Question

I want to read a PSV file using java. Records in my PSV file has 4 columns. I want to read and output only the 3 and 4th column. What is the best way to do this.
Here is what I have:

BufferedReader PSVFile = new BufferedReader(new FileReader(fileName));
String dataRow = PSVFile.readLine();
while (dataRow != null)
{
    String[] dataArray = dataRow.split("\n");
    for (String item:dataArray) 
    {
        String[] elements = item.split("|");
        System.out.println(item);
    }
    System.out.println();
    dataRow = PSVFile.readLine();
}
PSVFile.close();
System.out.println();

Based on @AljoshaBre suggestion Iam using CSVReader, doing this:

reader = new CSVReader(new FileReader(fileName),'|');
String [] nextLine;
while ((nextLine = reader.readNext()) != null) 
{
 System.out.println( nextLine[3] + nextLine[4]);
}

I am getting the desired output but then get an error:
Exception in thread “main” java.lang.ArrayIndexOutOfBoundsException: 2
at Read_PSV.main(Read_PSV.java:20)
Line 20 is System.out.println( nextLine[3] + nextLine[4]);

Answer 1

OpenCSV is my weapon of choice.

This snippet will get you third and forth columns:

try {
    //last parameter tells it which line (row) to consider as the first one
    CSVReader reader = new CSVReader(new FileReader("res/test.csv"), '|', '\0', 1);
    String[] row;

    List<String> columnThree    = new ArrayList<String>();
    List<String> columnFour     = new ArrayList<String>();

    while((row = reader.readNext()) != null) {
        columnThree.add(row[2]);
        columnFour.add(row[3]);
    }
    reader.close();
} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
}

It will print

Nikola
Nenad
Ljubinka
Gordana

for this input:

test.psv

Name|Surname|Father|Mother
Aleksandar|Milic|Nikola|Ljubinka
Nebojsa|Jakovljevic|Nenad|Gordana