Reading a column from CSV file using JAVA [duplicate]

Answer 1

If you are using Java 7+, you may want to use NIO.2, e.g.:

❍ Code:

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

    File file = new File("test.csv");

    List<String> lines = Files.readAllLines(file.toPath(), 
            StandardCharsets.UTF_8);

    for (String line : lines) {
        String[] array = line.split(",", -1);
        System.out.println(array[0]);
    }

}

❍ Output:

a
1RW
1RW
1RW
1RW
1RW
1RW
1R1W
1R1W
1R1W

Answer 2

You are not changing the value of line. It should be something like this.

import java.io.BufferedReader;
import java.io.FileReader;

public class InsertValuesIntoTestDb {

  @SuppressWarnings("rawtypes")
  public static void main(String[] args) throws Exception {
      String splitBy = ",";
      BufferedReader br = new BufferedReader(new FileReader("test.csv"));
      while((line = br.readLine()) != null){
           String[] b = line.split(splitBy);
           System.out.println(b[0]);
      }
      br.close();

  }
}

readLine returns each line and only returns null when there is nothing left. The above code sets line and then checks if it is null.

Answer 3

Splitting by comma doesn't work all the time for instance if you have csv file like

"Name" , "Job" , "Address"
"Pratiyush, Singh" , "Teacher" , "Berlin, Germany"

So, I would recommend using the Apache Commons CSV API:

    Reader in = new FileReader("input1.csv");
    Iterable<CSVRecord> records = CSVFormat.EXCEL.parse(in);
    for (CSVRecord record : records) {
      System.out.println(record.get(0));
    }

Answer 4

Read the input continuously within the loop so that the variable line is assigned a value other than the initial value

while ((line = br.readLine()) !=null) {
  ...
}

Aside: This problem has already been solved using CSV libraries such as OpenCSV. Here are examples for reading and writing CSV files