src/main/java/com/alipay/remoting/config/switches/ProtocolSwitch.java
public static byte toByte(BitSet bs) {
        int value = 0;
        for (int i = 0; i < bs.length(); ++i) {
            if (bs.get(i)) {
                value += 1 << i;
            }
        }
        if (bs.length() > 7) {
            throw new IllegalArgumentException("The byte value " + value
                                               + " generated according to bit set " + bs
                                               + " is out of range, should be limited between ["
                                               + Byte.MIN_VALUE + "] to [" + Byte.MAX_VALUE + "]");
        }
        return (byte) value;
    }
public static byte toByte(BitSet bs) {
        int value = 0;
        for (int i = 0; i < bs.length(); ++i) {
            if (bs.get(i)) {
                value += 1 << i;
            }
        }
        if (bs.length() > 7) {
            throw new IllegalArgumentException("The byte value " + value
                                               + " generated according to bit set " + bs
                                               + " is out of range, should be limited between ["
                                               + Byte.MIN_VALUE + "] to [" + Byte.MAX_VALUE + "]");
        }
        return (byte) value;
    }
from bit set to byte
@param bs
@return byte represent the bit set