½W?5 天的问题
下é¢çš„程åºæ˜¯å¯¹ä¸¤ä¸ªåå…è¿›åˆÓž¼ˆhexåQ‰å—é¢å¸¸é‡è¿›è¡Œç›¸åŠ ，然åŽæ‰“å°å‡ºåå…进制的¾l“果。这个程åºä¼š(x¨¬)打å°å‡ÞZ»€ä¹ˆå‘¢åQ?/p>
public class JoyOfHex {
public static void main(String[] args) {
System.out.println(Long.toHexString(0x100000000L + 0xcafebabe));
}
}
½W?5 天问题的解ç”
看è“væ¥å¾ˆæ˜Žæ˜¾åQŒè¯¥½E‹åºåº”该打å°å‡?cafebabe。毕竟，˜q™ç¡®å®žå°±æ˜¯åå…进制数å?0000000016与cafebabe16的和。该½E‹åºä½¿ç”¨çš„是long型追Ž—，它å¯ä»¥æ”¯æŒ?6ä½åå…进制数åQŒå› æ¤è¿½Ž—溢出是ä¸å¯èƒ½çš„ã€?/p>
é—æ†¾çš„å‘Šè¯‰ä½ åQŒç»“果是cafebabeåQŒåƈ没有ä»ÖM½•å‰å¯¼çš?。这个输å‡?gu¨®)™¡¨½Cºçš„是棼‹®ç»“果的ä½?2ä½ï¼Œä½†æ˜¯ä¸çŸ¥ä½•æ•…åQŒç¬¬33ä½ä¸¢å¤×ƒº†(ji¨£n)ã€?/p>
原å›
å进制å—é¢å¸¸é‡å…·æœ‰ä¸€ä¸ªå¾ˆå¥½çš„属性，åÏx(ch¨®ng)‰€æœ‰çš„å进制å—é¢å¸¸é‡éƒ½æ˜¯æ£çš„，而åå…进制或是八˜q›åˆ¶å—é¢å¸”R‡òq¶ä¸å…·å¤‡˜q™ä¸ªå±žæ€§ã€?/p>
è¦æƒ³ä¹¦å†™ä¸€ä¸ªè´Ÿçš„å˜q›åˆ¶å¸”R‡åQŒå¯ä»¥ä‹É用一元å–åæ“作符åQ?åQ‰è¿žæŽ¥ä¸€ä¸ªå˜q›åˆ¶å—é¢å¸”R‡ã€‚以˜q™ç§æ–¹å¼åQŒä½ å¯ä»¥ç”¨å˜q›åˆ¶æ¥ä¹¦å†™ä“Q何int或longåž‹çš„æ•°å€û|¼Œä¸ç®¡å®ƒæ˜¯æ£çš„˜q˜æ˜¯è´Ÿçš„åQŒåƈ且负的å˜q›åˆ¶å¸¸æ•°å¯ä»¥å¾ˆæ˜Ž¼‹®åœ°ç”¨ä¸€ä¸ªå‡åïL(f¨¥ng)¬¦åäh¥æ ‡è¯†ã€?/p>
但是åå…˜q›åˆ¶å’Œå…«˜q›åˆ¶å—é¢å¸”R‡òq¶ä¸æ˜¯è¿™ä¹ˆå›žäº‹ï¼Œå®ƒä»¬å¯ä»¥å…ähœ‰æ£çš„以åŠ(qi¨¢ng)负的数倹{€‚如果åå…进制和八进制å—é¢å¸¸é‡çš„最高ä(sh¨´)½è¢«ç½®ä½äº†(ji¨£n)åQŒé‚£ä¹ˆå®ƒä»¬å°±æ˜¯è´Ÿæ•°ã€‚在˜q™ä¸ª½E‹åºä¸ï¼Œæ•°å—0xcafebabe是一个int帔R‡åQŒå®ƒçš„最高ä(sh¨´)½è¢«ç½®ä½äº†(ji¨£n)åQŒæ‰€ä»¥å®ƒæ˜¯ä¸€ä¸ªè´Ÿæ•°ã€‚它½{‰äºŽå进制数å€?889275714ã€?/p>
该程åºæ‰§è¡Œçš„˜q™ä¸ªåŠ 法是一¿U?混刾cÕdž‹çš„计½Ž—（mixed-type computationåQ‰ã€‚å·¦æ“作数是 long ¾cÕdž‹çš„，而å³æ“作数是 int ¾cÕdž‹çš„。äØ“(f¨´)äº?ji¨£n)执行该计算åQŒJavaž®†int¾cÕdž‹çš„数值用拓宽原始¾cÕdž‹è½¬æ¢æå‡ä¸ÞZ¸€ä¸ªlong¾cÕdž‹åQŒç„¶åŽå¯¹ä¸¤ä¸ªlong¾cÕdž‹æ•°å€¼ç›¸åŠ ã€‚å› ä¸ºint是一个有½W¦å·çš„整数类型，所以这个è{æ¢æ‰§è¡Œçš„是符åˆæ‰©å±•ï¼Œå®ƒå°†è´Ÿçš„int¾cÕdž‹çš„数值æå‡äØ“(f¨´)一个在数å€ég¸Šç›¸ç‰çš„long¾cÕdž‹æ•°å€¹{€?/p>
解决办法
System.out.println(Long.toHexString(0x100000000L + 0xcafebabeL));
˜q™ä¸ªåŠ 法的å³æ“作æ•?xcafebabe被æå‡äØ“(f¨´)äº?ji¨£n)long¾cÕdž‹çš„æ•°å€?xffffffffcafebabeL。这个数å€ég¹‹åŽè¢«åŠ 到äº?ji¨£n)å·¦æ“作æ?x100000000L上。当作äØ“(f¨´)int¾cÕdž‹æ¥è¢«å®¡è§†æ—Óž¼Œ¾l过½W¦å·æ‰©å±•ä¹‹åŽçš„å³æ“作数的é«?2ä½æ˜¯-1åQŒè€Œå·¦æ“作数的é«?2ä½æ˜¯1åQŒå°†˜q™ä¸¤ä¸ªæ•°å€¼ç›¸åŠ 就得到äº?åQŒè¿™ä¹Ÿå°±è§£é‡Šäº?ji¨£n)äØ?f¨´)什么在½E‹åºè¾“出ä¸å‰å¯?丢失äº?ji¨£n)ã€?/p>
½W?5 天问题的æ€È»“
˜q™ä¸ªé¢˜ç»™æˆ‘们的教è®æ˜¯åQ?strong>混刾cÕdž‹çš„计½Ž—å¯èƒ½ä¼š(x¨¬)产生æ·äh·†åQŒå°¤å…¶æ˜¯åå…˜q›åˆ¶å’Œå…«˜q›åˆ¶å—é¢å¸”R‡æ— 需昑ּ的å‡åïL(f¨¥ng)¬¦å·å°±å¯ä»¥è¡¨ç¤ºè´Ÿçš„数倹{€‚äØ“(f¨´)äº?ji¨£n)é¿å…è¿™¿U窘境，通常最好是é¿å…混刾cÕdž‹çš„计½Ž?/strong>ã€?/p>
对于è¯è¨€çš„设计者们æ¥è¯´åQŒåº”该考虑支æŒæ— 符åïL(f¨¥ng)š„æ•´æ•°¾cÕdž‹åQŒä»Žè€Œæ ¹é™¤ç¬¦åäh‰©å±•çš„å¯èƒ½æ€§ã€‚å¯èƒ½ä¼š(x¨¬)有这æ ïL(f¨¥ng)š„争辩åQšè´Ÿçš„åå…进制和八进制å—é¢å¸¸é‡åº”该被¼›ç”¨åQŒä½†æ˜¯è¿™å¯èƒ½ä¼?x¨¬)挫伤程åºå‘˜åQŒä»–们ç»å¸æ€‹É用åå…进制å—é¢å¸¸é‡æ¥è¡¨ç¤ºé‚£äº›½W¦å·æ²¡æœ‰ä»ÖM½•é‡è¦å«ä¹‰çš„数倹{€?/p>
今天的问�/h2>
转型被用æ¥å°†ä¸€ä¸ªæ•°å€ég»Žä¸€¿U类型è{æ¢åˆ°å¦ä¸€¿U类型。下é¢çš„½E‹åº˜qžç®‹(hu¨¤)使用äº?ji¨£n)三个è{型。那么它到底ä¼?x¨¬)打å°å‡ºä»€ä¹ˆå‘¢åQ?/p>
public class Multicast {
public static void main(String[] args) {
