java生成GUID代码

最新推荐文章于 2024-04-11 23:14:58 发布

原创最新推荐文章于 2024-04-11 23:14:58 发布 · 3k 阅读

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#java #string #random #sql server #exception #byte

package fops.presentation;

import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Random;

import com.lutris.appserver.server.httpPresentation.HttpPresentation;
import com.lutris.appserver.server.httpPresentation.HttpPresentationComms;
import com.lutris.appserver.server.httpPresentation.HttpPresentationException;

public class guid implements HttpPresentation {

   public String valueBeforeMD5 = "";
   public String valueAfterMD5 = "";
   private static Random myRand;
   private static SecureRandom mySecureRand;

   private static String s_id;
   private static final int PAD_BELOW = 0x10;
   private static final int TWO_BYTES = 0xFF;

   static {
      mySecureRand = new SecureRandom();
      long secureInitializer = mySecureRand.nextLong();
      myRand = new Random(secureInitializer);
      try {
         s_id = InetAddress.getLocalHost().toString();
      } catch (UnknownHostException e) {
         e.printStackTrace();
      }

}

   public guid() {
      getRandomGUID(false);
   }

   public guid(boolean secure) {
      getRandomGUID(secure);
   }

   /*
    * Method to generate the random GUID
    */
   private void getRandomGUID(boolean secure) {
      MessageDigest md5 = null;
      StringBuffer sbValueBeforeMD5 = new StringBuffer(128);

      try {
         md5 = MessageDigest.getInstance("MD5");
      } catch (NoSuchAlgorithmException e) {
       // logger.error("Error: " + e);
      }

      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(32);
         for (int j = 0; j < array.length; ++j) {
            int b = array[j] & TWO_BYTES;
            if (b < PAD_BELOW)
               sb.append('0');
            sb.append(Integer.toHexString(b));
         }

valueAfterMD5 = sb.toString();

      } catch (Exception e) {
        // logger.error("Error:" + e);
      }
   }

   /*
    * Convert to the standard format for GUID
    * (Useful for SQL Server UniqueIdentifiers, etc.)
    * Example: C2FEEEAC-CFCD-11D1-8B05-00600806D9B6
    */
   public String toString() {
      String raw = valueAfterMD5.toUpperCase();
      StringBuffer sb = new StringBuffer(64);
      sb.append(raw.substring(0, 8));
      sb.append("-");
      sb.append(raw.substring(8, 12));
      sb.append("-");
      sb.append(raw.substring(12, 16));
      sb.append("-");
      sb.append(raw.substring(16, 20));
      sb.append("-");
      sb.append(raw.substring(20));

return sb.toString();
}

   public void run(HttpPresentationComms comms)
   throws HttpPresentationException, IOException {
           guid myGUID = new guid();
     //     System.out.println("Seeding String=" + myGUID.valueBeforeMD5);
     //     System.out.println("rawGUID=" + myGUID.valueAfterMD5);"RandomGUID="
          System.out.println( myGUID.toString());

}

}

1.5版本以后加入了java.util.uuid;

直接这样好了

UUID uuid = UUID.randomUUID();
System.out.println("{"+uuid.toString()+"}");