Split comma separated values in java, int and String

Question

I have the following in a text file to import into an ArrayList:

Australia,2

Ghana,4

China,3

Spain,1

My ArrayList is made up of objects from another class, Team which has the fields TeamName and ranking. I can get the following to import the String and int into the team name, but I can't separate the number which is supposed to be the teams ranking:

  public void fileReader()
  {
    try
    {
        String filename = "teams.txt";
        FileReader inputFile = new FileReader(filename);
        Scanner parser = new Scanner(inputFile);

        for (Team teams : teams)
        {                 
            teams.setTeamName(parser.next());
            teams.setRanking(parser.next()); //this doesn't work
        }
    }

    catch (IOException e)
    {
        System.out.println("Cannot find file");
    }

}

I'm guessing I have to use a split somewhere along the line, or convert a String to an integer??

Answer 1

Scanner.next() read the next token from input stream, and give String .

If you want to read the next integer, you should use nextInt() instead:

teams.setRanking(parser.nextInt());

Edit

You got InputMismatchException because by default, Scanner use java whitespace as delimeter.

WHITESPACE_PATTERN = Pattern.compile("\\\\p{javaWhitespace}+")

In your case, the delimeter are comma , and new line \\n so you should config the delimeter for your scanner:

Scanner parser = new Scanner(inputFile);
s.useDelimiter(",|\\n")

Another work around is to read the whole line and parse your line:

String line = parse.nextLine();
String[] parts = line.split(",");
team.setTeamName(parts[0]);
team.setRanking(Integer.parse(parts[1]));

You can choose one of the two solutions above

Answer 2

Check out opencsv. It's 2018 and you shouldn't have to parse a text file yourself :).

Answer 3

By default scanner will use white space as delimiter

Override this by calling useDelimiter method in your case parser.useDelimiter(',');

Then for converting ranking string to int you parser.nextInt()

Answer 4

You can code something like below to suite your purpose. You have two tokens in your use case ie comma (,) and new line (\\n). As a result, next() can't be used in a straight forward way.

I am going over each line, then tokenizing each line on comma and finally getting subsequent tokens.

try
    {
        String filename = "teams.txt";
        FileReader inputFile = new FileReader(filename);
        Scanner parser = new Scanner(inputFile);

        for (Team teams : teams)
        {   
            String[] splitLine = sc.nextLine().split(","); // comma delimited array

            teams.setTeamName(splitLine[0]);
            teams.setRanking(splitLine[1]); 
        }
    }