?UUID(Universally Unique Identifier)全局唯一標(biāo)識(shí)符,是指在一臺(tái)機(jī)器上生成的數(shù)字，它保證對(duì)在同一時(shí)空中的所有機(jī)器都是唯一的。按照開放軟件基金會(huì)(OSF)制定的標(biāo)準(zhǔn)計(jì)算，用到了以太網(wǎng)卡地址、納秒級(jí)時(shí)間、芯片ID碼和許多可能的數(shù)字。由以下幾部分的組合：當(dāng)前日期和時(shí)間(UUID的第一個(gè)部分與時(shí)間有關(guān)，如果你在生成一個(gè)UUID之后，過(guò)幾秒又生成一個(gè)UUID，則第一個(gè)部分不同，其余相同)，時(shí)鐘序列，全局唯一的IEEE機(jī)器識(shí)別號(hào)（如果有網(wǎng)卡，從網(wǎng)卡獲得，沒(méi)有網(wǎng)卡以其他方式獲得），UUID的唯一缺陷在于生成的結(jié)果串會(huì)比較長(zhǎng)。
在Java中生成UUID主要有以下幾種方式:
1. JDK1.5
如果使用的JDK1.5的話,那么生成UUID變成了一件簡(jiǎn)單的事,以為JDK實(shí)現(xiàn)了UUID: java.util.UUID,直接調(diào)用即可.
UUID uuid? =? UUID.randomUUID();
2. 第三方開源類庫(kù)(推薦使用):
最著名的是 JUG .特點(diǎn)上是: 純Java實(shí)現(xiàn)，開源，LGPL協(xié)議。采用了Native的方式產(chǎn)生真正的Uuid.而且提供了不同平臺(tái)的實(shí)現(xiàn),包括:
??? * Linux / x86
??? * Windows (98, ME, NT, 2K, XP?) / x86
??? * Solaris / Sparc
??? * Mac OS X
??? * FreeBSD / x86
import? org.doomdark.uuid.UUID;
import? org.doomdark.uuid.UUIDGenerator;
UUIDGenerator generator? =? UUIDGenerator.getInstance();
UUID uuid? =? generator.generateRandomBasedUUID();
3. Java代碼實(shí)現(xiàn):
如果你使用JDK1.4或以前版本,又不想加入第三方的類庫(kù)的話,下面提供了一個(gè)純Java的UUID實(shí)現(xiàn). 不過(guò)需要注意的是:這里產(chǎn)生的可能不是真正的UUID，只不過(guò)重復(fù)的機(jī)會(huì)少一些而已。
import? java.net.InetAddress;
import? java.net.UnknownHostException;
/** */ /**
?* UUID（Univeral Unique Identity）類
?*
?* Title: 生成唯一編碼
?*
?*
?* Description: 源自于w3c.org <</font>
http://源自于w3c.org >
?*
?*
?* Copyright: Copyright (c) 2001-2004
?*
?*
?*? @version? 1.0
? */
public?? final?? class? UUID? {
???? /** */ /**
???? *? @serial? Integer that helps create a unique UID.
????? */
???? private?? int? unique;
???? /** */ /**
???? *? @serial? Long used to record the time. The time will be
???? *???????? used to create a unique UID.
