字符串，int,十六进制相互转换

public class TypeConvert       {
/* 字符串转byte[]
这个方法转换后的结果是会多一些 48字符进来的就是代表的是0不知道为什么，但是可以只是取出指定的字符串
*/
public static byte[] hexStringToBytes(String hexString)
{
if (hexString == null || hexString.equals(""))
{
return null;
}
hexString = hexString.toUpperCase();
int length = hexString.length() / 2;
char[] hexChars = hexString.toCharArray();
byte[] d = new byte[length];
for (int i = 0; i < length; i++) {
int pos = i * 2;
d[i] = (byte) (charToByte(hexChars[pos]) << 4 | charToByte(hexChars[pos + 1]));
}
return d;
}

/* byte转short */
public final static short getShort(byte[] buf, boolean asc, int len) {
short r = 0;
if (asc)
for (int i = len - 1; i >= 0; i--) {
r <<= 8;
r |= (buf[i] & 0x00ff);
}
else
for (int i = 0; i < len; i++) {
r <<= 8;
r |= (buf[i] & 0x00ff);
}

return r;
}

/* B2 -> 0xB2 */
public static int stringToByte(String in, byte[] b) throws Exception {
if (b.length < in.length() / 2) {
throw new Exception("byte array too small");
}

int j=0;
StringBuffer buf = new StringBuffer(2);
for (int i=0; i<in.length(); i++, j++) {
buf.insert(0, in.charAt(i));
buf.insert(1, in.charAt(i+1));
int t = Integer.parseInt(buf.toString(),16);
System.out.println("byte hex value:" + t);
b[j] = (byte)t;
i++;
buf.delete(0,2);
}

return j;
}

/* byte to  int */
public final static int getInt(byte[] buf, boolean asc, int len) {
if (buf == null) {
throw new IllegalArgumentException("byte array is null!");
}
if (len > 4) {
throw new IllegalArgumentException("byte array size > 4 !");
}
int r = 0;
if (asc)
for (int i = len - 1; i >= 0; i--) {
r <<= 8;
r |= (buf[i] & 0x000000ff);
}
else
for (int i = 0; i < len; i++) {
r <<= 8;
r |= (buf[i] & 0x000000ff);
}
return r;
}

/* int -> byte[] */
public static byte[] intToBytes(int num) {
byte[] b = new byte[4];
for (int i = 0; i < 4; i++) {
b[i] = (byte) (num >>> (24 - i * 8));
}

return b;
}

/* short to byte[] */
public static byte[] shortToBytes(short num) {
byte[] b = new byte[2];

for (int i = 0; i < 2; i++) {
b[i] = (byte) (num >>> (i * 8));
}

return b;
}

/* byte to String */
private static char findHex(byte b) {
4000

int t = new Byte(b).intValue();
t = t < 0 ? t + 16 : t;

if ((0 <= t) &&(t <= 9)) {
return (char)(t + '0');
}

return (char)(t-10+'A');
}
public static String byteToString(byte b) {
byte high, low;
byte maskHigh = (byte)0xf0;
byte maskLow = 0x0f;

high = (byte)((b & maskHigh) >> 4);
low = (byte)(b & maskLow);

StringBuffer buf = new StringBuffer();
buf.append(findHex(high));
buf.append(findHex(low));

return buf.toString();
}

/* short -> byte */
public final static byte[] getBytes(short s, boolean asc) {
byte[] buf = new byte[2];
if (asc)      for (int i = buf.length - 1; i >= 0; i--) {  buf[i] = (byte) (s & 0x00ff);
s >>= 8;
}
else
for (int i = 0; i < buf.length; i++) {
buf[i] = (byte) (s & 0x00ff);
s >>= 8;
}
return buf;
}
/* int -> byte[] */
public final static byte[] getBytes(int s, boolean asc) {
byte[] buf = new byte[4];
if (asc)
for (int i = buf.length - 1; i >= 0; i--) {
buf[i] = (byte) (s & 0x000000ff);
s >>= 8;
}
else
for (int i = 0; i < buf.length; i++) {
buf[i] = (byte) (s & 0x000000ff);
s >>= 8;
}
return buf;
}

/* long -> byte[] */
public final static byte[] getBytes(long s, boolean asc) {
byte[] buf = new byte[8];
if (asc)
for (int i = buf.length - 1; i >= 0; i--) {
buf[i] = (byte) (s & 0x00000000000000ff);
s >>= 8;
}
else
for (int i = 0; i < buf.length; i++) {
buf[i] = (byte) (s & 0x00000000000000ff);
s >>= 8;
}
return buf;
}

/* byte[]->int */
public final static int getInt(byte[] buf, boolean asc) {
if (buf == null) {
throw new IllegalArgumentException("byte array is null!");
}
if (buf.length > 4) {
throw new IllegalArgumentException("byte array size > 4 !");
}
int r = 0;
if (asc)
for (int i = buf.length - 1; i >= 0; i--) {
r <<= 8;
r |= (buf[i] & 0x000000ff);
}
else
for (int i = 0; i < buf.length; i++) {
r <<= 8;
r |= (buf[i] & 0x000000ff);
}
return r;
}
/* byte[] -> long */
public final static long getLong(byte[] buf, boolean asc) {
if (buf == null) {
throw new IllegalArgumentException("byte array is null!");
}
if (buf.length > 8) {
throw new IllegalArgumentException("byte array size > 8 !");
}
long r = 0;
if (asc)
for (int i = buf.length - 1; i >= 0; i--) {
r <<= 8;
r |= (buf[i] & 0x00000000000000ff);
}
else
for (int i = 0; i < buf.length; i++) {
r <<= 8;
r |= (buf[i] & 0x00000000000000ff);
}
return r;
}
}