package cn.flightfeather.thirdappmodule.util;
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import java.net.InetAddress;
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import java.security.SecureRandom;
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import java.util.UUID;
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/**
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* @author Felix.yu
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*/
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public class UUIDGenerator {
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private static SecureRandom seederStatic;
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private static byte addr[];
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private static String midValueStatic = null;
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private String midValue;
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private SecureRandom seeder;
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private static long prevMillis = 0L;
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private static byte addrBytes[] = null;
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static {
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seederStatic = null;
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addr = null;
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try {
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addr = InetAddress.getLocalHost().getAddress();
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addrBytes = InetAddress.getLocalHost().getAddress();
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StringBuffer buffer = new StringBuffer(8);
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buffer.append(toHex(toInt(addr), 8));
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midValueStatic = buffer.toString();
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seederStatic = new SecureRandom();
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seederStatic.nextInt();
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} catch (Exception ex) {
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}
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}
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public UUIDGenerator() {
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midValue = null;
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seeder = null;
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StringBuffer buffer = new StringBuffer(16);
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buffer.append(midValueStatic);
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buffer.append(toHex(System.identityHashCode(this), 8));
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midValue = buffer.toString();
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seeder = new SecureRandom();
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seeder.nextInt();
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}
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public static String generate(Object obj) {
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StringBuffer uid = new StringBuffer(32);
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long currentTimeMillis = System.currentTimeMillis();
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uid.append(toHex((int) (currentTimeMillis & -1L), 8));
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uid.append(midValueStatic);
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uid.append(toHex(System.identityHashCode(obj), 8));
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uid.append(toHex(getRandom(), 8));
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return uid.toString();
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}
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public static String generate16(Object obj) {
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StringBuffer uid = new StringBuffer(16);
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uid.append(toHex(System.identityHashCode(obj), 8));
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uid.append(toHex(getRandom(), 8));
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return uid.toString();
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}
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public String generate() {
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StringBuffer uid = new StringBuffer(32);
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long currentTimeMillis = System.currentTimeMillis();
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uid.append(toHex((int) (currentTimeMillis & -1L), 8));
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uid.append(midValue);
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uid.append(toHex(seeder.nextInt(), 8));
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return uid.toString();
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}
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private static String toHex(int value, int length) {
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char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
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'A', 'B', 'C', 'D', 'E', 'F'};
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StringBuffer buffer = new StringBuffer(length);
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int shift = length - 1 << 2;
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for (int i = -1; ++i < length; ) {
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buffer.append(hexDigits[value >> shift & 0xf]);
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value <<= 4;
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}
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return buffer.toString();
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}
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private static int toInt(byte bytes[]) {
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int value = 0;
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for (int i = -1; ++i < bytes.length; ) {
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value <<= 8;
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value |= bytes[i];
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}
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return value;
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}
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private static synchronized int getRandom() {
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return seederStatic.nextInt();
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}
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private static synchronized long getSystemTimeMillis() {
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long millis = System.currentTimeMillis();
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if (millis > prevMillis) {
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prevMillis = millis;
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} else {
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prevMillis++;
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}
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return prevMillis;
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}
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public static Long getUniqueLong() {
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long l = getSystemTimeMillis();
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l *= 1000L;
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long b1 = addrBytes[3] & 0xff;
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l += b1;
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return Long.valueOf(l);
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}
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public static String[] chars = new String[] { "a", "b", "c", "d", "e", "f",
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"g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s",
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"t", "u", "v", "w", "x", "y", "z", "0", "1", "2", "3", "4", "5",
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"6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H", "I",
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"J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V",
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"W", "X", "Y", "Z" };
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/*
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* 长度为8位的UUID
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*/
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public static String generateShortUUID() {
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StringBuffer shortBuffer = new StringBuffer();
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String uuid = UUID.randomUUID().toString().replace("-", "");
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for (int i = 0; i < 8; i++) {
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String str = uuid.substring(i * 4, i * 4 + 4);
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int x = Integer.parseInt(str, 16);
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shortBuffer.append(chars[x % 0x3E]);
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}
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return shortBuffer.toString();
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}
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/*
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* 长度为16位的UUID
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*/
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public static String generate16ShortUUID() {
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StringBuffer shortBuffer = new StringBuffer();
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String uuid = UUID.randomUUID().toString().replace("-", "");
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for (int i = 0; i < 16; i++) {
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String str = uuid.substring(i * 2, i * 2 + 2);
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int x = Integer.parseInt(str, 16);
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shortBuffer.append(chars[x % 0x3E]);
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}
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return shortBuffer.toString();
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}
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/**
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* 长度为指定位数的UUID
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* @param uuidLength
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* @return
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*/
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public static String generateUUID(int uuidLength) {
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StringBuffer shortBuffer = new StringBuffer();
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String uuid = UUID.randomUUID().toString().replace("-", "");
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for (int i = 0; i < uuidLength; i++) {
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String str = uuid.substring(i * 4, i * 4 + 4);
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int x = Integer.parseInt(str, 16);
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shortBuffer.append(chars[x % 0x3E]);
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}
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return shortBuffer.toString();
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}
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}
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