????? */
???? private?? long? time;
???? /** */ /**
???? * InetAddress to make the UID globally unique
????? */
???? private?? static? String address;
???? /** */ /**
???? * a random number
????? */
???? private?? static?? int? hostUnique;
???? /** */ /**
???? * Used for synchronization
????? */
???? private?? static? Object mutex;
???? private?? static?? long? lastTime;
???? private?? static?? long? DELAY;
???? private?? static? String generateNoNetworkID()? {
??????? Thread current? =? Thread.currentThread();
??????? String nid? =? current.activeCount()? +? System.getProperty( " os.version " )
???????????????? +? System.getProperty( " user.name? " )
???????????????? +? System.getProperty( " java.version " );
??????? System.out.println( " netWorkId = "?? +? nid);
??????? MD5 md5? =?? new? MD5(nid);
??????? md5.processString();
???????? return? md5.getStringDigest();
??? }
???? static?? {
??????? hostUnique? =? ( new? Object()).hashCode();
??????? mutex? =?? new? Object();
??????? lastTime? =? System.currentTimeMillis();
??????? DELAY? =?? 10 ;? //? in milliseconds
???????? try?? {
??????????? String s? =? InetAddress.getLocalHost().getHostAddress();
??????????? MD5 md5? =?? new? MD5(s);
??????????? md5.processString();
??????????? address? =? md5.getStringDigest();
??????? }?? catch? (UnknownHostException ex)? {
??????????? address? =? generateNoNetworkID();
??????? }
??? }
???? public? UUID()? {
???????? synchronized? (mutex)? {
???????????? boolean? done? =?? false ;
???????????? while? ( ! done)? {
??????????????? time? =? System.currentTimeMillis();
???????????????? if? (time?? lastTime? +? DELAY)? {
???????????????????? //? pause for a second to wait for time to change
???????????????????? try?? {
??????????????????????? Thread.currentThread().sleep(DELAY);
??????????????????? }?? catch? (java.lang.InterruptedException e)? {
??????????????????? }?? //? ignore exception
???????????????????? continue ;
??????????????? }?? else?? {
??????????????????? lastTime? =? time;
??????????????????? done? =?? true ;
??????????????? }
??????????? }
??????????? unique? =? hostUnique;
??????? }
??? }
???? public? String toString()? {
???????? return? Integer.toString(unique,? 16 )? +? Long.toString(time,? 16 )? +? address;
??? }
???? public?? boolean? equals(Object obj)? {
???????? if? ((obj? !=?? null )? &&? (obj? instanceof? UUID))? {
??????????? UUID uuid? =? (UUID) obj;
???????????? return? (unique? ==? uuid.unique? &&? time? ==? uuid.time? &&? address
??????????????????? .equals(uuid.address));
??????? }?? else?? {
???????????? return?? false ;
??????? }
??? }
???? public?? static?? void? main(String args[])? {
??????? System.out.println( new? UUID());
??????? System.out.println( new? UUID());
??????? System.out.println( new? UUID());
???????? long? start? =? System.currentTimeMillis();
??????? System.out.println( new? UUID());
???????? long? end? =? System.currentTimeMillis();
