Java adding file contents to array list

Question

Hi i am new to Java working with files. I have got a text file called banking.txt located in C: but when i try put its content into an ArrayList and print it prints out nothing. Is the file path i am using incorrect or is it something different?

import java.util.ArrayList;
import java.util.Scanner;
import java.io.*;

public class FileP {
    public static void main(String[] args) throws FileNotFoundException {
        Scanner read = new Scanner(new File("C:\\banking.txt"));
        ArrayList<String> myList = new ArrayList<String>();
        while(read.hasNextLine()) {
            myList.add(read.nextLine());
        }
        System.out.println(myList);
    }
}

"it prints out nothing": this is hard to believe. Which output do you get exactly? — Henry
– Henry, Commented Jan 25, 2018 at 10:45
Related: Java reading a file into an ArrayList? Although not voting to close as duplicate because your code should be working or throwing an exception (not getting anything in the list should mean the file is empty). — Bernhard Barker
– Bernhard Barker, Commented Jan 25, 2018 at 10:51
You could check whether your file 1) exists and 2) can be read. Check this example : ideone.com/7NckQf — Aaron
– Aaron, Commented Jan 25, 2018 at 10:55
I can reproduce this by trying both File and FileReader in the Scanner constructor trying to read the same system file (on Win 7) - one prints an empty ArrayList, the other prints the file contents. There might be some permissions differences between the two, but I can't tell you what the exact problem is. — Bernhard Barker
– Bernhard Barker, Commented Jan 25, 2018 at 11:15

MadukaJ · Accepted Answer · 2018-01-25 11:10:37Z

2

Try to use InputStream

    import java.io.BufferedReader;
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.util.ArrayList;
    import java.io.InputStream;
    import java.io.InputStreamReader;

    public class FileP {

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

        ArrayList<String> myList = new ArrayList<String>();
        InputStream is = new FileInputStream("C:\\banking.txt");
        BufferedReader buf = new BufferedReader(new InputStreamReader(is));
        String line = buf.readLine();
        StringBuilder sb = new StringBuilder();
        while (line != null)

        {
          myList.add(line);
          line = buf.readLine();
        }

       System.out.println("myList : " + myList);
      }
    }

edited Jan 25, 2018 at 11:10

answered Jan 25, 2018 at 10:55

MadukaJ

7617 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Blue Over a year ago

This works but as others have said the way i did should work too.

Valentin Michalak · Accepted Answer · 2018-01-25 12:51:12Z

1

I guess you need to use this code as the Scanner:

Scanner in = new Scanner(new FileReader("C:\\banking.txt"));

This will read the file as a String and you can add it to Array. Check this post for more: Reading a plain text file in Java

edited Jan 25, 2018 at 12:51

Valentin Michalak

2,1471 gold badge16 silver badges27 bronze badges

answered Jan 25, 2018 at 10:50

DiabloSteve

4212 silver badges13 bronze badges

5 Comments

Bernhard Barker Over a year ago

Why would this fixed the problem? Scanner has a constructor that takes a File.

Blue Over a year ago

I am unsure but with this modification made to my code it is all printed out.

MadukaJ Over a year ago

can you try again with your previous code. because it also have to work.

Blue Over a year ago

I already tried it, i undid all the changes and { } is printed then i switched back again to this code and it prints it correctly i even switched to netbeans and the very same thing.

DiabloSteve Over a year ago

Dukeling. Check these 2 links to know what is the different between "new File()" and "new FileReader()". docs.oracle.com/javase/7/docs/api/java/io/File.html docs.oracle.com/javase/8/docs/api/?java/io/FileReader.html

Stephan Hogenboom · Accepted Answer · 2018-01-25 10:49:24Z

1

I would recommend using the lines method of Java 8:

 Stream<String> content = Files.lines("C:\\banking.txt")
 content.forEach(System.out::println);

answered Jan 25, 2018 at 10:49

Stephan Hogenboom

1,5723 gold badges19 silver badges33 bronze badges

2 Comments

Aaron Over a year ago

Same comment as for CodeMatrix : good suggestion, but no obvious reason why it would fix OP's problem.

DodgyCodeException Over a year ago

Just to be pedantic, the proper way is: try (Stream<String> content = Files.lines("C:\\banking.txt")) { content.forEach(System.out::println); }. This ensures the file gets closed after finishing.

Collectives™ on Stack Overflow

Java adding file contents to array list

3 Answers 3

1 Comment

5 Comments

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

5 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related