Java String to String Array Conversion Examples

1. Overview

In this article, you'll learn how to convert String to String Array in java with example programs.

Let us learn the different ways to do the conversion into a string array. from a string value.

2.  Using the split() method

String api is added with split() method which takes the delimiter as input and the string will be split based on the given delimiter. Finally, it returns each split string as in the form of String[] array.

In the previous article, we've seen in-depth about how to split a string using the split() method with different delimiters.

Look at the below program and passed the empty string "" to the split() method. 

package com.javaprogramto.programs.conversions.string;

public class StringtoStringArraySplit {

	public static void main(String[] args) {

		//  input string
		String input = "javaprogramto.com";
		
		// spliting string into string array using  split() method.
		String[] stringArray = input.split("");
		
		// printing the values of string array
		for (String string : stringArray) {
			System.out.println(string);
		}
	}

}
 

Output:

j
a
v
a
p
r
o
g
r
a
m
t
o
.
c
o
m
 

input.split("") method returns the string "javaprogramto.com" into string[] array and stores the result in the stringArray. Use the forEach loop to iterate and print the values of the String array.

Now, converted string array length and original string lengths should be the same. let us check now.

System.out.println(stringArray.length);
System.out.println(input.length());
 

Output:

17
17
 

3. Using Regular Expression

Next, Look at the second approach using regular expressions which simplifies the lots code for complexe validations such as validations of the email address and phone numbers.

Regular Expression Examples on removing the vowels from string and checking string is number.

Again need to use the split() method with the regular expression as below.

package com.javaprogramto.programs.conversions.string;

public class StringtoStringArraySplitRegularExpression {

	public static void main(String[] args) {

		//  input string
		String input = "hello geek";
		
		// splitting string into string array using  split() method with regular expression.
		String[] stringArray = input.split("(?!^)");
		
		// printing the values of string array
		for (String string : stringArray) {
			System.out.println(string);
		}
		
		System.out.println(stringArray.length);
		System.out.println(input.length());
		
	}

}

Output:

h
e
l
l
o
 
g
e
e
k
10
10

4. Using Guava

Guava API also has builtin support for string array conversions as below.

But when you are working with Guava there are many steps involved here.

4.1 First converts string to char[] array using toCharArray() method.

4.2. Chars.asList() method to convert char array into List.

4.3 Finally, it transforms into String array with List.transform() and toArray() methods.

These procedure is little bit java 8 concepts are required to understand.

Here is the full code example.

package com.javaprogramto.programs.conversions.string;

import org.apache.commons.lang3.ArrayUtils;

import com.google.common.base.Functions;
import com.google.common.collect.Lists;
import com.google.common.primitives.Chars;

public class StringtoStringArrayGuava {

	public static void main(String[] args) {

		// input string
		String input = "Using Guava";

		// spliting string into string array using split() method.
		String[] stringArray = Lists.transform(Chars.asList(input.toCharArray()), Functions.toStringFunction())
				.toArray(ArrayUtils.EMPTY_STRING_ARRAY);

		// printing the values of string array
		for (String string : stringArray) {
			System.out.println(string);
		}

		System.out.println(stringArray.length);
		System.out.println(input.length());

	}

}

Output:

U
s
i
n
g
 
G
u
a
v
a
11
11

5. Conclusion

In this article, you've seen how to convert string to string array examples using java builtin split(), regular expression, and finally with Guava api methods.

As usual, all examples are over GitHub.

java String split() API

Regular Expressions

Guava