How to read and write a CSV file using core java?

Hello Buddies.

CSV: A CSV is a comma separated values file which allows data to be saved in a table structured format

Let's try to read a CSV file using java, filter out the required rows and create a new CSV per our own requirements.

Input - Provided as a path for the file having below details -

ID	NAME	AGE	GENDER	OCCUPATION	ADDRESS
1	ABC	22	M	SE	IN
2	DEF	32	F	SE	US
3	ABC	12	M	SE	UK
4	DEF	42	F	SE	IN
5	ABC	52	M	SE	US
6	DEF	53	F	SE	UK
7	ABC	60	M	SE	IN
8	DEF	67	F	SE	US
9	ABC	74	M	SE	UK
10	DEF	81	F	SE	IN
11	ABC	88	M	SE	US

We will filter out the people living in India and will have a new CSV only for those people.

Here's a code snippet -

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class CSVReader {

 private static String mainPath = "C:\\\\Users\\\\namit.sharma\\\\Downloads\\\\";

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

  FileReader fileReader = new FileReader(new File(mainPath + "sampleExcel1.csv"));

  BufferedReader bufferedReader = new BufferedReader(fileReader);

  String string;
  do {
   string = bufferedReader.readLine();
   if (null != string) {
    System.out.println(string);
    filterForIndians(string);
   }
  } while (null != string);

  bufferedReader.close();

 }

 private static void filterForIndians(String string) throws IOException {
  File file = new File(mainPath + "fileredCsv.csv");
  if (file.exists()) {
   file.delete();
  }
  FileWriter fileWriter = new FileWriter(new File(mainPath + "fileredCsv.csv"),true);
  if ("IN".equals(string.split(",")[5])) {
   BufferedWriter bufferedWriter = new BufferedWriter(fileWriter);
   bufferedWriter.write(string+"\n");
   bufferedWriter.close();
  }
 }

}

Now we can check the generated csv. It will have the desired rows -

1	ABC	22	M	SE	IN
4	DEF	42	F	SE	IN
7	ABC	60	M	SE	IN
10	DEF	81	F	SE	IN