Methods to Convert and Print Byte array to Hex String in Java? Instance

The problem with Printing Byte arrays as String

A few of you is likely to be questioning, why cannot we use String constructor which accepts byte array e.g. new String(byte[]). Nicely, the true challenge with printing byte array is non-printable ASCII characters.  Your MD5 checksum or any byte array might include some non-printable characters, which implies you cannot examine two-byte arrays by their String illustration. 

By the best way, this isn’t an issue if you are encoding String in base64, as they solely use printable ASCII characters. In our code instance of printing byte array as regular String, you possibly can see completely different strings, generated from completely different byte arrays, seems the identical. 


Since 0, 5 and 6 signify non-printable characters ASCII characters NUL, ENQ and ACK, they’re exhibiting right here as white area here. This challenge could be resolved if we convert byte array to Hexadecimal String, after which print or show it.

Advantages of Printing Byte array as Hex String in Java

There are a few advantages of printing byte array as Hex String in Java. In truth, displaying byte array as Hex String is regular apply, particularly once you wish to see and examine MD5 hash or digest worth, generated by the cryptographic algorithm.

1) It is simple to show contents of byte array in a typical method, as byte array might include non-printable characters.

2) Hex String permits you to shortly examine two-byte arrays contents.

3) Hex String is simple to learn, in comparison with binary or decimal format because it takes fewer digits.

These are some notable advantages of printing byte array as a hex string in Java.

2 methods to Convert Byte Array to Hex String in Java

import java.util.logging.Logger;
import org.apache.commons.codec.binary.Hex;

/**
 * Java program to transform Byte array to Hex String in Java.
 * This Java instance makes use of core Java and Apache commons code to
 * generate Hexadecimal String from byte array in Java.
 *
 * @writer Javin Paul
 */
public class ByteArrayToHexString {
    non-public static remaining Logger logger = Logger.getLogger(StringReplace.class.getName());
    
    public static void principal(String args[]) {
       
       //byte array with non printable characters 
       byte[] bytes = new byte[]{'a', 'b', 0, 5, 'c','d'};
       byte[] nonprintable = new byte[]{'a', 'b', 0, 6, 'c','d'};
     
       //You cannot print byte array as String as a result of they could include non printable
       //characters e.g. 0 is NUL, 5 is ENQ and 6 is ACK in ASCII format
      
       String worth = new String(bytes);
       System.out.println(worth);      
       String str = new String(nonprintable);
       System.out.println(str);   
      
       //Changing byte array to Hex String in Java for printing
       System.out.println("Byte array to Hex String in Java :                       " 
                                   + bytesToHexString(bytes));     
      
       //Apache commons codec to transform byte array to Hex String in Java
       String hex = Hex.encodeHexString(bytes);
       System.out.println("Byte array to Hexadecimal String utilizing Apache commons:   " 
                                  + hex);
    }
   
    public static String bytesToHexString(byte[] bytes){
        StringBuilder sb = new StringBuilder();
        for(byte b : bytes){
            sb.append(String.format("%02x", b&0xff));
        }
        return sb.toString();
    }  
   
}

Output:
ab  cd
ab  cd
Byte array to Hex String in Java :                       616200056364
Byte array to Hexadecimal String utilizing Apache commons:   616200056364

As I defined within the part challenge with printing byte arrays, character after “ab” will not be white area, it is a NUL ASCII character, however exhibiting as white area right here. Attempt working this Java program in your machine, and copying the primary line of output, you possibly can solely copy the primary two characters.

That is all on Methods to convert byte array to Hex String in Java. As I mentioned, the byte array might include some non-printable characters, which can produce a deceptive worth whereas printing them as regular String. It is all the time finest to show the contents of the byte array as a hex string in Java.

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