不同进制的数字字符串互相转换

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[i] = (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[i]);
   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[i]& 0xf0)>>>4));
   temp.append((byte)(bytes[i]& 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[p] = 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[i] & 0xf0) >>> 4);
   int l = (bytes[i] & 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];
  }

 }
}