pngFileName = "qrCode";

long count = Files.list(Paths.get(dir))      // get all files from dir
    .filter(path -> path.getFileName().toString().startsWith(pngFileName))   // check how many starts with "qrCode"
    .count();

pngFileName = pngFileName + "(" + count + ")";

S.Tushinov · Accepted Answer · 2019-01-31T16:14:47.097

Your idea of solving the problem is a good one. My advice is to break up the filePath variable into a few variables in order to manipulate the file name easier. You can then introduce a fileCounter variable that will store the number of files created and use that variable to manipulate the name of the file.

int fileCounter = 1;
String basePath = "/Users/Test/";
String fileName = "qrCODE";
String fileType = ".png";

String filePath = basePath + fileName + fileType;
File myFile = new File(filePath);

You can then check if the file exists and if it does you just give a new value to the filePath variable and then create the new file

if(myFile.exists()){
    filePath = basePath + fileName + "(" + ++fileCounter + ")" + fileType;
    myFile = new File(filePath);
}
createFile(myFile);

And you're done!

Java create multiple new files

3 Answers3