Write CSV in Java (2024)

In this tutorial, we will demonstrate how to write in CSV in Java.

What is a CSV file?
Ans:

CSV- A comma-separated values. A CSV file contains tabular data (numbers and text) in plain-text form.

Why stream is important for reading and writing CSV file in Java?
Ans:

For reading and writing of CSV or text file Stream is very important. Stream is basically a process sequence through which data can either be written in a file or can be read from a file. Stream is a tube from which data bytes are either flow from a program to a destination file or from a destination file to a program.

1. In order to write characters to a file, we need an outputStream.
2. In order to read characters from a file, we need an inputStream.
3. For reading and writing the CSV files, Java has java.io package that has to be imported either for writing or reading. For writing in csv files, FileWriter, BufferedWriter are used.

Two ways in Java to write in CSV File

1. Write using FileWriter
2. Write using BufferedWriter

What is the difference between FileWriter and BufferedWriter in Java?
Ans:

FileWriter writes to files directly and should only be used when the number of writes is minimal. Whereas BufferedWriter is similar to FileWriter, but it writes data into File using an internal buffer. When a result, as the number of write operations increases, the number of real IO operations decreases, and performance improves.

import java.io.FileWriter;

public class FileWriterExample {
    public static void main(String args[]){
         try{
           FileWriter fw = new FileWriter("D:\\testFileWriter.csv");
           fw.write("TechGeekNext - CSV FileWriter Example");
           fw.close();
          }catch(Exception e){
          System.out.println(e);
          }
          System.out.println("File updated successfully!");
     }

import java.io.*;

public class BufferedWriterExample {
public static void main(String[] args) throws Exception {
    FileWriter fileWrt = new FileWriter("D:\\testBufferedWriter.csv");

    BufferedWriter bufferWrt = new BufferedWriter(fileWrt);

    bufferWrt.write("TechGeekNext - CSV BufferedWriter Example");

    bufferWrt.close();

    System.out.println("File updated successfully!");
    }
}