public class UniqId 
{
private static char[] digits = { '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
private static Map<Character, Integer> rDigits = new HashMap<Character, Integer>(
16);
static {
for (int i = 0; i < digits.length; ++i) {
rDigits.put(digits[i], i);
}
}
private static UniqId me = new UniqId();
private String hostAddr;
private Random random = new SecureRandom();
private MessageDigest mHasher;
private UniqTimer timer = new UniqTimer();
private ReentrantLock opLock = new ReentrantLock();
private UniqId() {
try {
InetAddress addr = InetAddress.getLocalHost();
hostAddr = addr.getHostAddress();
} catch (IOException e) {
hostAddr = String.valueOf(System.currentTimeMillis());
}
if (hostAddr == null || hostAddr.length() == 0
|| "127.0.0.1".equals(hostAddr)) {
hostAddr = String.valueOf(System.currentTimeMillis());
}
try {
mHasher = MessageDigest.getInstance("MD5");
} catch (NoSuchAlgorithmException nex) {
mHasher = null;
}
}
/** *//**
* 獲取UniqID實(shí)例
*
* @return UniqId
*/
public static UniqId getInstance() {
return me;
}
/** *//**
* 獲得不會(huì)重復(fù)的毫秒數(shù)
*
* @return
*/
public long getUniqTime() {
return timer.getCurrentTime();
}
/** *//**
* 獲得UniqId
*
* @return uniqTime-randomNum-hostAddr-threadId
*/
public String getUniqID() {
StringBuffer sb = new StringBuffer();
long t = timer.getCurrentTime();
sb.append(t);
sb.append("-");
sb.append(random.nextInt(8999) + 1000);
sb.append("-");
sb.append(hostAddr);
sb.append("-");
sb.append(Thread.currentThread().hashCode());
return sb.toString();
}
/** *//**
* 獲取MD5之后的uniqId string
*
* @return uniqId md5 string
*/
public String getUniqIDHashString() {
return hashString(getUniqID());
}
/** *//**
* 獲取MD5之后的uniqId
*
* @return byte[16]
*/
public byte[] getUniqIDHash() {
return hash(getUniqID());
}
/** *//**
* 對(duì)字符串進(jìn)行md5
*
* @param str
* @return md5 byte[16]
*/
public byte[] hash(String str) {
opLock.lock();
try {
byte[] bt = mHasher.digest(str.getBytes("UTF-8"));
if (null == bt || bt.length != 16) {
throw new IllegalArgumentException("md5 need");
}
return bt;
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("unsupported utf-8 encoding", e);
} finally {
opLock.unlock();
}
}
/** *//**
* 對(duì)二進(jìn)制數(shù)據(jù)進(jìn)行md5
*
* @param str
* @return md5 byte[16]
*/
public byte[] hash(byte[] data) {
opLock.lock();
try {
byte[] bt = mHasher.digest(data);
if (null == bt || bt.length != 16) {
throw new IllegalArgumentException("md5 need");
}
return bt;
} finally {
opLock.unlock();
}
}
/** *//**
* 對(duì)字符串進(jìn)行md5 string
*
* @param str
* @return md5 string
*/
public String hashString(String str) {
byte[] bt = hash(str);
return bytes2string(bt);
}
/** *//**
* 對(duì)字節(jié)流進(jìn)行md5 string
*
* @param str
* @return md5 string
*/
public String hashBytes(byte[] str) {
byte[] bt = hash(str);
return bytes2string(bt);
}
/** *//**
* 將一個(gè)字節(jié)數(shù)組轉(zhuǎn)化為可見(jiàn)的字符串
*
* @param bt
* @return
*/
public String bytes2string(byte[] bt) {
int l = bt.length;
char[] out = new char[l << 1];
for (int i = 0, j = 0; i < l; i++) {
out[j++] = digits[(0xF0 & bt[i]) >>> 4];
out[j++] = digits[0x0F & bt[i]];
}
return new String(out);
}
/** *//**
* 將字符串轉(zhuǎn)換為bytes
*
* @param str
* @return byte[]
*/
public byte[] string2bytes(String str) {
if (null == str) {
throw new NullPointerException("參數(shù)不能為空");
}
if (str.length() != 32) {
throw new IllegalArgumentException("字符串長(zhǎng)度必須是32");
}
byte[] data = new byte[16];
char[] chs = str.toCharArray();
for (int i = 0; i < 16; ++i) {
int h = rDigits.get(chs[i * 2]).intValue();
int l = rDigits.get(chs[i * 2 + 1]).intValue();
data[i] = (byte) ((h & 0x0F) << 4 | (l & 0x0F));
}
return data;
}
/** *//**
* 實(shí)現(xiàn)不重復(fù)的時(shí)間
*
* @author dogun
*/
private static class UniqTimer {
private AtomicLong lastTime = new AtomicLong(System.currentTimeMillis());
public long getCurrentTime() {
return this.lastTime.incrementAndGet();
}
}
}
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