??????? System.out.println((end? -? start));
??????? System.out.println( new? UUID().toString().length());
??? }
???? /** */ /**
???? * 返回最新的UUID號(hào)碼
???? *
???? *? @return? String UUID，長(zhǎng)50位
???? *
????? */
???? public?? final?? static? String getUUID()? {
??????? UUID uid? =?? new? UUID();
???????? return? uid.toString();
??? }
}
其中使用到MD5加密算法,實(shí)現(xiàn)代碼如下:
import? java.io.ByteArrayInputStream;
import? java.io.File;
import? java.io.FileInputStream;
import? java.io.IOException;
import? java.io.InputStream;
import? java.io.UnsupportedEncodingException;
/** */ /**
?* MD5 加密算法類
?*
?*
?* Description: 源自于w3c.org <</font>
http://源自于w3c.org >
?*
?*
?* Copyright: Copyright (c) 2001-2004
?*
?*
?*? @version? 1.0
? */
public?? class? MD5? {
???? private?? static?? final?? int? BUFFER_SIZE? =?? 1024 ;
???? private?? static?? final?? int? S11? =?? 7 ;
???? private?? static?? final?? int? S12? =?? 12 ;
???? private?? static?? final?? int? S13? =?? 17 ;
???? private?? static?? final?? int? S14? =?? 22 ;
???? private?? static?? final?? int? S21? =?? 5 ;
???? private?? static?? final?? int? S22? =?? 9 ;
???? private?? static?? final?? int? S23? =?? 14 ;
???? private?? static?? final?? int? S24? =?? 20 ;
???? private?? static?? final?? int? S31? =?? 4 ;
???? private?? static?? final?? int? S32? =?? 11 ;
???? private?? static?? final?? int? S33? =?? 16 ;
???? private?? static?? final?? int? S34? =?? 23 ;
???? private?? static?? final?? int? S41? =?? 6 ;
???? private?? static?? final?? int? S42? =?? 10 ;
???? private?? static?? final?? int? S43? =?? 15 ;
???? private?? static?? final?? int? S44? =?? 21 ;
???? private?? static?? byte? padding[]? =?? { ( byte )? 0x80 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 , ( byte )? 0 ,
??????????? ( byte )? 0? } ;
???? private? InputStream in? =?? null ;
???? private?? boolean? stringp? =?? false ;
???? private?? int? state[]? =?? null ;
???? private?? long? count? =?? 0 ;
???? private?? byte? buffer[]? =?? null ;
???? private?? byte? digest[]? =?? null ;
???? private?? static? String stringify( byte? buf[])? {
??????? StringBuffer sb? =?? new? StringBuffer( 2?? *? buf.length);
???????? for? ( int? i? =?? 0 ; i?? buf.length; i ++ )? {
???????????? int? h? =? (buf[i]? &?? 0xf0 )? >>?? 4 ;
???????????? int? l? =? (buf[i]? &?? 0x0f );
??????????? sb.append( new? Character(( char ) ((h? >?? 9 )? ??? ' a '?? +? h? -?? 10? :? ' 0 '?? +? h)));
??????????? sb.append( new? Character(( char ) ((l? >?? 9 )? ??? ' a '?? +? l? -?? 10? :? ' 0 '?? +? l)));
??????? }
???????? return? sb.toString();
??? }
???? private?? final?? int? F( int? x,? int? y,? int? z)? {
???????? return? ((x? &? y)? |? (( ~ x)? &? z));
??? }
???? private?? final?? int? G( int? x,? int? y,? int? z)? {
???????? return? ((x? &? z)? |? (y? &? ( ~ z)));
??? }
???? private?? final?? int? H( int? x,? int? y,? int? z)? {
???????? return? (x? ^? y? ^? z);
??? }
???? private?? final?? int? I( int? x,? int? y,? int? z)? {
