Working With CSV Files in Java Using Apache Commons CSV
Need to read CSV files quickly and efficiently in your Java projects? Let's get Apache Commons CSV added to your setup and see it in action.
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Join For FreeThe Apache Commons CSV library is a Java library that can be used to read and write CSV files in a very simple and easy way. Another advantage is that this Java library is open source and freely available to use.
First, we need to add the library to your project.
To add it a Maven dependency, you just need to add this dependency to your pom.xml file:
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-csv</artifactId>
<version>1.5</version>
</dependency>
Or, to add it as a Gradle dependency, you can just add this to your dependencies within the build.gradle file:
compile "org.apache.commons:commons-csv:1.5"
Let's start by generating a simple CSV file — student.csv — in the following program.
Our program to generate a simple CSV file:
import java.io.IOException;
import java.io.Writer;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.Arrays;
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVPrinter;
public class BasicCsvWriter {
public static void main(String[] args) {
try {
//We have to create the CSVPrinter class object
Writer writer = Files.newBufferedWriter(Paths.get("student.csv"));
CSVPrinter csvPrinter = new CSVPrinter(writer, CSVFormat.DEFAULT.withHeader("Student Name", "Fees"));
//Writing records in the generated CSV file
csvPrinter.printRecord("Akshay Sharma", 1000);
csvPrinter.printRecord("Rahul Gupta", 2000);
csvPrinter.printRecord("Jay Karn", 3000);
//Writing records in the form of a list
csvPrinter.printRecord(Arrays.asList("Dev Bhatia", 4000));
csvPrinter.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
}
This program generates the student.csv file with the content as follows:
Student Name, Fees
Akshay Sharma,1000
Rahul Gupta,2000
Jay Karn,3000
Dev Bhatia,4000
Let's now read the content of the generated CSV file using the following program:
import java.io.BufferedReader;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import org.apache.commons.csv.CSVFormat;
import org.apache.commons.csv.CSVParser;
import org.apache.commons.csv.CSVRecord;
public class BasicCsvReader {
public static void main(String[] args) throws IOException {
BufferedReader reader = Files.newBufferedReader(Paths.get("student.csv"));
CSVParser csvParser = new CSVParser(reader, CSVFormat.DEFAULT.withHeader("Student Name", "Fees").withIgnoreHeaderCase().withTrim());
for (CSVRecord csvRecord: csvParser) {
// Accessing Values by Column Index
String name = csvRecord.get(0);
//Accessing the values by column header name
String fees = csvRecord.get("fees");
//Printing the record
System.out.println("Record Number - " + csvRecord.getRecordNumber());
System.out.println("Name : " + name);
System.out.println("Fees : " + fees);
System.out.println("\n\n");
}
}
}
The output will be generated on the console as follows:
Record Number - 1
Name : Akshay Sharma
Fees : 1000
Record Number - 2
Name : Rahul Gupta
Fees : 2000
Record Number - 3
Name : Jay Karn
Fees : 3000
Record Number - 4
Name : Dev Bhatia
Fees : 4000
Published at DZone with permission of Akshay Sharma. See the original article here.
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