byte数组与String 互转

/**
* 将byte[]数组转化为String类型
*
* @param arg 需要转换的byte[]数组
* @param length 需要转换的数组长度
* @return 转换后的String队形
*/
private String toHexString(byte[] arg, int length) {
String result = new String();
if (arg != null) {
for (int i = 0; i < length; i++) {
result = result
+ (Integer.toHexString(
arg[i] < 0 ? arg[i] + 256 : arg[i]).length() == 1 ? "0"
+ Integer.toHexString(arg[i] < 0 ? arg[i] + 256
: arg[i])
: Integer.toHexString(arg[i] < 0 ? arg[i] + 256
: arg[i])) + " ";
}
return result;
}
return "";
}

/**
 * 将String转化为byte[]数组
 *
 * @param arg 需要转换的String对象
 * @return 转换后的byte[]数组
 */
private byte[] toByteArray(String arg) {
    if (arg != null) {
        /* 1.先去除String中的' '，然后将String转换为char数组 */
        char[] NewArray = new char[1000];
        char[] array = arg.toCharArray();
        int length = 0;
        for (int i = 0; i < array.length; i++) {
            if (array[i] != ' ') {
                NewArray[length] = array[i];
                length++;
            }
        }
        /* 将char数组中的值转成一个实际的十进制数组 */
        int EvenLength = (length % 2 == 0) ? length : length + 1;
        if (EvenLength != 0) {
            int[] data = new int[EvenLength];
            data[EvenLength - 1] = 0;
            for (int i = 0; i < length; i++) {
                if (NewArray[i] >= '0' && NewArray[i] <= '9') {
                    data[i] = NewArray[i] - '0';
                } else if (NewArray[i] >= 'a' && NewArray[i] <= 'f') {
                    data[i] = NewArray[i] - 'a' + 10;
                } else if (NewArray[i] >= 'A' && NewArray[i] <= 'F') {
                    data[i] = NewArray[i] - 'A' + 10;
                }
            }
            /* 将 每个char的值每两个组成一个16进制数据 */
            byte[] byteArray = new byte[EvenLength / 2];
            for (int i = 0; i < EvenLength / 2; i++) {
                byteArray[i] = (byte) (data[i * 2] * 16 + data[i * 2 + 1]);
            }
            return byteArray;
        }
    }
    return new byte[]{};
}