System.out.println((int) (char) (byte) -1);
}
}
]]>- ½W?5 天：(x¨¬) è§£ç” -- çœÆDŠ±¾~äØ•åQ?问题 -- 16˜q›åˆ¶çš„趣äº?/title><link>http://www.aygfsteel.com/fourlee/archive/2008/05/17/201025.html</link><dc:creator>æŽå››é£žåˆ€</dc:creator><author>æŽå››é£žåˆ€</author><pubDate>Fri, 16 May 2008 16:33:00 GMT</pubDate><guid>http://www.aygfsteel.com/fourlee/archive/2008/05/17/201025.html</guid><wfw:comment>http://www.aygfsteel.com/fourlee/comments/201025.html</wfw:comment><comments>http://www.aygfsteel.com/fourlee/archive/2008/05/17/201025.html#Feedback</comments><slash:comments>2</slash:comments><wfw:commentRss>http://www.aygfsteel.com/fourlee/comments/commentRss/201025.html</wfw:commentRss><trackback:ping>http://www.aygfsteel.com/fourlee/services/trackbacks/201025.html</trackback:ping><description><![CDATA[
<h2>½W?4 天的问题 -- çœÆDŠ±¾~äØ•</h2>
<p>它åˆä¼?x¨¬)打å°å‡ºä»€ä¹ˆå‘¢åQ?/p>
<pre>
<code class="java">
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">class</span> <span id="wmqeeuq" class="title">Elementary</span>{
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">void</span> main(String[] args){
System.out.println(<span id="wmqeeuq" class="number">12345</span> + <span id="wmqeeuq" class="number">5432</span>l);
}
}
</code>
</pre>
<h2>½W?4 天问题的解ç”</h2>
<p>˜q™ä¸ªé¢˜çœ‹èµäh¥ä¼ég¹Žå¤ªç®€å•äº†(ji¨£n)。结果丞®±æ˜¯66666å—？</p>
<p>é—æ†¾çš„å‘Šè¯‰ä½ åQŒç»“果是17777ã€?/p>
<h3>åŽŸå› </h3>
<p>事物往往有别于它的表象。就以这个问题ä(sh¨´)Ø“(f¨´)例，它åƈ没有打å°å‡ºæˆ‘们想è¦çš„输出。请仔细观察 + æ“作½W¦çš„两个æ“作敎ͼŒ 我们是将一个int¾cÕdž‹çš?2345åŠ åˆ°äº?ji¨£n)long¾cÕdž‹çš?432l上。请注æ„å·¦æ“作数开头的数å—1å’Œå³æ“作数结ž®„¡š„ž®å†™å—æ¯l之间的细微差异ã€?æ•°å—1çš„æ°´òq³ç¬”划（¿UîCØ“(f¨´)"臂（armåQ?åQ‰å’Œåž‚ç›´½W”划åQˆç§°ä¸?茎（stemåQ?åQ‰ä¹‹é—´æ˜¯ä¸€ä¸ªé”角，而与æ¤ç›¸å¯¹ç…§çš„是åQŒå°å†™å—æ¯l的臂和茎之间是一个直角ã€?/p>
<h3>解决办法</h3>
<pre>
<code class="java">System.out.println(<span id="wmqeeuq" class="number">12345</span>+<span id="wmqeeuq" class="number">5432</span>L);</code>
</pre>
<p>用大写的L替梞®å†™å—æ¯lã€?/p>
<h2>½W?4 天问题的æ€È»“</h2>
<p>åœ¨ä½ å¤§å–Š"æ¶å¿ƒ(j¨©)åQ?之å‰åQŒä½ 应该注æ„到这个问题确实已¾l引起了(ji¨£n)æ··äØ•åQŒè¿™é‡Œç¡®å®žæœ‰ä¸€ä¸ªæ•™è®ï¼š(x¨¬) <strong>在longåž‹å—é¢å¸¸é‡ä¸åQŒä¸€å®šè¦ç”¨å¤§å†™çš„LåQŒåƒä¸‡ä¸è¦ç”¨ž®å†™çš„l</strong>ã€‚è¿™æ ·å°±å¯ä»¥å®Œå…¨æŽæ–˜q™ä¸ªè°œé¢˜æ‰€äº§ç”Ÿçš„æØœä¹Þqš„æºå¤´ã€?/p>
<p>相类似的åQŒè¦é¿å…使用å•ç‹¬çš„一个lå—æ¯ä½œäØ“(f¨´)å˜é‡å。例如，我们很难通过观察下é¢çš„代ç 段æ¥åˆ¤æ–它到底是打å°å‡ºåˆ—表l˜q˜æ˜¯æ•°å—1ã€?/p>
<pre>
<code class="java"><span id="wmqeeuq" class="comment">//ä¸è‰¯ä»£ç -使用äº?ji¨£n)l作äØ“(f¨´)å˜é‡å?/span>
List l = <span id="wmqeeuq" class="keyword">new</span> ArrayList<String>();
l.add(<span id="wmqeeuq" class="string">"Foo"</span>);
System.out.println(<span id="wmqeeuq" class="number">1</span>);</code>
</pre>
<p>也许当åˆå…许用å°å†™çš„læ¥ç¼–写longåž‹å—é¢å¸¸é‡æœ¬íw«å°±æ˜¯ä¸€ä¸ªé”™è¯¯ã€?/p>
<hr id="hr"/>
<h2>今天的问�/h2>
