Identify whether the string is a actual string or hexadecimal.

[shan raj]

Hi,

I have one string variable temp which holds either String or hexadecimal string.
for e.g:

    
String temp = "22DFC87A264FAE053679EB830000002A00000005"; //or "526f75746572"

 or 

String temp = "TestProj";

The next code should identify whether its a hexadecimal or string. Based on the identification I need to call another method.

Could some one suggest me the way to do this.

Thanks in Advance.
Shan

[Sagar Rohankar]

http://codingforums.com/showthread.php?t=68429

[shan raj]

I tried that logic and it is not working.

[Sagar Rohankar]

Which code/logic you tried ? Where was the problem ?

[shan raj]

The code is

          
String temp = "526F75746572";
        boolean ret;
        try {
            // try to parse the string to an integer, using 16 as radix
            int t = Integer.parseInt(temp, 16);
            // parsing succeeded, string is valid hex number
            ret = true;
        } catch (NumberFormatException e) {
            e.printStackTrace();
            // parsing failed, string is not a valid hex number
            ret = false;
        }

        System.out.println("Is Hex String=" + ret);
  

Expected output is "Is Hex String= true". But it says false and throws an NumberFormatException

[Rob Spoor]

That's because the number is too large to fit into an int. Long.parseLong may work but can run into the same problem. BigInteger is also an option.

I'd follow the advise of the first reply there - use a Pattern to check. See java.util.regex.Pattern.

[Sagar Rohankar]

OR if you have an extensive use of Hex, decimal, binary, etc then try using
Apache Commons CodecHex class

[Stefan Brandenberger]

shan raj wrote:The code is

          
String temp = "526F75746572";
        boolean ret;
        try {
            // try to parse the string to an integer, using 16 as radix
            int t = Integer.parseInt(temp, 16);
            // parsing succeeded, string is valid hex number
            ret = true;
        } catch (NumberFormatException e) {
            e.printStackTrace();
            // parsing failed, string is not a valid hex number
            ret = false;
        }

        System.out.println("Is Hex String=" + ret);
  

Expected output is "Is Hex String= true". But it says false and throws an NumberFormatException

Hi shan

If you want to do it that way, you have to check each digit, not the whole string at once.

Stefan

[David Newton]

Are there any cases where a string migt look like a hexadecimal number but be intended to be a string? (A place I worked at ran in to that. Think of things like "beef" or "cafe".)

[Rob Spoor]

Or cafebabe of course