Android 16进制byte数组和16进制String，String之间转换

下面是从网上找的代码但是其中《16进制字符串转字节数组》有BUG无法转换0~15，下面有方法

/*16进制byte数组转String*/public static String bytes2HexString(byte[] b) {       String r = "";       for (int i = 0; i < b.length; i++) {           String hex = Integer.toHexString(b[i] & 0xFF);           if (hex.length() == 1) {               hex = '0' + hex;           }           r += hex.toUpperCase();       }       return r;   }/* * 16进制字符串转字节数组 */ public static byte[] hexString2Bytes(String hex) {     if ((hex == null) || (hex.equals(""))){         return null;     }     else if (hex.length()%2 != 0){         return null;     }     else{         hex = hex.toUpperCase();         int len = hex.length()/2;         byte[] b = new byte[len];         char[] hc = hex.toCharArray();         for (int i=0; i<len; i++){             int p=2*i;             b[i] = (byte) (charToByte(hc[p]) << 4 | charToByte(hc[p+1]));         }         return b;     } }/* * 字符转换为字节 */private static byte charToByte(char c) {    return (byte) "0123456789ABCDEF".indexOf(c);}

方法如下

/*String转byte数组*/public static byte[] Stringtobytes(String s) {    byte[] present = {};    if (Integer.parseInt(s) >= 16) {        present = hexString2Bytes(Integer.toHexString(Integer.parseInt(s)));    }else if(Integer.parseInt(s) == 0){        present = new byte[]{0x00};    }else if(Integer.parseInt(s) == 1){        present = new byte[]{0x01};    }else if(Integer.parseInt(s) == 2){        present = new byte[]{0x02};    }else if(Integer.parseInt(s) == 3){        present = new byte[]{0x03};    }else if(Integer.parseInt(s) == 4){        present = new byte[]{0x04};    }else if(Integer.parseInt(s) == 5){        present = new byte[]{0x05};    }else if(Integer.parseInt(s) == 6){        present = new byte[]{0x06};    }else if(Integer.parseInt(s) == 7){        present = new byte[]{0x07};    }else if(Integer.parseInt(s) == 8){        present = new byte[]{0x08};    }else if(Integer.parseInt(s) == 9){        present = new byte[]{0x09};    }else if(Integer.parseInt(s) == 10){        present = new byte[]{0x0a};    }else if(Integer.parseInt(s) == 11){        present = new byte[]{0x0b};    }else if(Integer.parseInt(s) == 12){        present = new byte[]{0x0c};    }else if(Integer.parseInt(s) == 13){        present = new byte[]{0x0d};    }else if(Integer.parseInt(s) == 14){        present = new byte[]{0x0e};    }else if(Integer.parseInt(s) == 15){        present = new byte[]{0x0f};    }    return present;}