生成全球唯一32位码
public class RandomGUIDUtil extends Object {
??? public String valueBeforeMD5 = "";
??? public String valueAfterMD5 = "";
??? private static Random myRand;
??? private static SecureRandom mySecureRand;
??? private static String s_id;
??? /*
???? *? 静态块初始化
???? */
??? static {
??????? mySecureRand = new SecureRandom();
??????? long secureInitializer = mySecureRand.nextLong();
??????? myRand = new Random(secureInitializer);
??????? try {
??????????? s_id = InetAddress.getLocalHost().toString();
??????? } catch (UnknownHostException e) {
??????????? System.out.println("构造带指定详细消息和嵌入异常!");
??????? }
??? }
??? public RandomGUIDUtil() throws Exception {
??????? getRandomGUID(false);
??? }
??? public RandomGUIDUtil(boolean secure) throws Exception {
??????? getRandomGUID(secure);
??? }
??? /*
???? * 随机生成GUID
???? */
??? private void getRandomGUID(boolean secure) throws Exception {
??????? MessageDigest md5 = null;
??????? StringBuffer sbValueBeforeMD5 = new StringBuffer();
??????? try {
??????????? md5 = MessageDigest.getInstance("MD5");
??????? } catch (NoSuchAlgorithmException e) {
??????????? logger.error("初始化MD5出错！");
??????????? throw new NoSuchAlgorithmException("初始化MD5出错！");
??????? }
??????? try {
??????????? long time = System.currentTimeMillis();
??????????? long rand = 0;
??????????? if (secure) {
??????????????? rand = mySecureRand.nextLong();
??????????? } else {
??????????????? rand = myRand.nextLong();
??????????? }
??????????? sbValueBeforeMD5.append(s_id);
??????????? sbValueBeforeMD5.append(":");
??????????? sbValueBeforeMD5.append(Long.toString(time));
??????????? sbValueBeforeMD5.append(":");
??????????? sbValueBeforeMD5.append(Long.toString(rand));
??????????? valueBeforeMD5 = sbValueBeforeMD5.toString();
??????????? md5.update(valueBeforeMD5.getBytes());
??????????? byte[] array = md5.digest();
??????????? StringBuffer sb = new StringBuffer();
??????????? for (int j = 0; j < array.length; ++j) {
??????????????? int b = array[j] & 0xFF;
??????????????? if (b < 0x10) sb.append('0');
??????????????? sb.append(Integer.toHexString(b));
??????????? }
??????????? valueAfterMD5 = sb.toString();
??????? } catch (Exception e) {
??????????? logger.error("获得MD5加密码出错!");
??????????? throw new Exception("初始化MD5出错！");
??????? }
??? }
??? /**
???? * 生成一个GUID串
???? * @return GUID
???? * @throws Exception
???? */
??? public static String newGuid() throws Exception{
??????? RandomGUIDUtil rdmGUID = new RandomGUIDUtil();
??????? return rdmGUID.toString();
??? }
??? /*
???? * 生成以主机串号、显卡串号、主板号，以保证唯一性的32位编码
???? */
??? public String toString() {
??????? String raw = valueAfterMD5.toUpperCase();
??????? StringBuffer sb = new StringBuffer();
??????? sb.append(raw.substring(0, 8));
??????? sb.append(raw.substring(8, 12));
??????? sb.append(raw.substring(12, 16));
??????? sb.append(raw.substring(16, 20));
??????? sb.append(raw.substring(20));
??????? return sb.toString();
??? }
}
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