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Discover how to easily read a specific column (like age) from a CSV file using Java without any external libraries. Follow our step-by-step guide for a quick solution!
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How to Read a Specific Column from a CSV File in Java: A Simple Implementation

Working with CSV files is a common task for developers, especially when handling large amounts of data. One frequent requirement is to read a specific column from a CSV file. In this guide, we’ll walk through how to read a specific column, such as age, from a CSV file using Java without relying on any external libraries like OpenCSV.

The Problem

Imagine you have a CSV file that contains various pieces of information, as shown below:

agedatanumbers111343423433444223232332In this example, you want to extract only the values from the age column, while ignoring the header row. So, how can you achieve this in Java?

The Solution

Overview

We can use Java's built-in Files and Path functionalities to read the CSV file. Our approach will be as follows:

Read all lines from the CSV file.

Skip the header row to avoid including it in our results.

Split each line to access the specific column (in this case, age).

Collect the results into an ArrayList.

Step-by-Step Code Explanation

Here’s a simple implementation using Java streams:

[[See Video to Reveal this Text or Code Snippet]]

Let’s break down each part of the code:

1. Reading Lines

The Files.readAllLines() method retrieves all lines from your specified CSV file. Provide the correct file path to get started.

2. Skipping the Header

We use .skip(1) to skip the first entry of the result, which is the header row. This ensures that we are only working with the actual data.

3. Mapping to Specific Column

The expression .map(line -> line.split(";")[0]) splits each line based on the delimiter (;) and retrieves the value of the first column (i.e., age). Adjust the index in split() if your target column changes.

4. Collecting into an ArrayList

Finally, .collect(Collectors.toList()) gathers all the ages into a list. You can assign this result to an ArrayList<String>, for example.

Complete Example

Putting it all together, here’s a complete Java program:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Reading a specific column from a CSV file in Java can be accomplished quite easily with the right tools from the built-in Java library. This approach is efficient, clean, and straightforward—perfect for developers who wish to avoid external dependencies.

Now you can confidently extract any column you need from your CSV file! Try this method in your projects, and enhance your data handling skills. Happy coding!