How to decode hex code in an array in java

Question

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"));

Some remarks: in Java, classes always start with an upper case letter and variables ar writtein in camelCase and [] should be written behind the type, not behind the name (so String args[] becomes String[] args). If you want people to answer your question, you might want to format your code porperly (with regards to the remarks above as well as code indentation). — Turing85
– Turing85, Commented Jul 19, 2015 at 20:25
Please do not add a comment on your question or on an answer to say "Thank you" — Turing85
– Turing85, Commented Jul 19, 2015 at 20:28

Rahul Prasad · Accepted Answer · 2015-07-19 22:41:33Z

1

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();
            }
        }

edited Jul 19, 2015 at 22:41

answered Jul 19, 2015 at 21:20

Rahul Prasad

7571 gold badge9 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Arun Sivan Over a year ago

The solution was informative.I used the first code and it worked for me.When i used Hex.decodeHex(hexString .toCharArray()); I got an error.Is there any need to import special package for Hex.decodehex @user403348255

Rahul Prasad Over a year ago

Yes as indicated in commented part of code above: import org.apache.commons.codec.binary.Hex; //present in commons-codec-1.7.jar . You will have to download the jar and add it to your classpath.

Collectives™ on Stack Overflow

How to decode hex code in an array in java

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related