Introduction:

String manipulation is a common task in programming, and converting strings to hexadecimal arrays is often required. Java, being a versatile programming language, offers multiple approaches to accomplish this task. In this blog, we will explore several methods for converting a string into a hex array in a specific format, along with code examples, outputs, and detailed explanations.

Method 1: Using the String.getBytes() Method

The String.getBytes() method converts a string into a byte array, which can then be converted into a hexadecimal representation. Here's an example:

public class StringToHexArrayConverter {

    public static String[] convertStringToHexArray(String input) {
        byte[] bytes = input.getBytes();
        String[] hexArray = new String[bytes.length];

        for (int i = 0; i < bytes.length; i++) {
            hexArray[i] = String.format("%02X", bytes[i]);
        }

        return hexArray;
    }

    public static void main(String[] args) {
        String input = "Hello, World!";
        String[] hexArray = convertStringToHexArray(input);

        for (String hexValue : hexArray) {
            System.out.print(hexValue + " ");
        }
    }
}

Output:

48 65 6C 6C 6F 2C 20 57 6F 72 6C 64 21 

• The getBytes() method converts the string into an array of bytes.
• We create a hexArray with the same length as the bytes array to store the hexadecimal values.
• Using a loop, we iterate through each byte and convert it to a hexadecimal string using String.format("%02X", bytes[i]).
• The %02X format ensures that each hexadecimal value is two characters long and in uppercase.
• Finally, we return the hexArray containing the hexadecimal representation of the string.

Method 2: Using BigInteger and String.format()

Another approach involves using the BigInteger class and the String.format() method for converting the string to a hex array. Here's an example:

import java.math.BigInteger;

public class StringToHexArrayConverter {

    public static String[] convertStringToHexArray(String input) {
        byte[] bytes = input.getBytes();
        String[] hexArray = new String[bytes.length];

        for (int i = 0; i < bytes.length; i++) {
            BigInteger bigInt = new BigInteger(1, new byte[]{bytes[i]});
            hexArray[i] = String.format("%02X", bigInt);
        }

        return hexArray;
    }

    public static void main(String[] args) {
        String input = "Hello, World!";
        String[] hexArray = convertStringToHexArray(input);

        for (String hexValue : hexArray) {
            System.out.print(hexValue + " ");
        }
    }
}

Output:

48 65 6C 6C 6F 2C 20 57 6F 72 6C 64 21 

• The getBytes() method converts the string into an array of bytes.
• We create a hexArray with the same length as the bytes array to store the hexadecimal values.
• Using a loop, we iterate through each byte and create a BigInteger object using the byte value.
• The BigInteger object is then formatted as a hexadecimal string using String.format("%02X", bigInt).
• Finally, we return the hexArray containing the hexadecimal representation of the string.

Conclusion:

In this blog post, we explored two methods for converting a string into a hex array in a specific format using Java. The first method utilized the String.getBytes() method, while the second method involved the use of BigInteger and String.format(). Both approaches provided the desired output, allowing us to convert strings into their hexadecimal representation conveniently.