FileWriter not writing to file

Question

i have written a program that is supposed to get a value from an existing file, add one to that value, delete the file, create a new instance of the file, and write the new value to the new instance of the file.

public static void main(String[] args) throws InterruptedException, IOException {

    //initialize newFile and writer
    File newFile = new File("C:\\Users\\boung\\Desktop\\python\\daysSince.txt");
    FileWriter writer = new FileWriter("C:\\Users\\boung\\Desktop\\python\\daysSince.txt", true);

    //if newFile doesn't exist or of newFile doesn't contain any content, create newFile and write "1" to newFile
    if(newFile.length() == 0) {

        System.out.println("empty");
        writer.write("1");
        writer.write("\r\n");
        writer.close();

    } else {

        //get contents of newFile
        StringBuilder contentBuilder01 = new StringBuilder();                       
        try (Stream<String> stream = Files.lines( Paths.get("C:\\Users\\boung\\Desktop\\python\\daysSince.txt"), StandardCharsets.UTF_8)) {

                stream.forEach(s -> contentBuilder01.append(s).append("\n"));

            } catch (IOException e) {

                e.printStackTrace();

            }

        //convert content to integer
        String content = contentBuilder01.toString();
        content = content.replaceAll("\\D+", "");
        int value = Integer.parseInt(content);
        System.out.println(value);

        //add 1 to the value that was returned from getting the contents of newFile and assign it to newValue
        int newValue = value + 1;

        //delete newFile
        newFile.delete();

        //create new instance of newFile to prepare for next execution
        if(newFile.length() == 0) { 
        newFile = new File("C:\\Users\\boung\\Desktop\\python\\daysSince.txt");
        }

        FileWriter writer1 = new FileWriter("C:\\Users\\boung\\Desktop\\python\\daysSince.txt", true);          

        //write newValue to new instance of newFile
        writer1.write(newValue);
        System.out.println("printed " + newValue);
        writer1.write("\r\n");
        writer1.close();
    }



}       

the problem is occurring in this area

        writer1.write(newValue);
        System.out.println("printed " + newValue);
        writer1.write("\r\n");
        writer1.close();

assuming that newFile doesnt exist, after running the program twice the expected output would look like this

2

but this is the output i am getting

1

but here the program has no problem writing 1 to the file if the file is empty or does not exist

    System.out.println("empty");
    writer.write("1");
    writer.write("\r\n");
    writer.close();

i assume i have made a mistake with the logic of the program, can anyone help?

Answer 1

I believe your program has two problems:

1. newFile.delete(); does nothing because writer is still open. You need to first close writer by doing writer.close(); .
2. writer1.write(newValue); writes newValue as an int . That means it's literally taking all the binary digits that represent that number and just writing them straight to the file. Instead, you want to write newValue as a String , which will produce that number in text so you can read it. So you want to use writer1.write(Integer.toString(newValue)); instead.

Answer 2

The newFile.delete(); is unnecessary, you don't need to delete the file to write to it again. The following code sample works for me and outputs correctly.

    StringBuilder contentBuilder01 = new StringBuilder();
    try (Stream<String> stream = Files.lines( Paths.get(fileName), StandardCharsets.UTF_8)) {
        stream.forEach(s -> contentBuilder01.append(s).append("\n"));
    } catch (IOException e) {
        e.printStackTrace();
    }
    FileWriter writer = new FileWriter(fileName);
    writer.write(Integer.toString(Integer.parseInt(contentBuilder01.toString().trim()) + 1));
    writer.close();