32位随机字符串工具类-RandomGUIDUtil

电玩女神 2022-05-21 08:09 818阅读 0赞

import org.apache.log4j.Logger;
    
    import java.net.InetAddress;
    import java.net.UnknownHostException;
    import java.security.MessageDigest;
    import java.security.NoSuchAlgorithmException;
    import java.security.SecureRandom;
    import java.util.Random;
    
    public class RandomGUIDUtil {
       /** 日志管理类对象 */ private Logger logger = Logger.getLogger(this.getClass().getName());
       public String valueBeforeMD5 = "";
       public String valueAfterMD5 = "";
       private static Random myRand;
       private static SecureRandom mySecureRand;
       private static String s_id;
    
       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();
       }
    
       public static void main(String[] args) throws Exception{
          System.out.println(RandomGUIDUtil.newGuid());
       }
    }