up vote 2 down vote favorite

My question is, I guess, quite simple :

How to convert a Byte to alpha-numeric char array (String) in java ?

I tried this but it gives me back an error on netbeans : 

 byte[] b = "test".getBytes("ASCII");
 String test = new String(b,"ASCII");

UPDATE : I am actually using this code : 

    byte[] b = "test".getBytes("ASCII");
    MessageDigest md = MessageDigest.getInstance("SHA-256");
    String bla = new String(md.digest(b), "ASCII");

But once I try to use for other stuff which requires String with ASCII, I receive the following errors like "This is not ASCII". I don't really understand, actually.

When I try to print it I got something weird like "2Q�h/�k�����"

Thank you in advance for your help.

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2  
OK, that byte vs. byte[] was just a typo... What's the error you're getting? – Lukas Eder Aug 27 '12 at 13:10
It doesn't want to compile according to netbeans... I don't understand. When I try to print b I got this kind of result : 2Q�h/�k�����U�b=���u����(��>T� – user1619114 Aug 27 '12 at 13:11
Are you sure your original String is ASCII? Please provide an example. – nkr Aug 27 '12 at 13:11
works for me, what error are you getting? – Eero Aaltonen Aug 27 '12 at 13:12
1  
No, you don't update it, you keep modifying the question. – Dan Aug 27 '12 at 13:32
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2 Answers

up vote 0 down vote

After your edits I think you want to generate a SHA-256 hash of a given String.

try {
    byte[] b = "test".getBytes("ASCII");
    MessageDigest md = MessageDigest.getInstance("SHA-256");
    byte[] hashBytes = md.digest(b);
    StringBuffer hexString = new StringBuffer();
    for (int i = 0; i < hashBytes.length; i++) {
        hexString.append(Integer.toHexString(0xFF & hashBytes[i]));
    }
    System.out.println(hexString);
} catch (Exception e) {
    e.printStackTrace();
}
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up vote 1 down vote

You're close :

public static void main(String[] args) throws java.io.UnsupportedEncodingException { //you should throw or catch this exception
   byte[] b = "test".getBytes("ASCII"); // And you must declare a byte array
   String test = new String(b,"ASCII");

   System.out.println(test); // Will output "test"
}
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Topic updated to make it more clear.* – user1619114 Aug 27 '12 at 13:25
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