Hex Your Bytes to Display(转载)

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2006/04/28

Have you ever needed to convert a byte array (byte []) into a displayable hex string? The JDK does not provide this capability for byte arrays, only for the wrapper classes.
Below is the code which will convert a byte array into a displayable "hex" representation of the string.
Now you can turn
		 byte b[] = {0xf1, 0x0d,  0x3c, 0x44};
		
into:
		 String s =  "F10D3C44"
		
like this:
		 String s =  byteArrayToHexString(b);
		
provides the same functionality found in Integer.toHexString(), Short.toHexString(), etc...

Simple to use

Fast, efficient and accurate

Tested and proven

Here's the code:
	 /**

	* Convert a byte[] array to readable string format. This makes the "hex"readable!

	* @return result String buffer in String format 

	* @param in byte[] buffer to convert to string format

	*/

	static String byteArrayToHexString(byte in[]) {

	    byte ch = 0x00;

	    int i = 0; 

	    if (in == null || in.length <= 0)

	        return null;

	        

	    String pseudo[] = {"0", "1", "2","3", "4", "5", "6", "7", "8","9", "A", "B", "C", "D", "E","F"};

	    StringBuffer out = new StringBuffer(in.length * 2);

	    

	    while (i < in.length) {

	        ch = (byte) (in[i] & 0xF0); // Strip offhigh nibble

	        ch = (byte) (ch >>> 4);     // shift the bits down

	        ch = (byte) (ch & 0x0F);    // must do this is high order bit is on!

	        out.append(pseudo[ (int) ch]); // convert thenibble to a String Character

	        ch = (byte) (in[i] & 0x0F); // Strip offlow nibble 

	        out.append(pseudo[ (int) ch]); // convert thenibble to a String Character

	        i++;

	    }

	    String rslt = new String(out);

	    return rslt;

	}    

	
Stay tuned, I'll present some additional routines which take the "hex" data and format it into a "Hex Dump" format like: 0000: 32 00 00 00 00 49 99 04 13 14 56 20 17 55 2B 3F ____[2 I™V U+?]
0010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ____[ ]
0020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ____[ ]
The above example was created using byteArrayToHexString() along with another routine....I also have a hex dump routine which dumps the hex data in "old" mainframe EBCDIC style format where each byte is display one nibble on top of the other.