java生成随机数，16进制字符串和二进制binary字符串

class ByteSumSt {
public ByteSumSt(byte[] bDest, int bDestLen) {
this.bDest = bDest;
this.bDestLen = bDestLen;
}
byte[] bDest;
int bDestLen;
}

public static ByteSumSt TransUtilsGenerateRandom(int randomLength, boolean isHex) {
    int capacityLength = isHex ? randomLength * 2 : randomLength;
    byte[] bRandom = new byte[capacityLength];
    for (int i = 0; i < randomLength; i++) {
        double dr = Math.random();
        byte rByte = (byte)(dr * 256);
        if (isHex) {
            String strHex = Integer.toHexString(rByte & 0x0FF);
            if (1 == strHex.length()) {
                strHex = "0" + strHex;
            }
            bRandom[i * 2] = strHex.getBytes(StandardCharsets.UTF_8)[0];
            bRandom[i * 2 + 1] = strHex.getBytes(StandardCharsets.UTF_8)[1];
        } else {
            bRandom[i] = rByte;
        }
    }
    return new ByteSumSt(bRandom, capacityLength);
}

使用
ByteSumSt randomKey = TransUtilsGenerateRandom(16, false);
ishex为true时输出的是十六进制表示的字符串