java.io.IOException: Invalid file path while creating and writing in a File

Question

I am trying to create a file inside a directory but when the code executes it brings back the error 'java.io.IOException: Invalid file path'. And the code does create the directory called 'ServerUploads' but it does not create the file. Below is a code snippet :

   public static String performUploadOperation(byte[] file, String filename)
        throws IOException {
    //creating a directory to store file.
    //creating a directory to store users
    File userDirectory = new File("C:\\ServerUploads");
    //check if directory does not exist.
    if (!userDirectory.exists()) {
        userDirectory.mkdir();
    }


        File crreate = new File(userDirectory + "\\" +  filename);

        if(!crreate.exists())
        crreate.createNewFile();




    try{
    //convert the bytearray retrieved to a file and upload to server folder.
   FileOutputStream fos = new FileOutputStream(crreate);
   System.out.println(fos.toString());
        //write file to directory.
        fos.write(file);
        fos.close();
    }catch(FileNotFoundException e){
        e.printStackTrace();
    }
    sucess = "600 - The file has been successfully uploaded!";
    return sucess;
}

The filename being passed as argument is 'upload.txt' . I am not sure why it is not working. Any help is appreciated. Thanks!. Please see I need the method to return a String not a void as I have to further return it to the client.

Hi, can you try switching \` to /` in your file constructor? also, what is the byte array for? — badperson
– badperson, Commented Mar 16, 2019 at 14:03
I have updated my code with the full method and the forward slash did not work unfortunately. — Gavin Everett
– Gavin Everett, Commented Mar 16, 2019 at 14:19
@GavinEverett Your code is working apart from return sucess; where it should be either String sucess =.... or directly return "600 - The file has been successfully uploaded!" .Can you add your complete exception from console and how you're calling performUploadOperation(..,...) — Vivek
– Vivek, Commented Mar 16, 2019 at 14:44
The createNewFile() call here is a waste of time and space, as are both exists() calls. — user207421
– user207421, Commented Mar 16, 2019 at 22:32

Gavin Everett · Accepted Answer · 2019-03-16 15:58:21Z

2

I have found the solution to the problem. The solution was to add '.trim()' to the filename string. There must have been some white-space when the file came in.

answered Mar 16, 2019 at 15:58

Gavin Everett

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1 Comment

Vivek Over a year ago

Welcome to SO ! Good, as I said your code was working only part we would like to see was how you're calling performUploadOperation(.. , ..) and thus eventually what you're passing in file and filename ! So lesson learnt right? Next time lets add more context/relevance over SO in question and save everyone's time. : )

AshwinK · Accepted Answer · 2019-03-16 14:11:45Z

-1

I tried following code block by just changing return type String to void as nothing was returned. It worked. The folder & file both get created. Here is the code block for same:

public static void performUploadOperation(byte[] file, String filename)
        throws IOException {
    //creating a directory to store file.
    //creating a directory to store users
    File userDirectory = new File("C:\\ServerUploads");
    //check if directory does not exist.
    if (!userDirectory.exists()) {
        userDirectory.mkdir();
    }
    File crreate = new File(userDirectory + "\\" + filename);

    if (!crreate.exists())
        crreate.createNewFile();
}

Calling above function from main:

public static void main(String args[]) throws IOException {
    performUploadOperation("abc".getBytes(),"testfile");
}

answered Mar 16, 2019 at 14:11

AshwinK

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3 Comments

AshwinK Over a year ago

you missed to give variable type. It should be String sucess = not just sucess =. Also the content of file will not get printed in the way you wrote your System.out.println(fos.toString()); It should be replaced with :

ByteArrayOutputStream stream = new ByteArrayOutputStream();             stream.write(file);             System.out.println(new String(stream.toByteArray()));

user207421 Over a year ago

There is nothing here that solves or even identifies the problem.

AshwinK Over a year ago

The issue was java.io.IOException: Invalid file path given by code posted & the answer I posted solves this problem. When I ran this program on my m/c it didn't gave any error.

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