<p>下é¢çš„程åºæ˜¯å¯¹ä¸¤ä¸ªåå…è¿›åˆÓž¼ˆhexåQ‰å—é¢å¸¸é‡è¿›è¡Œç›¸åŠ ，然åŽæ‰“å°å‡ºåå…进制的¾l“果。这个程åºä¼š(x¨¬)打å°å‡ÞZ»€ä¹ˆå‘¢åQ?/p>
<pre>
<code class="java"><span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="class"><span id="wmqeeuq" class="keyword">class</span> <span id="wmqeeuq" class="title">JoyOfHex</span> {</span>
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">void</span> main(String[] args) {
System.out.println(Long.toHexString(<span id="wmqeeuq" class="number">0x100000000L</span> + <span id="wmqeeuq" class="number">0xcafebabe</span>));
}
}</code>
</pre>
<img src ="http://www.aygfsteel.com/fourlee/aggbug/201025.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.aygfsteel.com/fourlee/" target="_blank">æŽå››é£žåˆ€</a> 2008-05-17 00:33 <a href="http://www.aygfsteel.com/fourlee/archive/2008/05/17/201025.html#Feedback" target="_blank" style="text-decoration:none;">å‘表评论</a></div>]]></description></item><item><title>½W?4 天：(x¨¬) è§£ç” -- 长整敎ͼŒ 问题 -- çœÆDŠ±¾~äØ•http://www.aygfsteel.com/fourlee/archive/2008/05/16/201018.htmlæŽå››é£žåˆ€æŽå››é£žåˆ€Fri, 16 May 2008 15:41:00 GMThttp://www.aygfsteel.com/fourlee/archive/2008/05/16/201018.htmlhttp://www.aygfsteel.com/fourlee/comments/201018.htmlhttp://www.aygfsteel.com/fourlee/archive/2008/05/16/201018.html#Feedback1http://www.aygfsteel.com/fourlee/comments/commentRss/201018.htmlhttp://www.aygfsteel.com/fourlee/services/trackbacks/201018.html½W?3 天的问题
被除数表½Cºçš„是一天里的微¿U’æ•°åQ›è€Œé™¤æ•°è¡¨½Cºçš„是一天里的毫¿U’数。这个程åºä¼š(x¨¬)打å°å‡ÞZ»€ä¹ˆå‘¢åQ?/p>
public class LongDivision{
public static void main(String args[]){
final long MICROS_PER_DAY = 24 * 60 * 60 * 1000 * 1000;
final long MILLIS_PER_DAY = 24 * 60 * 60 * 1000;
System.out.println(MICROS_PER_DAY/MILLIS_PER_DAY);
}
}
½W?3 天问题的解ç”
˜q™ä¸ªé¢˜çœ‹èµäh¥ç›¸å½“直观。æ¯å¤©çš„毫秒数和æ¯å¤©çš„å¾®¿U’数都是帔R‡ã€‚äØ“(f¨´)清楚赯‚§åQŒå®ƒä»¬éƒ½è¢«è¡¨½Cºæˆ¿U¯çš„å½¢å¼ã€‚ä½ å¯èƒ½æƒ³éƒ½æ²¡æƒ³åQŒå°±è„±å£è€Œå‡ºåQŒç»“果是1000ã€?é—憾的是åQŒå®ƒæ‰“å°çš„是5。这里到底å‘生了(ji¨£n)什么呢åQ?/p>
原å›
问题在于常数MICROS_PER_DAY的计½Ž?¼‹®å®ž"溢出äº?ji¨£n)。尽½Ž¡è®¡½Ž—çš„¾l“果适åˆæ”‘Ö…¥longä¸ï¼Œòq¶ä¸”其空间还有富余，但是˜q™ä¸ª¾l“æžœòq¶ä¸é€‚åˆæ”‘Ö…¥intä¸ã€?˜q™ä¸ªè®¡ç®—完全是以int˜qç®—æ¥æ‰§è¡Œçš„åQŒåƈ且åªæœ‰åœ¨˜q算完æˆä¹‹åŽåQŒå…¶¾l“æžœæ‰è¢«æå‡åˆ°l(f¨¡)ongåQŒè€Œæ¤æ—¶å·²¾l太˜qŸäº†(ji¨£n)åQšè®¡½Ž—å·²¾l溢å‡ÞZº†(ji¨£n)åQ?它返回的是一个å°äº?00å€çš„数倹{€‚从intæå‡åˆ°l(f¨¡)ong是一¿U拓宽原始类型è{æ¢ï¼ˆwidening primitive conversionåQ‰ï¼Œ 它ä¿ç•™äº†(ji¨£n)åQˆä¸æ£ç¡®çš„）(j¨ª)数倹{€‚这个å€ég¹‹åŽè¢«MILLIS_PER_DAY整除åQŒè€ŒMILLIS_PER_DAY的计½Ž—是æ£ç¡®çš„ï¼Œå› äØ“(f¨´)它适åˆint˜q算。这æ äh•´é™¤çš„¾l“æžœž®±å¾—åˆîCº†(ji¨£n)5
那么ä¸ÞZ»€ä¹ˆè®¡½Ž—会(x¨¬)是以int˜qç®—æ¥æ‰§è¡Œçš„å‘¢ï¼Ÿå› äØ“(f¨´)所有乘在一èµïL(f¨¥ng)š„å› å都是int数倹{€‚å½“ä½ å°†ä¸¤ä¸ªint数值相乘时åQ?ä½ å°†å¾—åˆ°å¦ä¸€ä¸ªint数倹{€?strong>Javaä¸å…·æœ‰ç›®æ ‡ç¡®å®šç±»åž‹çš„ç‰ÒŽ(gu¨©)€§ï¼Œ˜q™æ˜¯ä¸€¿Uè¯a€ç‰ÒŽ(gu¨©)€§ï¼Œå…¶å«ä¹‰æ˜¯æŒ‡å˜å‚¨ç»“果的å˜é‡çš„类型会(x¨¬)å½±å“到计½Ž—所使用的类åž?/strong>
解决办法
public class LongDivision{
