How to use PrintWriter and File classes in Java?

SPARK picture SPARK · Jul 16, 2012 · Viewed 391.6k times · Source

I am trying to understand PrintWriter for a small program I'm making, and I cant seem to get java to make the file and then write on it. When I execute the program below it gives me a Filenotfoundexeption error on line 9. It also fails to make the file in the directory that I specified. I am new to this so please try and keep the answers simple. I am using Eclipse.

import java.io.PrintWriter;
import java.io.File;

public class Testing {

  public static void main(String[] args) {

    File file = new File ("C:/Users/Me/Desktop/directory/file.txt");
    PrintWriter printWriter = new PrintWriter ("file.txt");
    printWriter.println ("hello");
    printWriter.close ();       
  }
}

Answer

Jack picture Jack · Jul 16, 2012

If the directory doesn't exist you need to create it. Java won't create it by itself since the File class is just a link to an entity that can also not exist at all.

As you stated the error is that the file cannot be created. If you read the documentation of PrintWriter constructor you can see

FileNotFoundException - If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file

You should try creating a path for the folder it contains before:

File file = new File("C:/Users/Me/Desktop/directory/file.txt");
file.getParentFile().mkdirs();

PrintWriter printWriter = new PrintWriter(file);