CODEWITHSUNDEEP
javaarrayshexdecoding
Arun Sivan
Arun Sivan

Reputation: 1810

How to decode hex code in an array in java

Need to decode hex code in array when accessed by index.User should enter array index and get decoded hex in array as output.

import java.util.Scanner;

  class Find {

  static String[] data={ " \\x6C\\x65\\x6E\\x67\\x74\\x68",
                       "\\x73\\x68\\x69\\x66\\x74"

                           //....etc upto 850 index

                        };

  public static void main(String[] args) {

  Scanner in = new Scanner(System.in);

  System.out.println("Enter a number");

  int s = in.nextInt();

  String decodeinput=data[s];

                          // need to add some code here 
                          //to decode hex and store to a string decodeoutput to print it

  String decodeoutput=......

  System.out.println();
                                          }
              }

How about using...

              String hexString ="some hex string";    

              byte[] bytes = Hex.decodeHex(hexString .toCharArray());

              System.out.println(new String(bytes, "UTF-8"));

Upvotes: 0

Views: 960

Answers (1)

Rahul Prasad
Rahul Prasad

Reputation: 757

Append the following code after getting the value of s from user. Imp: Please use camelCase convention for naming variables as pointed out above. I have just gone ahead and used the same names as you have for your convinience for now.

    if (s>= 0 && s < data.length) {
            String decodeinput = data[s].trim();

            StringBuilder decodeoutput = new StringBuilder();

            for (int i = 2; i < decodeinput.length() - 1; i += 4) {
                // Extract the hex values in pairs
                String temp = decodeinput.substring(i, (i + 2));
                // convert hex to decimal equivalent and then convert it to character
                decodeoutput.append((char) Integer.parseInt(temp, 16));
            }
            System.out.println("ASCII equivalent : " + decodeoutput.toString());
     }

OR, just complete what you were doing:

/*      import java.io.UnsupportedEncodingException;
        import org.apache.commons.codec.DecoderException;
        import org.apache.commons.codec.binary.Hex; //present in commons-codec-1.7.jar
*/
        if (s>= 0 && s < data.length)  {
            String hexString =data[s].trim();
            hexString = hexString.replace("\\x", "");
            byte[] bytes;
            try {
                bytes = Hex.decodeHex(hexString.toCharArray());
                System.out.println("ASCII equivalent : " + new String(bytes, "UTF-8"));
            } catch (DecoderException e) {
                e.printStackTrace();
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
        }

Upvotes: 1

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