Using OpenCSV with Try-With-Resources for Cleaner Code

When working with CSV files in Java, one of the most common challenges developers face is resource management. Forgetting to close file readers or writers can cause memory leaks, file locks, and unwanted bugs. Fortunately, modern Java (from version 7 onwards) introduced a powerful feature called try-with-resources.

In this tutorial, we will explore how to use OpenCSV with try-with-resources to write cleaner, safer, and more maintainable code. By combining the simplicity of OpenCSV with this modern Java feature, you can focus on your logic instead of worrying about closing streams.

Using OpenCSV with Try-With-Resources for Cleaner Code

Why Use Try-With-Resources with OpenCSV?

Here are the main benefits:

Automatic resource closing – No need for manual finally blocks.
Cleaner code – Reduces boilerplate and improves readability.
Error safety – Ensures resources are closed even if an exception occurs.
Best practice – Recommended in production-grade applications for file handling.

Maven Dependency for OpenCSV

Make sure you add OpenCSV in your pom.xml:

<groupId>com.opencsv</groupId>

<artifactId>opencsv</artifactId>

</dependency>

Example 1: Reading a CSV File with Try-With-Resources

package com.kscodes.opencsv;

import com.opencsv.CSVReader;

import java.io.FileReader;

import java.io.IOException;

public class ReadCSVWithTWR {

public static void main(String[] args) {

String filePath = "data.csv";

try (CSVReader reader = new CSVReader(new FileReader(filePath))) {

String[] line;

while ((line = reader.readNext()) != null) {

System.out.println("Name: " + line[0] + ", Age: " + line[1]);

}

} catch (IOException e) {

e.printStackTrace();

}

👉 Notice that there is no need to call reader.close() explicitly. The try-with-resources block takes care of it automatically.

Example 2: Writing to a CSV File with Try-With-Resources

package com.kscodes.opencsv;

import com.opencsv.CSVWriter;

import java.io.FileWriter;

import java.io.IOException;

public class WriteCSVWithTWR {

public static void main(String[] args) {

String filePath = "output.csv";

try (CSVWriter writer = new CSVWriter(new FileWriter(filePath))) {

String[] header = { "Name", "Age" };

writer.writeNext(header);

String[] row1 = { "Alice", "24" };

String[] row2 = { "Bob", "30" };

writer.writeNext(row1);

writer.writeNext(row2);

System.out.println("CSV file written successfully.");

} catch (IOException e) {

e.printStackTrace();

}

Here too, the writer is closed automatically.

Best Practices

Always use try-with-resources when working with file I/O.
Combine OpenCSV with logging frameworks (like SLF4J) instead of printStackTrace for real-world projects.
Validate file paths before reading/writing.

Conclusion

By using OpenCSV with try-with-resources, you get cleaner, safer, and more professional code. This approach not only prevents resource leaks but also makes your application easier to maintain. Whether you are building a small utility or a large enterprise application, adopting this practice is a must.

For further reading: