Java Utililty Methods String to Byte Array

byte[] asBytes(String basicString)
Get the corresponding byte array for a basic string.

final byte[] b = new byte[basicString.length()];
for (int i = 0; i < b.length; ++i) {
 b[i] = (byte) basicString.charAt(i);
return b;

byte[] asBytes(String hex)
as Bytes

if (hex.indexOf(' ') >= 0) {
 hex = hex.replaceAll(" ", "");
if (hex.startsWith("0x")) {
 hex = hex.substring(2);
return hexToBytes(hex);

byte[] asBytes(String hexStr)
as Bytes

if (hexStr.length() < 1) {
 return null;
byte[] result = new byte[hexStr.length() / 2];
int high, low;
for (int i = 0; i < hexStr.length() / 2; i++) {
 high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16);
 low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16);
...

byte[] convertStringToByte(String input)
convert String To Byte

return input == null ? new byte[0] : input.getBytes();

byte convertStringToByte(String strValue)
Converts a given string into a byte of one integer

try {
 byte intRegVal = 0;
 for (int i = strValue.length(); i > 0; i--) {
 intRegVal = (byte) (intRegVal + ((int) Math.pow(16, strValue.length() - i))
 * Integer.parseInt(strValue.substring(i - 1, i), 16));
 return intRegVal;
} catch (NumberFormatException e) {
...

byte[] convertStringToByteArray(String input)
Helper-method to emulate the getByte() method missing from the JRE emulation library.

char[] chars = input.toCharArray();
byte[] bytes1 = new byte[chars.length * 2];
int i = 0;
for (char c : chars) {
 if (c < 128) {
 bytes1[i] = (byte) c;
 i++;
 } else {
...

byte[] convertStringToByteArray(String string)
convert String To Byte Array

if (string == null) {
 throw new IllegalArgumentException("String argument must not be null!");
if (string.length() % 2 != 0) {
 throw new IllegalArgumentException("String argument has to have a length which can be divided by 2!");
byte[] bytes = new byte[string.length() / 2];
StringBuffer buffer = new StringBuffer(string);
...

byte[] convertStringToBytes(String string)
convert String To Bytes

if (string.length() % 2 != 0) {
 throw new IllegalArgumentException("Illegal HEX string '" + string
 + "' provided! The number of character needs to be dividable by 2.");
byte[] result = new byte[string.length() / 2];
char[] chars = new char[string.length()];
string.getChars(0, string.length(), chars, 0);
for (int i = 0; i < string.length() / 2; i++) {
...

byte[] getBytes(String k)
get Bytes

if (k == null || k.length() == 0) {
 throw new IllegalArgumentException("Key must not be blank");
try {
 return k.getBytes("utf-8");
} catch (UnsupportedEncodingException e) {
 throw new RuntimeException(e);

byte[] getBytes(String k)
get Bytes

if (k == null || k.length() == 0) {
 throw new IllegalArgumentException("Key must not be blank");
try {
 return k.getBytes(DEFAULT_CHARSET_NAME);
} catch (UnsupportedEncodingException e) {
 throw new RuntimeException(e);