Java String to String[] Example

Java example to convert string into string array using String.split() method and using java.util.regex.Pattern class.

Quick Reference:

//1. String to String[]

String blogName = "how to do in java";
String[] words = null;

// Method 1 :: using String.split() method
words = blogName.split(" ");				//[how, to, do, in, java]

// Method 2 :: using Pattern.split() method
Pattern pattern = Pattern.compile(" ");
words = pattern.split(blogName);			//[how, to, do, in, java]

//2. String[] to String

String newName = String.join(" ", words);	//"how to do in java"

1) Convert String to String[]

1.1) String.split()

Use split() method to split string into tokens by passing a delimiter (or regex) as method argument.

import java.util.Arrays;

public class Main 
{
	public static void main(String[] args) 
	{
		String names = "alex,brian,charles,david";
		String[] namesArray = null;
		
		//Split string with comma
		namesArray = names.split(",");
		
		//Verify array content
		System.out.println(Arrays.toString(namesArray));
	}
}

Output:

[alex, brian, charles, david]

1.2) Pattern.split()

In Java, Pattern is the compiled representation of a regular expression. Use Pattern.split() method to convert string to string array, and using pattern as delimiter.

import java.util.Arrays;

public class Main 
{	
	public static void main(String[] args) 
	{
		String names = "alex,brian,charles,david";
		String[] namesArray = null;
		
		//Split string with comma
		Pattern pattern = Pattern.compile(",");
		namesArray = pattern.split( names );
		
		//Verify array content
		System.out.println(Arrays.toString(namesArray));
	}
}

Output:

[alex, brian, charles, david]

2) String[] to String

Use String.join() method to create string from String array. You need to pass two method arguments i.e.

1. delimiter – the delimiter that separates each element
2. array elements – the elements to join together

It will then return a new string that is composed of the ‘array elements’ separated by the ‘delimiter’.

public class Main 
{
	public static void main(String[] args) 
	{
		String[] tokens = {"How","To","Do","In","Java"};
		
		String blogName1 = String.join("", tokens);		//without space

		String blogName2 = String.join(" ", tokens);	//with one space

		String blogName3 = String.join("-", tokens);	//with hyphen
		
		//Verify string
		System.out.println(blogName1);
		System.out.println(blogName2);
		System.out.println(blogName3);
	}
}

Output:

HowToDoInJava
How To Do In Java
How-To-Do-In-Java

Drop me your questions in comments section.

Happy Learning !!

String.split() Java Doc
String.join() Java Doc
Pattern Java Doc
Arrays.toString() Java Doc