Java Split CSV String to List

To convert comma separated string to list in java, you can use below methods.

Comma-separated String to List Using Regex

You can use regular expression "\\s*,\\s*" to match comma into CSV list and then use String.split() method.

import java.util.Arrays;
import java.util.List;

public class CSVSplitExample {

	public static void main(String[] args) {

		String alpha = "how, to, do, in, java";

		//Remove whitespace and split by comma
		List<String> result = Arrays.asList(alpha.split("\\s*,\\s*"));

		System.out.println(result);
	}

}

Output: [how, to, do, in, java]

This resulting List is a fixed-size List backed by the array. It means you cannot add or remove elements from this list. If you want a modifiable list then use next approach.

Convert CSV to Modifiable List

import java.util.Arrays;
import java.util.List;

public class CSVSplitExample2 {

	public static void main(String[] args) {

		String alpha = "how, to, do, in, java";

		//Typecast to ArrayList
		List<String> result = new ArrayList<String>( Arrays.asList(alpha.split("\\s*,\\s*")) );

		System.out.println(result);

		result.add("com");

		System.out.println(result);
	}

}

Output: [how, to, do, in, java]
[how, to, do, in, java, com]

Convert List of Strings to CSV

If you want to convert list to comma-separated string, then use String.join() method provided by java 8.

import java.util.Arrays;
import java.util.List;

public class TestCustomSerialization 
{
	public static void main(String[] args) {
		 
		List<String> list = Arrays.asList("how", "to", "do", "in", "java");

		String result = String.join("-", list);
		System.out.println(result);
		
		String result2 = String.join("", list);
		System.out.println(result2);
    }
}

Output: how-to-do-in-java
howtodoinjava

I hope above examples will help you while converting from comma-separated string to list of string and vice-versa.

Happy Learning !!