How to read a .csv file into an array list in java?

Question

I have an assignment for college that requires I take data from a .csv file and read it, process it, and print it in three separate methods. The instructions require that I read the data into an array list I have written some code to do so but I'm just not sure if I've done it correctly. Could someone help me understand how exactly I am supposed to read the file into an array list?

my code:

public void readData() throws IOException { 
    int count = 0;
    String file = "bank-Detail.txt";
    try {
        BufferedReader br = new BufferedReader(new FileReader(file));
        String line = "";
        while ((line = br.readLine()) != null) {

            bank.add(line.split(","));

            String[][] v = (String[][]) bank.toArray(new String[bank.size()][12]);

        }
    } catch (FileNotFoundException e) {

    }
}

@Kot the file is 600 or so lines with 12 comma separated parts each — abe
– abe, Commented Feb 11, 2017 at 0:42
You should note an Array of strings and an ArrayList are not the same thing. If the instructions require an ArrayList then you should look into that class. — Alex
– Alex, Commented Feb 11, 2017 at 0:44
Do you need to be able to handle quotation marks correctly? These can be used around a field in CSV, and they need to be used if a field contains a comma. — Dawood ibn Kareem
– Dawood ibn Kareem, Commented Feb 11, 2017 at 1:02

Darshan Mehta · Accepted Answer · 2017-02-11 01:06:57Z

11

You don't need 2D array to store the file content, a list of String[] arrays would do, e.g:

public List<String[]> readData() throws IOException { 
    int count = 0;
    String file = "bank-Detail.txt";
    List<String[]> content = new ArrayList<>();
    try(BufferedReader br = new BufferedReader(new FileReader(file))) {
        String line = "";
        while ((line = br.readLine()) != null) {
            content.add(line.split(","));
        }
    } catch (FileNotFoundException e) {
      //Some error logging
    }
    return content;
}

Also, it's good practice to declare the list locally and return it from the method rather than adding elements into a shared list ('bank') in your case.

edited Feb 11, 2017 at 1:06

answered Feb 11, 2017 at 0:44

Darshan Mehta

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1 Comment

Ali Ben Zarrouk Over a year ago

Nice, but cooler having the separator as a parameter as for CSV, its not always comma.

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