???????? return? (y? ^? (x? |? ( ~ z)));
??? }
???? private?? final?? int? rotate_left( int? x,? int? n)? {
???????? return? ((x? <<</span>? n) | (x >>> (32 -? n)));
??? }
???? private?? final?? int? FF( int? a,? int? b,? int? c,? int? d,? int? x,? int? s,? int? ac)? {
??????? a? +=? (F(b, c, d)? +? x? +? ac);
??????? a? =? rotate_left(a, s);
??????? a? +=? b;
???????? return? a;
??? }
???? private?? final?? int? GG( int? a,? int? b,? int? c,? int? d,? int? x,? int? s,? int? ac)? {
??????? a? +=? (G(b, c, d)? +? x? +? ac);
??????? a? =? rotate_left(a, s);
??????? a? +=? b;
???????? return? a;
??? }
???? private?? final?? int? HH( int? a,? int? b,? int? c,? int? d,? int? x,? int? s,? int? ac)? {
??????? a? +=? (H(b, c, d)? +? x? +? ac);
??????? a? =? rotate_left(a, s);
??????? a? +=? b;
???????? return? a;
??? }
???? private?? final?? int? II( int? a,? int? b,? int? c,? int? d,? int? x,? int? s,? int? ac)? {
??????? a? +=? (I(b, c, d)? +? x? +? ac);
??????? a? =? rotate_left(a, s);
??????? a? +=? b;
???????? return? a;
??? }
???? private?? final?? void? decode( int? output[],? byte? input[],? int? off,? int? len)? {
???????? int? i? =?? 0 ;
???????? int? j? =?? 0 ;
???????? for? (; j?? len; i ++ , j? +=?? 4 )? {
??????????? output[i]? =? ((( int ) (input[off? +? j]? &?? 0xff ))
???????????????????? |? ((( int ) (input[off? +? j? +?? 1 ]? &?? 0xff ))? <<</span>? 8 )
???????????????????? |? ((( int ) (input[off? +? j? +?? 2 ]? &?? 0xff ))? <<</span>? 16) | (((int ) (input[off
???????????????????? +? j? +?? 3 ]? &?? 0xff ))? <<</span>? 24 ));
??????? }
??? }
???? private?? final?? void? transform( byte? block[],? int? offset)? {
???????? int? a? =? state[ 0 ];
???????? int? b? =? state[ 1 ];
???????? int? c? =? state[ 2 ];
???????? int? d? =? state[ 3 ];
???????? int? x[]? =?? new?? int [ 16 ];
??????? decode(x, block, offset,? 64 );
???????? /**/ /*? Round 1? */
??????? a? =? FF(a, b, c, d, x[ 0 ], S11,? 0xd76aa478 );? /**/ /*? 1? */
??????? d? =? FF(d, a, b, c, x[ 1 ], S12,? 0xe8c7b756 );? /**/ /*? 2? */
??????? c? =? FF(c, d, a, b, x[ 2 ], S13,? 0x242070db );? /**/ /*? 3? */
??????? b? =? FF(b, c, d, a, x[ 3 ], S14,? 0xc1bdceee );? /**/ /*? 4? */
??????? a? =? FF(a, b, c, d, x[ 4 ], S11,? 0xf57c0faf );? /**/ /*? 5? */
??????? d? =? FF(d, a, b, c, x[ 5 ], S12,? 0x4787c62a );? /**/ /*? 6? */
??????? c? =? FF(c, d, a, b, x[ 6 ], S13,? 0xa8304613 );? /**/ /*? 7? */
??????? b? =? FF(b, c, d, a, x[ 7 ], S14,? 0xfd469501 );? /**/ /*? 8? */
??????? a? =? FF(a, b, c, d, x[ 8 ], S11,? 0x698098d8 );? /**/ /*? 9? */
??????? d? =? FF(d, a, b, c, x[ 9 ], S12,? 0x8b44f7af );? /**/ /*? 10? */
??????? c? =? FF(c, d, a, b, x[ 10 ], S13,? 0xffff5bb1 );? /**/ /*? 11? */
??????? b? =? FF(b, c, d, a, x[ 11 ], S14,? 0x895cd7be );? /**/ /*? 12? */
??????? a? =? FF(a, b, c, d, x[ 12 ], S11,? 0x6b901122 );? /**/ /*? 13? */
??????? d? =? FF(d, a, b, c, x[ 13 ], S12,? 0xfd987193 );? /**/ /*? 14? */
