Converting A String To Hexadecimal In Java

Question

I am trying to convert a string like \"testing123\" into hexadecimal form in java. I am currently using BlueJ.

And to convert it back, is it the same thing except b

Answer 1

Using Multiple Peoples help from multiple Threads..

I know this has been answered, but i would like to give a full encode & decode method for any others in my same situation..

Here's my Encoding & Decoding methods..

// Global Charset Encoding
public static Charset encodingType = StandardCharsets.UTF_8;

// Text To Hex
public static String textToHex(String text)
{
    byte[] buf = null;
    buf = text.getBytes(encodingType);
    char[] HEX_CHARS = "0123456789abcdef".toCharArray();
    char[] chars = new char[2 * buf.length];
    for (int i = 0; i < buf.length; ++i)
    {
        chars[2 * i] = HEX_CHARS[(buf[i] & 0xF0) >>> 4];
        chars[2 * i + 1] = HEX_CHARS[buf[i] & 0x0F];
    }
    return new String(chars);
}

// Hex To Text
public static String hexToText(String hex)
{
    int l = hex.length();
    byte[] data = new byte[l / 2];
    for (int i = 0; i < l; i += 2)
    {
        data[i / 2] = (byte) ((Character.digit(hex.charAt(i), 16) << 4)
            + Character.digit(hex.charAt(i + 1), 16));
    }
    String st = new String(data, encodingType);
    return st;
}

Answer 2

To ensure that the hex is always 40 characters long, the BigInteger has to be positive:

public String toHex(String arg) {
  return String.format("%x", new BigInteger(1, arg.getBytes(/*YOUR_CHARSET?*/)));
}

Answer 3

new BigInteger(1, myString.getBytes(/*YOUR_CHARSET?*/)).toString(16)