public static void main(String args[ ]){
final long MICROS_PER_DAY = 24L * 60 * 60 * 1000 * 1000;
final long MILLIS_PER_DAY = 24L * 60 * 60 * 1000;
System.out.println(MICROS_PER_DAY/MILLIS_PER_DAY);
}
}
通过使用long帔R‡æ¥æ›¿ä»£int帔R‡ä½œäØ“(f¨´)æ¯ä¸€ä¸ªä¹˜¿U¯çš„½W¬ä¸€ä¸ªå› å，我们ž®±å¯ä»¥å¾ˆå®ÒŽ(gu¨©)˜“地订æ£è¿™ä¸ªç¨‹åºã€‚è¿™æ ·åšå¯ä»¥å¼ºåˆ¶è¡¨è¾¾å¼ä¸æ‰€æœ‰çš„åŽç®‹(hu¨¤)计算都用long˜q作æ¥å®Œæˆã€?ž®½ç®¡˜q™ä¹ˆåšåªåœ¨MICROS_PER_DAY表达å¼ä¸æ˜¯å¿…需的，但是在两个乘¿U¯ä¸éƒ½è¿™ä¹ˆåšæ˜¯ä¸€¿U很好的方å¼ã€‚相似地åQŒä‹É用long作äØ“(f¨´)乘积çš?½W¬ä¸€ä¸?æ•°å€ég¹Ÿòq¶ä¸æ€ÀL˜¯å¿…需的， 但是˜q™ä¹ˆåšä¹Ÿæ˜¯ä¸€¿U很好的形å¼ã€‚在两个计算ä¸éƒ½ä»¥long数值开始å¯ä»¥å¾ˆæ¸…楚地表明它们都ä¸ä¼š(x¨¬)溢出。下é¢çš„½E‹åºž®†æ‰“å°å‡ºæˆ‘们所期望çš?000
½W?3 天问题的æ€È»“
˜q™ä¸ªæ•™è®å¾ˆç®€å•ï¼š(x¨¬)å½“ä½ åœ¨æ“作很大的数å—æ—Óž¼Œåƒä¸‡è¦æ防溢å‡?/strong>--它å¯æ˜¯ä¸€ä¸ªç¼„默æ€æ‰‹ã€?å³ä‹É用æ¥ä¿å˜¾l“果的å˜é‡å·²æ˜‘Ö¾—‘›_¤Ÿå¤§ï¼Œä¹Ÿåƈä¸æ„味ç€è¦äñ”生结果的计算å…ähœ‰æ£ç¡®çš„ç±»åž‹ã€‚å½“ä½ æ‹¿ä¸å‡†æ—Óž¼Œž®×ƒ‹É用long˜qç®—æ¥æ‰§è¡Œæ•´ä¸ªè®¡½Ž—ã€?/p>
è¯è¨€è®¾è®¡è€…从ä¸å¯ä»¥å¸å–çš„æ•™è®æ˜¯ï¼š(x¨¬)也许é™ä½Ž¾~„默溢出产生的å¯èƒ½æ€§ç¡®å®žæ˜¯å€¼å¾—åšçš„一件事。这å¯ä»¥é€šè¿‡å¯¹ä¸ä¼?x¨¬)äñ”生缄默溢出的˜qç®—æ供支æŒæ¥å®žçŽ°ã€?½E‹åºå¯ä»¥æŠ›å‡ºä¸€ä¸ªå¼‚常而ä¸æ˜¯ç›´æŽ¥æº¢å‡ºï¼Œž®±åƒAdaæ‰€ä½œçš„é‚£æ ·åQŒæˆ–者它们å¯ä»¥åœ¨éœ€è¦çš„时候自动地切æ¢åˆîC¸€ä¸ªæ›´å¤§çš„内部表示上以防æ¢æº¢å‡ºåQŒå°±åƒLispæ‰€ä½œçš„é‚£æ ·ã€?˜q™ä¸¤¿Uæ–¹å¼éƒ½å¯èƒ½ä¼?x¨¬)éå—与其相关的性能斚w¢çš„æŸå¤±ã€?é™ä½Ž¾~„默溢出的å¦ä¸€¿Uæ–¹å¼æ˜¯æ”¯æŒç›®æ ‡¼‹®å®š¾cÕdž‹åQŒä½†æ˜¯è¿™ä¹ˆåšä¼?x¨¬)æ˜¾è‘—åœ°å¢žåŠ ¾cÕdž‹¾pÈ»Ÿçš„å¤æ‚度
今天的问�/h2>
它åˆä¼?x¨¬)打å°å‡ºä»€ä¹ˆå‘¢åQ?/p>
public class Elementary{
public static void main(String[] args){
System.out.println(12345+5432l);
}
}
]]>- ½W?3 天：(x¨¬) è§£ç” -- æ‰ùN›¶é’±ï¼Œ 问题 -- é•¿æ•´æ•?/title><link>http://www.aygfsteel.com/fourlee/archive/2008/05/16/201016.html</link><dc:creator>æŽå››é£žåˆ€</dc:creator><author>æŽå››é£žåˆ€</author><pubDate>Fri, 16 May 2008 14:50:00 GMT</pubDate><guid>http://www.aygfsteel.com/fourlee/archive/2008/05/16/201016.html</guid><wfw:comment>http://www.aygfsteel.com/fourlee/comments/201016.html</wfw:comment><comments>http://www.aygfsteel.com/fourlee/archive/2008/05/16/201016.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://www.aygfsteel.com/fourlee/comments/commentRss/201016.html</wfw:commentRss><trackback:ping>http://www.aygfsteel.com/fourlee/services/trackbacks/201016.html</trackback:ping><description><![CDATA[
<h2>½W?2 天的问题</h2>
<p>误‚€(g¨¨)ƒè™‘下题q™æ®µè¯æ‰€æ述的问题：(x¨¬)</p>
<p>ž®æ˜Žåœ¨è¶…å¸?j¨¬ng)è´ä¹îCº†(ji¨£n)一个äh(hu¨¢n)å€û|òE1.10的东西，但是他钱包ä¸åªæœ‰ä¸¤å…ƒä¸€å¼ çš„é’žç¥¨ã€‚å¦‚æžœä»–ç”¨ä¸€å¼ ä¸¤å…ƒçš„é’žç¥¨æ”¯ä»˜åQŒé‚£ä¹ˆåº”该找¾l™ä»–多少雉™’±å‘¢ï¼Ÿ</p>
<p>下é¢æ˜¯ä¸€ä¸ªè¯•å›¾è§£å†³ä¸Š˜q°é—®é¢˜çš„½E‹åºåQŒå®ƒä¼?x¨¬)打å°å‡ºä»€ä¹ˆå‘¢åQ?/p>
<pre>
<code class="java">
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">class</span> <span id="wmqeeuq" class="title">Change</span>{
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">void</span> main(String args[]){