??????? c? =? FF(c, d, a, b, x[ 14 ], S13,? 0xa679438e );? /**/ /*? 15? */
??????? b? =? FF(b, c, d, a, x[ 15 ], S14,? 0x49b40821 );? /**/ /*? 16? */
???????? /**/ /*? Round 2? */
??????? a? =? GG(a, b, c, d, x[ 1 ], S21,? 0xf61e2562 );? /**/ /*? 17? */
??????? d? =? GG(d, a, b, c, x[ 6 ], S22,? 0xc040b340 );? /**/ /*? 18? */
??????? c? =? GG(c, d, a, b, x[ 11 ], S23,? 0x265e5a51 );? /**/ /*? 19? */
??????? b? =? GG(b, c, d, a, x[ 0 ], S24,? 0xe9b6c7aa );? /**/ /*? 20? */
??????? a? =? GG(a, b, c, d, x[ 5 ], S21,? 0xd62f105d );? /**/ /*? 21? */
??????? d? =? GG(d, a, b, c, x[ 10 ], S22,? 0x2441453 );? /**/ /*? 22? */
??????? c? =? GG(c, d, a, b, x[ 15 ], S23,? 0xd8a1e681 );? /**/ /*? 23? */
??????? b? =? GG(b, c, d, a, x[ 4 ], S24,? 0xe7d3fbc8 );? /**/ /*? 24? */
??????? a? =? GG(a, b, c, d, x[ 9 ], S21,? 0x21e1cde6 );? /**/ /*? 25? */
??????? d? =? GG(d, a, b, c, x[ 14 ], S22,? 0xc33707d6 );? /**/ /*? 26? */
??????? c? =? GG(c, d, a, b, x[ 3 ], S23,? 0xf4d50d87 );? /**/ /*? 27? */
??????? b? =? GG(b, c, d, a, x[ 8 ], S24,? 0x455a14ed );? /**/ /*? 28? */
??????? a? =? GG(a, b, c, d, x[ 13 ], S21,? 0xa9e3e905 );? /**/ /*? 29? */
??????? d? =? GG(d, a, b, c, x[ 2 ], S22,? 0xfcefa3f8 );? /**/ /*? 30? */
??????? c? =? GG(c, d, a, b, x[ 7 ], S23,? 0x676f02d9 );? /**/ /*? 31? */
??????? b? =? GG(b, c, d, a, x[ 12 ], S24,? 0x8d2a4c8a );? /**/ /*? 32? */
???????? /**/ /*? Round 3? */
??????? a? =? HH(a, b, c, d, x[ 5 ], S31,? 0xfffa3942 );? /**/ /*? 33? */
??????? d? =? HH(d, a, b, c, x[ 8 ], S32,? 0x8771f681 );? /**/ /*? 34? */
??????? c? =? HH(c, d, a, b, x[ 11 ], S33,? 0x6d9d6122 );? /**/ /*? 35? */
??????? b? =? HH(b, c, d, a, x[ 14 ], S34,? 0xfde5380c );? /**/ /*? 36? */
??????? a? =? HH(a, b, c, d, x[ 1 ], S31,? 0xa4beea44 );? /**/ /*? 37? */
??????? d? =? HH(d, a, b, c, x[ 4 ], S32,? 0x4bdecfa9 );? /**/ /*? 38? */
??????? c? =? HH(c, d, a, b, x[ 7 ], S33,? 0xf6bb4b60 );? /**/ /*? 39? */
??????? b? =? HH(b, c, d, a, x[ 10 ], S34,? 0xbebfbc70 );? /**/ /*? 40? */
??????? a? =? HH(a, b, c, d, x[ 13 ], S31,? 0x289b7ec6 );? /**/ /*? 41? */
??????? d? =? HH(d, a, b, c, x[ 0 ], S32,? 0xeaa127fa );? /**/ /*? 42? */
??????? c? =? HH(c, d, a, b, x[ 3 ], S33,? 0xd4ef3085 );? /**/ /*? 43? */
??????? b? =? HH(b, c, d, a, x[ 6 ], S34,? 0x4881d05 );? /**/ /*? 44? */
??????? a? =? HH(a, b, c, d, x[ 9 ], S31,? 0xd9d4d039 );? /**/ /*? 45? */
??????? d? =? HH(d, a, b, c, x[ 12 ], S32,? 0xe6db99e5 );? /**/ /*? 46? */
??????? c? =? HH(c, d, a, b, x[ 15 ], S33,? 0x1fa27cf8 );? /**/ /*? 47? */
??????? b? =? HH(b, c, d, a, x[ 2 ], S34,? 0xc4ac5665 );? /**/ /*? 48? */
???????? /**/ /*? Round 4? */
??????? a? =? II(a, b, c, d, x[ 0 ], S41,? 0xf4292244 );? /**/ /*? 49? */
??????? d? =? II(d, a, b, c, x[ 7 ], S42,? 0x432aff97 );? /**/ /*? 50? */
??????? c? =? II(c, d, a, b, x[ 14 ], S43,? 0xab9423a7 );? /**/ /*? 51? */
??????? b? =? II(b, c, d, a, x[ 5 ], S44,? 0xfc93a039 );? /**/ /*? 52? */
