Java Utililty Methods BitSet To Byte Array

String bitsetToBinary(BitSet set, int n)
bitset To Binary

StringBuilder sb = new StringBuilder();
for (int i = 0; i < n; i++)
 sb.append(set.get(i) ? "1" : "0");
return sb.toString();

String bitSetToBinaryString(BitSet b, int startBit, int length)
Convert a BitSet to a binary representation string.

return bitSetToBinaryString(b, startBit, length, 4);

String bitSetToBinaryString(BitSet strainBitSet)
Convert the bit set to its string representation

StringBuffer sb = new StringBuffer(strainBitSet.length());
for (int i = 0; i < strainBitSet.length(); i++) {
 sb.append(strainBitSet.get(i) ? '1' : '0');
return sb.toString();

byte[] bitSetToByteArray(BitSet bitSet, int bitSetLength)
bit Set To Byte Array

byte[] ret = bitSet.toByteArray();
if (ret.length == bitSetLength) {
 return ret;
byte[] finalRet = new byte[bitSetLength % 8 == 0 ? bitSetLength / 8 : bitSetLength / 8 + 1];
System.arraycopy(ret, 0, finalRet, 0, ret.length);
return finalRet;

byte[] bitSetToByteArray(BitSet bitSet, int byteLen)
bit Set To Byte Array

byte[] result = new byte[byteLen];
for (int i = 0; i < byteLen; i++) {
 for (int j = 7; j >= 0; j--) {
 if (bitSet.length() < (i * 8 + (7 - j)))
 return result;
 if (bitSet.get(i * 8 + (7 - j)))
 result[i] |= (0x01 << j);
return result;

byte[] bitSetToByteArray(final BitSet bitSet, final int numBytes)
This method makes up for a quirk in the standard java.util.BitSet class toByteArray() method, whereby high-end zero value bytes are discarded.

return Arrays.copyOf(bitSet.toByteArray(), numBytes);

byte[] bitSetToBytes(BitSet bs)
Copy a BitSet to a byte array

byte[] bytes = new byte[bs.size() / 8];
for (int i = 0; i < bytes.length; ++i) {
 for (int j = 0; j < 8; ++j) {
 if (bs.get(i * 8 + j))
 bytes[i] |= 1 << j;
return bytes;
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