java uuid to long_JAVA UUID 生成

packagecom.utils;/*@authorAdministrator

*

* TODO To change the template for this generated type comment go to

* Window – Preferences – Java – Code Style – Code Templates*/

importjava.net.InetAddress;importjava.net.UnknownHostException;importjava.security.MessageDigest;importjava.security.NoSuchAlgorithmException;importjava.security.SecureRandom;importjava.util.Random;public class RandomGUID extendsObject {protected final org.apache.commons.logging.Log logger =org.apache.commons.logging.LogFactory

.getLog(getClass());public String valueBeforeMD5 = “”;public String valueAfterMD5 = “”;private staticRandom myRand;private staticSecureRandom mySecureRand;private staticString s_id;private static final int PAD_BELOW = 0x10;private static final int TWO_BYTES = 0xFF;/ Static block to take care of one time secureRandom seed.

* It takes a few seconds to initialize SecureRandom. You might

* want to consider removing this static block or replacing

* it with a “time since first loaded” seed to reduce this time.

* This block will run only once per JVM instance.*/

static{

mySecureRand= newSecureRandom();long secureInitializer =mySecureRand.nextLong();

myRand= newRandom(secureInitializer);try{

s_id=InetAddress.getLocalHost().toString();

}catch(UnknownHostException e) {

e.printStackTrace();

}

}/ Default constructor. With no specification of security option,

* this constructor defaults to lower security, high performance.*/

publicRandomGUID() {

getRandomGUID(false);

}/ Constructor with security option. Setting secure true

* enables each random number generated to be cryptographically

* strong. Secure false defaults to the standard Random function seeded

* with a single cryptographically strong random number.*/

public RandomGUID(booleansecure) {

getRandomGUID(secure);

}/ Method to generate the random GUID*/

private void getRandomGUID(booleansecure) {

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

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-11D1-8B05-00D9B6*/

publicString 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));returnsb.toString();

}//Demonstraton and self test of class

public static voidmain(String args[]) {for (int i=0; i< 1; i++) {

RandomGUID myGUID= newRandomGUID();

System.out.println(“Seeding String:\t” +myGUID.valueBeforeMD5);

System.out.println(“rawGUID:\t” +myGUID.valueAfterMD5);

System.out.println(“RandomGUID:\t” +myGUID.toString());

}

}

}