??????? a? =? II(a, b, c, d, x[ 12 ], S41,? 0x655b59c3 );? /**/ /*? 53? */
??????? d? =? II(d, a, b, c, x[ 3 ], S42,? 0x8f0ccc92 );? /**/ /*? 54? */
??????? c? =? II(c, d, a, b, x[ 10 ], S43,? 0xffeff47d );? /**/ /*? 55? */
??????? b? =? II(b, c, d, a, x[ 1 ], S44,? 0x85845dd1 );? /**/ /*? 56? */
??????? a? =? II(a, b, c, d, x[ 8 ], S41,? 0x6fa87e4f );? /**/ /*? 57? */
??????? d? =? II(d, a, b, c, x[ 15 ], S42,? 0xfe2ce6e0 );? /**/ /*? 58? */
??????? c? =? II(c, d, a, b, x[ 6 ], S43,? 0xa3014314 );? /**/ /*? 59? */
??????? b? =? II(b, c, d, a, x[ 13 ], S44,? 0x4e0811a1 );? /**/ /*? 60? */
??????? a? =? II(a, b, c, d, x[ 4 ], S41,? 0xf7537e82 );? /**/ /*? 61? */
??????? d? =? II(d, a, b, c, x[ 11 ], S42,? 0xbd3af235 );? /**/ /*? 62? */
??????? c? =? II(c, d, a, b, x[ 2 ], S43,? 0x2ad7d2bb );? /**/ /*? 63? */
??????? b? =? II(b, c, d, a, x[ 9 ], S44,? 0xeb86d391 );? /**/ /*? 64? */
??????? state[ 0 ]? +=? a;
??????? state[ 1 ]? +=? b;
??????? state[ 2 ]? +=? c;
??????? state[ 3 ]? +=? d;
??? }
???? private?? final?? void? update( byte? input[],? int? len)? {
???????? int? index? =? (( int ) (count? >>?? 3 ))? &?? 0x3f ;
??????? count? +=? (len? <<</span>? 3 );
???????? int? partLen? =?? 64?? -? index;
???????? int? i? =?? 0 ;
???????? if? (len? >=? partLen)? {
??????????? System.arraycopy(input,? 0 , buffer, index, partLen);
??????????? transform(buffer,? 0 );
???????????? for? (i? =? partLen; i? +?? 63??? len; i? +=?? 64 )
??????????????? transform(input, i);
??????????? index? =?? 0 ;
??????? }?? else?? {
??????????? i? =?? 0 ;
??????? }
??????? System.arraycopy(input, i, buffer, index, len? -? i);
??? }
???? private?? byte [] end()? {
???????? byte? bits[]? =?? new?? byte [ 8 ];
???????? for? ( int? i? =?? 0 ; i??? 8 ; i ++ )
??????????? bits[i]? =? ( byte ) ((count? >>>? (i? *?? 8 ))? &?? 0xff );
???????? int? index? =? (( int ) (count? >>?? 3 ))? &?? 0x3f ;
???????? int? padlen? =? (index??? 56 )? ?? ( 56?? -? index) : ( 120?? -? index);
??????? update(padding, padlen);
??????? update(bits,? 8 );
???????? return? encode(state,? 16 );
??? }
???? //? Encode the content.state array into 16 bytes array
???? private?? byte [] encode( int? input[],? int? len)? {
???????? byte? output[]? =?? new?? byte [len];
???????? int? i? =?? 0 ;
???????? int? j? =?? 0 ;
???????? for? (; j?? len; i ++ , j? +=?? 4 )? {
??????????? output[j]? =? ( byte ) ((input[i])? &?? 0xff );
??????????? output[j? +?? 1 ]? =? ( byte ) ((input[i]? >>?? 8 )? &?? 0xff );
??????????? output[j? +?? 2 ]? =? ( byte ) ((input[i]? >>?? 16 )? &?? 0xff );
??????????? output[j? +?? 3 ]? =? ( byte ) ((input[i]? >>?? 24 )? &?? 0xff );
??????? }
???????? return? output;
??? }
???? /** */ /**
???? * Get the digest for our input stream. This method constructs the input
???? * stream digest, and return it, as a a String, following the MD5 (rfc1321)
???? * algorithm,
???? *
???? *? @return? An instance of String, giving the message digest.
