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

String to Hexadecimal

The toHexString() method of the Integer class accepts an integer as a parameter and returns a hexadecimal string. Therefore, to convert a string to a hexadecimal String −

• 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

import java.util.Scanner;
public class StringToHexadecimal {
   public static void main(String args[]) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter a String value: ");
      String str = sc.next();
      StringBuffer sb = new StringBuffer();
      //Converting string to character array
      char ch[] = str.toCharArray();
      for(int i = 0; i < ch.length; i++) {
         String hexString = Integer.toHexString(ch[i]);
         sb.append(hexString);
      }
      String result = sb.toString();
      System.out.println(result);
   }
}

Output

Enter a String value:
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5475746f7269616c73706f696e74

Hexadecimal to string

In the same way to convert a hexadecimal (String) value 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

import java.util.Scanner;
public class HexadecimalToString {
   public static void main(String args[]) {
      Scanner sc = new Scanner(System.in);
      System.out.println("Enter a Hexadecimal value: ");
      String str = sc.next();
      String result = new String();
      char[] charArray = str.toCharArray();
      for(int i = 0; i < charArray.length; i=i+2) {
         String st = ""+charArray[i]+""+charArray[i+1];
         char ch = (char)Integer.parseInt(st, 16);
         result = result + ch;
      }
      System.out.println(result);
   }
}

Output

Enter a Hexadecimal value:
5475746f7269616c73706f696e74
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