System.out.println(<span id="wmqeeuq" class="number">2.00</span> - <span id="wmqeeuq" class="number">1.10</span>);
}
}
</code>
</pre>
<h2>½W?2 天问题的解ç”</h2>
<p>ä½ å¯èƒ½ä¼š(x¨¬)è¯ß_(d¨¢)¼Œ˜q™ä¸æ˜¯å¾ˆ½Ž€å•å˜›åQ输å‡?.90。但实际的输出确实：(x¨¬)0.8999999999999999ã€?/p>
<h3>åŽŸå› </h3>
<p>一ã€ç¨‹åºå¦‚何æ‰èƒ½çŸ¥é“ä½ æƒŒ™¦æ‰“å°ž®æ•°ç‚¹åŽä¸¤ä½ž®æ•°å‘¢ï¼Ÿ</p>
<p>JDK API文档ä¸å…³äºŽDouble.toString的部分指出：(x¨¬)</p>
<blockquote>
<p>Double.toString的返回å€û|¼Œæ˜¯èƒö以将double¾cÕdž‹çš„å€ég¸Žæœ€é 近它的临近值区分出æ¥çš„最çŸçš„ž®æ•°åQŒå®ƒåœ¨å°æ•°ç‚¹ä¹‹å‰å’Œä¹‹åŽéƒ½è‡›_°‘有一ä½ã€?/p>
</blockquote>
<p>å› æ¤åQŒçœ‹èµäh¥åQŒè¯¥½E‹åºåº”该打å°0.9是åˆç†çš„ã€?/p>
<p>二ã€åƈä¸æ˜¯æ‰€æœ‰çš„ž®æ•°éƒ½å¯ä»¥ç”¨äºŒè¿›åˆ¶æÕQç‚ÒŽ(gu¨©)•°æ¥ç²¾¼‹®è¡¨½Cºçš„ã€?/p>
<p>问题在于1.1˜q™ä¸ªæ•°å—ä¸èƒ½è¢«ç²¾¼‹®è¡¨½Cºæˆä¸ÞZ¸€ä¸ªdoubleåQŒå› æ¤å®ƒè¢«è¡¨½Cºæˆä¸ºæœ€æŽ¥è¿‘它的double倹{€?该程åºä»Ž2ä¸å‡åŽÈš„ž®±æ˜¯˜q™ä¸ªå€¹{€?é—憾的是åQŒè¿™ä¸ªè®¡½Ž—çš„¾l“æžœòq¶ä¸æ˜¯æœ€æŽ¥è¿‘0.9çš„double倹{€?表示¾l“果的double值的最çŸè¡¨½Cºå°±æ˜¯ä½ 所看到的打å°å‡ºæ¥çš„那个å¯æ¶çš„æ•°å—ã€?/p>
<h2>½W?2 天问题的解决办法</h2>
<h3>æ–ÒŽ(gu¨©)³•ä¸€</h3>
<pre>
<code class="java">
<span id="wmqeeuq" class="comment">//拙劣的解å†Ïx(ch¨®ng)–¹æ¡?-ä»æ—§æ˜¯ä‹É用二˜q›åˆ¶‹¹®ç‚¹æ•?/span>
System.out.printf(<span id="wmqeeuq" class="string">"%.2f%n"</span>,<span id="wmqeeuq" class="number">2.00</span> - <span id="wmqeeuq" class="number">1.10</span>);</code>
</pre>
<p>˜q™æ¡è¯å¥æ‰“å°çš„是æ£ç¡®çš„结果，但是˜q™åƈä¸è¡¨½Cºå®ƒ?y¨u)®±æ˜¯å¯¹åº•å±‚问题的通用解决æ–ÒŽ(gu¨©)¡ˆã€‚它使用的ä»æ—§æ˜¯äºŒè¿›åˆ¶æÕQç‚ÒŽ(gu¨©)•°çš„double˜qç®—ã€?‹¹®ç‚¹˜q算在一个范围很òq¿çš„值域上æ供了(ji¨£n)很好的近ä¼û|¼Œä½†æ˜¯å®ƒé€šå¸¸ä¸èƒ½äº§ç”Ÿ¾_„¡¡®çš„结果ã€?<strong>二进制æÕQ点对于货å¸è®¡½Ž—是éžå¸¸ä¸é€‚åˆçš?/strong>åQŒå› 为它ä¸å¯èƒ½å°†0.1--或è€?0的其它ä“Q何次负幂--¾_„¡¡®è¡¨ç¤ºä¸ÞZ¸€ä¸ªé•¿åº¦æœ‰é™çš„二进制å°æ•?/p>
<h3>æ–ÒŽ(gu¨©)³•äº?/h3>
<pre>
<code class="java">System.out.println((<span id="wmqeeuq" class="number">200</span> - <span id="wmqeeuq" class="number">110</span>) + <span id="wmqeeuq" class="string">"�</span>);</code>
</pre>
<p>˜q™æ˜¯åœ¨Javaä¸ä¸€¿U简å•çš„解决æ–ÒŽ(gu¨©)³•ã€‚在Javaæ ‡å‡†åº“ä¸åQŒæœ‰ä¸€ä¸ªç±»ä¼¼çš„范例Date¾c»ï¼ŒDate¾cÈš„对于旉™—´çš„内部表½Cºå°±æ˜¯ä¸€ä¸ªä»¥æ¯«ç§’为å•ä½çš„longæ•´æ•°ã€?对于åƒè´§å¸è¿™æ ïL(f¨¥ng)š„æ•°å€û|¼Œå¯ä»¥ç”¨int或longæ¥è¡¨½Cºã€‚å¦‚æžœä½ é‡‡çº³äº?ji¨£n)解å†Ïx(ch¨®ng)–¹æ³•ï¼Œ<strong>è¯ïL(f¨¥ng)¡®ä¿è¯¥æ•´æ•°¾cÕdž‹å¤§åˆ°‘›_¤Ÿè¡¨ç¤ºåœ¨ç¨‹åºä¸ä½ å°†è¦ç”¨åˆ°çš„所有å€?/strong>ã€?/p>
<h3>æ–ÒŽ(gu¨©)³•ä¸?/h3>
<pre>
<code class="java">
<span id="wmqeeuq" class="keyword">import</span> java.math.BigDecimal;
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">class</span> <span id="wmqeeuq" class="title">Change1</span>{
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">void</span> main(String args[]){
System.out.println(<span id="wmqeeuq" class="keyword">new</span> BigDecimal(<span id="wmqeeuq" class="string">"2.00"</span>).subtract(<span id="wmqeeuq" class="keyword">new</span> BigDecimal(<span id="wmqeeuq" class="string">"1.10"</span>)));
