springjdbc.zip_SpringJDBC_spring jdbc_spring 增删改查_springjdbc xml

package com.spring.jdbc.util; 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 RandomGUID { private String valueBeforeMD5 = ""; private 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 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 = new SecureRandom(); long secureInitializer = mySecureRand.nextLong(); myRand = new Random(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. */ public RandomGUID() { 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(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) { e.printStackTrace(); } 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); e.printStackTrace(); } } /* * 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 String getUUID() { return valueAfterMD5; } public String getUUID(boolean upper) { return upper ? valueAfterMD5.toUpperCase() : valueAfterMD5; } // Demonstraton and self test of class public static void main(String args[]) { for (int i = 0; i < 100; i++) { System.out.println(new RandomGUID().getUUID(true)); } } }