???? *? @exception? IOException
???? *??????????????? Thrown if the digestifier was unable to read the input
???? *??????????????? stream.
????? */
???? public?? byte [] getDigest()? throws? IOException? {
???????? byte? buffer[]? =?? new?? byte [BUFFER_SIZE];
???????? int? got? =?? - 1 ;
???????? if? (digest? !=?? null )
???????????? return? digest;
???????? while? ((got? =? in.read(buffer))? >?? 0 )
??????????? update(buffer, got);
???????? this .digest? =? end();
???????? return? digest;
??? }
???? /** */ /**
???? * Get the digest, for this string digestifier. This method doesn't throw
???? * any IOException, since it knows that the underlying stream ws built from
???? * a String.
????? */
???? public?? byte [] processString()? {
???????? if? ( ! stringp)
???????????? throw?? new? RuntimeException( this .getClass().getName()
???????????????????? +?? " [processString] "?? +?? "? not a string. " );
???????? try?? {
???????????? return? getDigest();
??????? }?? catch? (IOException ex)? {
??????? }
???????? throw?? new? RuntimeException( this .getClass().getName()
???????????????? +?? " [processString] "?? +?? " : implementation error. " );
??? }
???? /** */ /**
???? * Get the digest, as a proper string.
????? */
???? public? String getStringDigest()? {
???????? if? (digest? ==?? null )
???????????? throw?? new? RuntimeException( this .getClass().getName()
???????????????????? +?? " [getStringDigest] "?? +?? " : called before processing. " );
???????? return? stringify(digest);
??? }
???? /** */ /**
???? * Construct a digestifier for the given string.
???? *
???? *? @param? input
???? *??????????? The string to be digestified.
???? *? @param? encoding
???? *??????????? the encoding name used (such as UTF8)
????? */
???? public? MD5(String input, String enc)? {
???????? byte? bytes[]? =?? null ;
???????? try?? {
??????????? bytes? =? input.getBytes(enc);
??????? }?? catch? (UnsupportedEncodingException e)? {
???????????? throw?? new? RuntimeException( " no? "?? +? enc? +?? "? encoding!!! " );
??????? }
???????? this .stringp? =?? true ;
???????? this .in? =?? new? ByteArrayInputStream(bytes);
???????? this .state? =?? new?? int [ 4 ];
???????? this .buffer? =?? new?? byte [ 64 ];
???????? this .count? =?? 0 ;
??????? state[ 0 ]? =?? 0x67452301 ;
??????? state[ 1 ]? =?? 0xefcdab89 ;
??????? state[ 2 ]? =?? 0x98badcfe ;
??????? state[ 3 ]? =?? 0x10325476 ;
??? }
???? /** */ /**
???? * Construct a digestifier for the given string.
???? *
???? *? @param? input
???? *??????????? The string to be digestified.
????? */
???? public? MD5(String input)? {
???????? this (input,? " UTF8 " );
??? }
???? /** */ /**
???? * Construct a digestifier for the given input stream.
???? *
???? *? @param? in
???? *??????????? The input stream to be digestified.
????? */
???? public? MD5(InputStream in)? {
???????? this .stringp? =?? false ;
???????? this .in? =? in;
???????? this .state? =?? new?? int [ 4 ];
???????? this .buffer? =?? new?? byte [ 64 ];
???????? this .count? =?? 0 ;
??????? state[ 0 ]? =?? 0x67452301 ;
??????? state[ 1 ]? =?? 0xefcdab89 ;
??????? state[ 2 ]? =?? 0x98badcfe ;
??????? state[ 3 ]? =?? 0x10325476 ;
??? }
???? public?? static?? void? main(String args[])? throws? IOException? {
???????? if? (args.length? !=?? 1 )? {
??????????? System.out.println( " Md5? " );
??????????? System.exit( 1 );
??????? }
??????? MD5 md5? =?? new? MD5( new? FileInputStream( new? File(args[ 0 ])));
???????? byte? b[]? =? md5.getDigest();
??????? System.out.println(stringify(b));
??? }
}