}
}
</code>
</pre>
<p>解决该问题的å¦ä¸€¿Uæ–¹å¼æ˜¯ä½¿ç”¨æ‰§è¡Œ¾_„¡¡®ž®æ•°˜qç®—çš„BigDecimalã€?<strong>˜q™é‡Œè¦å‘Šè¯«ä½ 一点：(x¨¬) 一定è¦ç”¨BigDecimal(String)æž„é€ å™¨åQŒè€Œåƒä¸‡ä¸è¦ç”¨BigDecimal(double)ã€?åŽä¸€ä¸ªæž„é€ å™¨ž®†ç”¨å®ƒçš„å‚æ•°çš?¾_„¡¡®"值æ¥åˆ›å¾ä¸€ä¸ªå®žä¾‹ï¼š(x¨¬)new BigDecimal(1.1)ž®†è¿”回一个表½C?.100000000000000055511151231257827021181583404541015625 çš„BigDecimalã€?/strong>
</p>
<p>˜q™ä¸ªç‰ˆæœ¬òq¶ä¸æ˜¯å分地完美åQŒå› 为Javaòq¶æ²¡æœ‰äØ“(f¨´)BigDecimalæä¾›ä»ÖM½•è¯è¨€ä¸Šçš„支æŒã€‚åŽŸå› ï¼š(x¨¬)</p>
<ul>
<li>使用BigDecimal的计½Ž—很有å¯èƒ½æ¯”那些使用原始¾cÕdž‹çš„计½Ž—è¦æ…¢ä¸€äº›ï¼Œå¯ÒŽ(gu¨©)Ÿäº›å¤§é‡ä‹É用å°æ•°è®¡½Ž—çš„½E‹åºæ¥è¯´åQŒè¿™å¯èƒ½ä¼?x¨¬)æˆä¸ºé—®é¢˜ï¼Œè€Œå¯¹å¤§å¤šæ•°ç¨‹åºæ¥è¯ß_(d¨¢)¼Œ˜q™æ˜¾å¾—一点也ä¸é‡è¦ã€?/li>
<li>Javaä¸å…许追Ž—符é‡è²ã€‚ä‹É得代ç ä¸å¤Ÿç›´è§‚ã€?/li>
</ul>
<h2>æ€È»“</h2>
<p>在需è¦ç²¾¼‹®ç”案的地方åQŒè¦é¿å…使用floatå’Œdoubleã€?/p>
<p>对于货å¸è®¡ç®—åQŒè¦ä½¿ç”¨intã€long或BigDecimalã€?/p>
<p>对于è¯è¨€è®¾è®¡è€…æ¥è¯ß_(d¨¢)¼Œåº”该考虑对å°æ•°è¿½Ž—æä¾›è¯a€æ”¯æŒã€‚å¯ä»¥æ”¯æŒä¸‹åˆ—æ–¹å¼ä¸çš„一¿Uã€?/p>
<ul>
<li>æä¾›å¯ÒŽ(gu¨©)“作符é‡è²çš„有é™æ”¯æŒï¼Œ 以ä‹É得追Ž—符å¯ä»¥è¢«å¡‘é€ äØ“(f¨´)能够å¯ÒŽ(gu¨©)•°å€¼å¼•ç”¨ç±»åž‹è“v作用åQ?例如BigDecimalã€?/li>
<li>æ供原始的å°æ•°ç±»åž‹ï¼Œž®±åƒ COBOL ä¸?PL/I æ‰€ä½œçš„ä¸€æ —÷€?/li>
</ul>
<hr id="hr"/>
<h2>今天的问�/h2>
<p>被除数表½Cºçš„是一天里的微¿U’æ•°åQ›è€Œé™¤æ•°è¡¨½Cºçš„是一天里的毫¿U’数。这个程åºä¼š(x¨¬)打å°å‡ÞZ»€ä¹ˆå‘¢åQ?/p>
<pre>
<code class="java">
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">class</span> <span id="wmqeeuq" class="title">LongDivision</span>{
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">void</span> main(String args[]){
<span id="wmqeeuq" class="keyword">final</span> <span id="wmqeeuq" class="keyword">long</span> MICROS_PER_DAY = <span id="wmqeeuq" class="number">24</span> * <span id="wmqeeuq" class="number">60</span> * <span id="wmqeeuq" class="number">60</span> * <span id="wmqeeuq" class="number">1000</span> * <span id="wmqeeuq" class="number">1000</span>;
<span id="wmqeeuq" class="keyword">final</span> <span id="wmqeeuq" class="keyword">long</span> MILLIS_PER_DAY = <span id="wmqeeuq" class="number">24</span> * <span id="wmqeeuq" class="number">60</span> * <span id="wmqeeuq" class="number">60</span> * <span id="wmqeeuq" class="number">1000</span>;
System.out.println(MICROS_PER_DAY/MILLIS_PER_DAY);
}
}
</code>
</pre>
<img src ="http://www.aygfsteel.com/fourlee/aggbug/201016.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.aygfsteel.com/fourlee/" target="_blank">æŽå››é£žåˆ€</a> 2008-05-16 22:50 <a href="http://www.aygfsteel.com/fourlee/archive/2008/05/16/201016.html#Feedback" target="_blank" style="text-decoration:none;">å‘表评论</a></div>]]></description></item><item><title>½W?2 天：(x¨¬) è§£ç” -- 判æ–是å¦ä¸ºå¥‡æ•ŽÍ¼Œ 问题 -- æ‰ùN›¶é’?