16进制字符串与byte数组互转（转载）

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public final class Converts {
public final static char[] BToA = "0123456789abcdef".toCharArray() ;
private Converts() {
}
/**
* 把16进制字符串转换成字节数组
* @param hex
* @return
*/
public static byte[] hexStringToByte(String hex) {
int len = (hex.length() / 2);
byte[] result = new byte[len];
char[] achar = hex.toCharArray();
for (int i = 0; i < len; i++) {
  int pos = i * 2;
  result = (byte) (toByte(achar[pos]) << 4 | toByte(achar[pos + 1]));
}
return result;
}
private static byte toByte(char c) {
byte b = (byte) "0123456789ABCDEF".indexOf(c);
return b;
}
/**
* 把字节数组转换成16进制字符串
* @param bArray
* @return
*/
public static final String bytesToHexString(byte[] bArray) {
StringBuffer sb = new StringBuffer(bArray.length);
String sTemp;
for (int i = 0; i < bArray.length; i++) {
  sTemp = Integer.toHexString(0xFF & bArray);
  if (sTemp.length() < 2)
  sb.append(0);
  sb.append(sTemp.toUpperCase());
}
return sb.toString();
}
/**
* 把字节数组转换为对象
* @param bytes
* @return
* @throws IOException
* @throws ClassNotFoundException
*/
public static final Object bytesToObject(byte[] bytes) throws IOException, ClassNotFoundException {
ByteArrayInputStream in = new ByteArrayInputStream(bytes);
ObjectInputStream oi = new ObjectInputStream(in);
Object o = oi.readObject();
oi.close();
return o;
}
/**
* 把可序列化对象转换成字节数组
* @param s
* @return
* @throws IOException
*/
public static final byte[] objectToBytes(Serializable s) throws IOException {
ByteArrayOutputStream out = new ByteArrayOutputStream();
ObjectOutputStream ot = new ObjectOutputStream(out);
ot.writeObject(s);
ot.flush();
ot.close();
return out.toByteArray();
}

public static final String objectToHexString(Serializable s) throws IOException{
return bytesToHexString(objectToBytes(s));
}

public static final Object hexStringToObject(String hex) throws IOException, ClassNotFoundException{
return bytesToObject(hexStringToByte(hex));
}

/**
* @函数功能: BCD码转为10进制串(阿拉伯数据)
* @输入参数: BCD码
* @输出结果: 10进制串
*/
public static String bcd2Str(byte[] bytes){
StringBuffer temp=new StringBuffer(bytes.length*2);
for(int i=0;i<bytes.length;i++){
  temp.append((byte)((bytes& 0xf0)>>>4));
  temp.append((byte)(bytes& 0x0f));
}
return temp.toString().substring(0,1).equalsIgnoreCase("0")?temp.toString().substring(1):temp.toString();
}
/**
* @函数功能: 10进制串转为BCD码
* @输入参数: 10进制串
* @输出结果: BCD码
*/
public static byte[] str2Bcd(String asc) {
int len = asc.length();
int mod = len % 2;
if (mod != 0) {
  asc = "0" + asc;
  len = asc.length();
}
byte abt[] = new byte[len];
if (len >= 2) {
  len = len / 2;
}
byte bbt[] = new byte[len];
abt = asc.getBytes();
int j, k;
for (int p = 0; p < asc.length()/2; p++) {
  if ( (abt[2 * p] >= '0') && (abt[2 * p] <= '9')) {
  j = abt[2 * p] - '0';
  } else if ( (abt[2 * p] >= 'a') && (abt[2 * p] <= 'z')) {
  j = abt[2 * p] - 'a' + 0x0a;
  } else {
  j = abt[2 * p] - 'A' + 0x0a;
  }
  if ( (abt[2 * p + 1] >= '0') && (abt[2 * p + 1] <= '9')) {
  k = abt[2 * p + 1] - '0';
  } else if ( (abt[2 * p + 1] >= 'a') && (abt[2 * p + 1] <= 'z')) {
  k = abt[2 * p + 1] - 'a' + 0x0a;
  }else {
  k = abt[2 * p + 1] - 'A' + 0x0a;
  }
  int a = (j << 4) + k;
  byte b = (byte) a;
  bbt

= b;
}
return bbt;
}

public static String BCD2ASC(byte[] bytes) {
StringBuffer temp = new StringBuffer(bytes.length * 2);
for (int i = 0; i < bytes.length; i++) {
  int h = ((bytes & 0xf0) >>> 4);
  int l = (bytes & 0x0f);  
  temp.append(BToA[h]).append( BToA[l]);
}
return temp.toString() ;
}

/**
* MD5加密字符串，返回加密后的16进制字符串
* @param origin
* @return
*/
public static String MD5EncodeToHex(String origin) {
  return bytesToHexString(MD5Encode(origin));
  }

/**
* MD5加密字符串，返回加密后的字节数组
* @param origin
* @return
*/
public static byte[] MD5Encode(String origin){
return MD5Encode(origin.getBytes());
}

/**
* MD5加密字节数组，返回加密后的字节数组
* @param bytes
* @return
*/
public static byte[] MD5Encode(byte[] bytes){
MessageDigest md=null;
try {
  md = MessageDigest.getInstance("MD5");
  return md.digest(bytes);
} catch (NoSuchAlgorithmException e) {
  e.printStackTrace();
  return new byte[0];
}

}
}