There are many ways we can split a comma-separated String in Java. In this tutorial, we will cover the following:
- With a split() method
- Using the Java 8 Streams API
- Using the Splitter class from the Guava library
You might want to check the How to Split String in Java tutorial to see other examples.
Split a comma-separated String with a split() method
We can use the String[] split(String regex) of the String class that splits the String around matches of the given regular expression. This method splits String into an array.
Example
public class SplitString {
public static void main(String[] args) {
String names = "Tom,Steve,John,Megan,Melissa";
// split string
String[] arr = names.split(",");
// print the size of the array
System.out.println(arr.length);
// print the elements
Stream.of(arr).forEach(System.out::println);
}
}
List<String> list = Arrays.asList(names.split(","));
And If you need an ArrayList, then use this code:
List<String> list = new ArrayList<>(Arrays.asList(names.split(" , ")));
Note: If you have some whitespaces between commas and strings, you probably want to remove them.
To remove whitespaces, we need to provide the following regex: “\\s*,\\s*” as parameter to the split() method.
Example
// String with whitespaces after commas
String names = "Tom, Steve ,John, Megan, Melissa";
// split the string and remove any whitespace
List<String> = new ArrayList<>(Arrays.asList(names.split("\\s*,\\s*")));
Split the String using the Java 8 Streams API
It also can be done using the map() and collect() operators from the Java 8 Streams API.
Example
public class SplitString {
public static void main(String[] args) {
String names = "Tom,Steve,John,Megan,Melissa";
List<String> = Stream.of(names.split(","))
.map(String::trim)
.collect(Collectors.toList());
System.out.println(list.size());
list.forEach(System.out::println);
}
}
Using the Splitter class from the Guava library
The Splitter class from the guava library has some useful methods that we can use to split the String based on some separator.
To use it, you need to add the following dependency to your pom.xml:
<dependency>
<groupid>com.google.guava</groupid>
<artifactid>guava</artifactid>
<version>31.0.1-jre</version>
</dependency>
Example:
public class SplitString {
public static void main(String[] args) {
String names = "Tom,Steve,John,Megan,Melissa";
// returns an ArrayList
List<String> = Lists.newArrayList(Splitter.on(",").split(names));
System.out.println(list.size());
list.forEach(System.out::println);
}
}
// String with whitespaces after commas
String names = "Tom, Steve, John, Megan, Melissa";
// split the string and remove any whitespace
List<String> = Lists.newArrayList(Splitter.on(",").trimResults().split(names));
That’s all about how to split a comma-separated String in Java.