/title><link>http://www.aygfsteel.com/fourlee/archive/2008/05/16/200996.html</link><dc:creator>æŽå››é£žåˆ€</dc:creator><author>æŽå››é£žåˆ€</author><pubDate>Fri, 16 May 2008 13:38:00 GMT</pubDate><guid>http://www.aygfsteel.com/fourlee/archive/2008/05/16/200996.html</guid><wfw:comment>http://www.aygfsteel.com/fourlee/comments/200996.html</wfw:comment><comments>http://www.aygfsteel.com/fourlee/archive/2008/05/16/200996.html#Feedback</comments><slash:comments>2</slash:comments><wfw:commentRss>http://www.aygfsteel.com/fourlee/comments/commentRss/200996.html</wfw:commentRss><trackback:ping>http://www.aygfsteel.com/fourlee/services/trackbacks/200996.html</trackback:ping><description><![CDATA[
<h2>½W?1 天的问题</h2>
<p>下é¢çš„方法æ„囄¡¡®å®šå®ƒé‚£å”¯ä¸€çš„å‚数是å¦æ˜¯ä¸€ä¸ªå¥‡æ•°ã€‚这个方法能够棼‹®è¿è½¬å—åQ?/p>
<pre>
<code class="java"> <span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">boolean</span> odd(<span id="wmqeeuq" class="keyword">int</span> number) {
<span id="wmqeeuq" class="keyword">return</span> number % <span id="wmqeeuq" class="number">2</span> == <span id="wmqeeuq" class="number">1</span>;
}
</code>
</pre>
<h2>½W?1 天问题的解ç”</h2>
<p>æœ?/4的情况下åQŒç”案是错误的。比如：(x¨¬)odd(-3) 表达å¼å¾—到的¾l“æžœž®±æ˜¯ fasle。对于所有的负奇敎ͼŒä¸Šé¢çš„方法都ä¼?x¨¬)得到错误的¾l“æžœã€?/p>
<h3>åŽŸå› </h3>
<p>é—®é¢˜çš„åŽŸå› åœ¨äºŽæ±‚ä½™æ“作符(%)åQŒåœ¨Javaä¸è¯¥æ“作½W¦è¢«å®šä¹‰ä¸?/p>
<blockquote>
<p>对于所有的 int æ•°å€?a 和所有的éžé›¶ int æ•°å€?båQŒéƒ½æ»¡èƒö下é¢çš„æ’½{‰å¼
<br/>
(a / b) * b + (a % b) == a</p>
</blockquote>
<p>æ¢å¥è¯è¯´åQ?a % b) = a - (a / b) * b</p>
<p>由数å¦æŽ¨ç†è¿½Ž—å¯çŸ¥ï¼Œa % b 的符åähœ‰æ“作数a军_®šåQˆè¦ä¹ˆäØ“(f¨´)0åQŒè¦ä¹ˆå’Œa一è‡ß_(d¨¢)¼‰(j¨ª)。也ž®±æ˜¯è¯ß_(d¨¢)¼Œ -5 % 3 => -2åQ?-5 % -3 => -2ã€?/p>
<p>å› æ¤åQŒå¯¹äºŽæ‰€æœ‰çš„负奇数nåQ?n % 2 => -1。问题ä(sh¨´)¸çš„方法自然有问题啦ã€?/p>
<h3>解决办法</h3>
<p>è¦åˆ¤æ–一个整数是å¦äØ“(f¨´)奇数的解军_Šžæ³•æœ‰ä¸¤ç§ã€?/p>
<pre>
<code class="java"> <span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">boolean</span> odd(<span id="wmqeeuq" class="keyword">int</span> number) {
<span id="wmqeeuq" class="keyword">return</span> number % <span id="wmqeeuq" class="number">2</span> != <span id="wmqeeuq" class="number">0</span>;
}
</code>
</pre>
<pre>
<code class="java"> <span id="wmqeeuq" class="javadoc">/**
* ˜q™ç§æ–ÒŽ(gu¨©)³•çš„性能更好ã€? */</span>
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">boolean</span> odd(<span id="wmqeeuq" class="keyword">int</span> number) {
<span id="wmqeeuq" class="keyword">return</span> (number & <span id="wmqeeuq" class="number">1</span>) != <span id="wmqeeuq" class="number">0</span>;
}
</code>
</pre>
<h2>æ€È»“</h2>
<p>
<strong>æ— è®ºä½ ä½•æ—¶ä‹É用到äº?ji¨£n)å–ä½™æ“作符åQŒéƒ½è¦è€ƒè™‘到æ“作数和结果的½W¦å·ã€?/strong>
</p>
<p>该æ“作符的行为在其æ“作数éžè´Ÿæ—¶æ˜¯ä¸€ç›®äº†(ji¨£n)然的åQŒä½†æ˜¯å½“一个或两个æ“作数都是负数时åQŒå®ƒçš„行为就ä¸é‚£ä¹ˆæ˜¾è€Œæ˜“è§äº†(ji¨£n)ã€?/p>
<hr id="hr"/>
<h2>今天的问�/h2>
<p>误‚€(g¨¨)ƒè™‘下题q™æ®µè¯æ‰€æ述的问题：(x¨¬)</p>
