Java Scanner（System.in）在用户输入后不打开文件

Question

Hello there I am facing an issue which I cannot find a solution. I am asking the user to input the name of a file but the output i get is always ''unable to open file''. Any advice would be much appreciated.

    Scanner reader = new Scanner(System.in); 
    System.out.println("Enter the name of textfile to be read ( add .txt): ");

    String fileName = reader.next();
    String line = null;
    BufferedReader bufferedReader =   new BufferedReader(fileReader);

    while((line = bufferedReader.readLine()) != null) {
        System.out.println(line); 

        catch(FileNotFoundException ex) {
        System.out.println(
            "Unable to open file '" + 
            fileName + "'");                
       }

        catch(IOException ex) {
        System.out.println(
            "Error reading file '" 
            + fileName + "'");                  
        // Or we could just do this: 
        // ex.printStackTrace();
    }
    }

The FileNotFoundException is always executed but why?

PS if I change the path to a specific location such as "C:\\etc" it reads the file.

Answer 1

If you only give the file name and not the path, Java doesn't know where to look. If you are certain that the file will be in the project directory, just prepend C:/etc to the user input.

Answer 2

If you don't specify the absolute file path, ie, C:/dir/... , java will look in the same directory as the project root (the same directory as your src and bin folders). If the file is there, it will find it with just the file name, or if you make a directory in that folder, you would need that directory in the path. The same is true if you have an executable JAR, it will look in the same directory that the JAR is located.