Java String to String Array Conversion Examples

A quick and practical guide on how to convert String to String Array in different ways in java.

1. Overview

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

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.

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

package com.oraclejavacertified.programs.conversions.string;

public class StringtoStringArraySplit {

    public static void main(String[] args) {

        //  input string

        String input = "oraclejavacertified.blogspot.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 “oraclejavacertified.blogspot.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.oraclejavacertified.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.oraclejavacertified.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