How to Convert a String to Hexadecimal and vice versa format in java?

In this article, we will learn how to convert a string to hexadecimal and hexadecimal to string in Java. Hexadecimal is a base-16 number system that uses 16 symbols to represent a number. Those symbols can be 0-9 and A-F letters.

String to Hexadecimal in Java

To convert a string to hexadecimal in Java, we can use the toHexString() method of the Integer class accepts an integer as a parameter and returns a hexadecimal string. Following are the steps to convert a string to hexadecimal:

• Get the desired String.
• Create an empty StringBuffer object.
• Convert it into a character array using the toCharArray() method of the String class.
• Traverse through the contents of the array created above, using a loop.
• Within the loop, convert each character of the array into an integer and pass it as a parameter to the toHexString() method of the Integer class.
• Append the resultant values to the StringBuffer object using the append() method of the StringBuffer class.
• Finally, convert the StringBuffer object to a string using the toString() method of the StringBuffer class

Example of String to Hexadecimal

Following is the Java program to convert a string to hexadecimal:

public class StringToHex{
   public static void main(String args[]){
      String str = "TutorialsPoint";
      StringBuffer sb = new StringBuffer();
      char ch[] = str.toCharArray();
      for(int i = 0; i < ch.length; i++){
         String hex = Integer.toHexString(ch[i]);
         sb.append(hex);
      }
      String ans = sb.toString();
      System.out.println("The hexadecimal value of the string is: " + ans);
   }
}

Output

When the above code is executed, it produces the following output:

The hexadecimal value of the string is: 5475746f7269616c73506f696e74

Hexadecimal to String in Java

To convert a hexadecimal string to a string in Java, we can use the parseInt() method of the Integer class. This method accepts a string and a radix as parameters and returns an integer. The following are the steps to convert a hexadecimal string to a string:

• Get the hexadecimal value (String).
• Convert it into a character array using the toCharArray() method.
• Read each two characters from the array and convert them into a String.
• Parse above obtained string into base 16 integer, cast it into a character.
• Concat all the characters to a string.

Example of Hexadecimal to String

Following is the Java program to convert a hexadecimal string to a string:

public class HexToString{
   public static void main(String args[]){
      String str = "5475746f7269616c73506f696e74";
      StringBuffer sb = new StringBuffer();
      char ch[] = str.toCharArray();
      for(int i = 0; i < ch.length; i+=2){
         String s = "" + ch[i] + ch[i+1];
         char c = (char)Integer.parseInt(s, 16);
         sb.append(c);
      }
      System.out.println("The string value of the hexadecimal is: " + sb.toString());
   }
}

Output

When the above code is executed, it produces the following output:

The string value of the hexadecimal is: TutorialsPoint