Split a String in Java with Examples

Undoubtedly String class from java.lang package is the most widely used class in Java programming language. If you are creating a school or college project or even an enterprise-level project you would see this is the most instantiated object!

A very common scenario one might come across while working with String class is how to split a string?

You can make use of the split method from the java.lang.String class.

Split method: public String[] split(String regex)

What does this method do? As you can see the split method takes in one argument of type String which is a regex (Regular Expression), so this method splits the string as per the provided regular expression.

Note that this method can throw a PatternSyntaxException if the regular expression syntax is not valid.

✌️ The spit(String regex) method was introduced in Java 1.4

Example 1. Split a String by comma (,)

Let's see an example, we have a String that is comma-separated containing names of Countries "USA, Japan, China, Austalia, Canada, Germany, France, Sweden, India, Sri Lanka, Russia, Poland" and we want to split this string by comma.

package com.code2care.java.tutorials;

public class JavaStringSplitExample {

	public static void main(String[] args) {

	String countries = "USA, Japan, China, Austalia, Canada, Germany, "
			+ "France, Sweden, India, Sri Lanka, Russia, Poland";

	String[] countriesArr = countries.split(",");

	for (String country : countriesArr) {
		System.out.println(country.trim());
	}
 }
}

USA
Japan
China
Austalia
Canada
Germany
France
Sweden
India
Sri Lanka
Russia
Poland

Example 2. Split a String by Slash (/)

String dataString = "11/22/2020";
String[] dateStringArr = dataString.split("/");
System.out.println("Date: " + dateStringArr[0]);
System.out.println("Month: " + dateStringArr[1]);
System.out.println("Year: " + dateStringArr[2]);

Date: 11
Month: 22
Year: 2020

Example 3. Split a String by Pipe (//|)

The first two examples we say worked by just passing the delimited as a string! Beware this will not work when the delimiter is a Pipe (you will get incorrect output) that's because the pipe has a special meaning in regEx, so you need to escape it using a backslash to use it as a character. Just add a double-slash \\ followed by |.

String operatingSystems = "macOS|Windows|Linux|Unix";
String[] operatingSystemsArr = operatingSystems.split("\\|");

for (String os : operatingSystemsArr) {
	System.out.println(os);
}

macOS
Windows
Linux
Unix

Example 4. Split a String by dot \\.)

Just like a pipe, the dot has a special meaning while using regEx so you need to escape it.

public static void main(String[] args) {

	String dataString = "111.2222.3333.4444";
	String[] dataStringArr = dataString.split("\\.");
	for (String data : dataStringArr) {
		System.out.println(data);
	}
}

Exception: java.util.regex.PatternSyntaxException:

If the provided regEx is invalid then you would see the below error stack,

Exception in thread "main" java.util.regex.PatternSyntaxException: Illegal repetition near index 0
${,}
^
	at java.base/java.util.regex.Pattern.error(Pattern.java:2027)
	at java.base/java.util.regex.Pattern.closure(Pattern.java:3320)
	at java.base/java.util.regex.Pattern.sequence(Pattern.java:2213)
	at java.base/java.util.regex.Pattern.expr(Pattern.java:2068)
	at java.base/java.util.regex.Pattern.compile(Pattern.java:1782)
	at java.base/java.util.regex.Pattern.<init>(Pattern.java:1428)
	at java.base/java.util.regex.Pattern.compile(Pattern.java:1068)
	at java.base/java.lang.String.split(String.java:2317)
	at java.base/java.lang.String.split(String.java:2364)
	at com.code2care.java.tutorials.JavaStringSplitExample.main(JavaStringSplitExample.java:8)