<p>ž®æ˜Žåœ¨è¶…å¸?j¨¬ng)è´ä¹îCº†(ji¨£n)一个äh(hu¨¢n)å€û|òE1.10的东西，但是他钱包ä¸åªæœ‰ä¸¤å…ƒä¸€å¼ çš„é’žç¥¨ã€‚å¦‚æžœä»–ç”¨ä¸€å¼ ä¸¤å…ƒçš„é’žç¥¨æ”¯ä»˜åQŒé‚£ä¹ˆåº”该找¾l™ä»–多少雉™’±å‘¢ï¼Ÿ</p>
<p>下é¢æ˜¯ä¸€ä¸ªè¯•å›¾è§£å†³ä¸Š˜q°é—®é¢˜çš„½E‹åºåQŒå®ƒä¼?x¨¬)打å°å‡ºä»€ä¹ˆå‘¢åQ?/p>
<pre>
<code class="java">
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">class</span> <span id="wmqeeuq" class="title">Change</span>{
<span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">void</span> main(String args[]){
System.out.println(<span id="wmqeeuq" class="number">2.00</span> - <span id="wmqeeuq" class="number">1.10</span>);
}
}
</code>
</pre>
<img src ="http://www.aygfsteel.com/fourlee/aggbug/200996.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.aygfsteel.com/fourlee/" target="_blank">æŽå››é£žåˆ€</a> 2008-05-16 21:38 <a href="http://www.aygfsteel.com/fourlee/archive/2008/05/16/200996.html#Feedback" target="_blank" style="text-decoration:none;">å‘表评论</a></div>]]></description></item><item><title>½W?1 天：(x¨¬) 判æ–是å¦ä¸ºå¥‡æ•?/title><link>http://www.aygfsteel.com/fourlee/archive/2008/05/16/200989.html</link><dc:creator>æŽå››é£žåˆ€</dc:creator><author>æŽå››é£žåˆ€</author><pubDate>Fri, 16 May 2008 12:53:00 GMT</pubDate><guid>http://www.aygfsteel.com/fourlee/archive/2008/05/16/200989.html</guid><wfw:comment>http://www.aygfsteel.com/fourlee/comments/200989.html</wfw:comment><comments>http://www.aygfsteel.com/fourlee/archive/2008/05/16/200989.html#Feedback</comments><slash:comments>3</slash:comments><wfw:commentRss>http://www.aygfsteel.com/fourlee/comments/commentRss/200989.html</wfw:commentRss><trackback:ping>http://www.aygfsteel.com/fourlee/services/trackbacks/200989.html</trackback:ping><description><![CDATA[
<p>
<span style="FONT-SIZE: 12pt; FONT-FAMILY: å®?hu¨¤)ä½? mso-bidi-font-family: å®?hu¨¤)ä½? mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">下é¢çš„方法æ„囄¡¡®å®šå®ƒé‚£å”¯ä¸€çš„å‚数是å¦æ˜¯ä¸€ä¸ªå¥‡æ•°ã€‚这个方法能够棼‹®è¿è½¬å—åQ?/span>
</p>
<pre>
<code class="java"> <span id="wmqeeuq" class="keyword">public</span> <span id="wmqeeuq" class="keyword">static</span> <span id="wmqeeuq" class="keyword">boolean</span> odd(<span id="wmqeeuq" class="keyword">int</span> number) {
<span id="wmqeeuq" class="keyword">return</span> number % <span id="wmqeeuq" class="number">2</span> == <span id="wmqeeuq" class="number">1</span>;
}
</code>
</pre>
<img src ="http://www.aygfsteel.com/fourlee/aggbug/200989.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.aygfsteel.com/fourlee/" target="_blank">æŽå››é£žåˆ€</a> 2008-05-16 20:53 <a href="http://www.aygfsteel.com/fourlee/archive/2008/05/16/200989.html#Feedback" target="_blank" style="text-decoration:none;">å‘表评论</a></div>]]></description></item><item><title>HTTP(一)http://www.aygfsteel.com/fourlee/archive/2008/02/04/179305.htmlæŽå››é£žåˆ€æŽå››é£žåˆ€Mon, 04 Feb 2008 10:57:00 GMThttp://www.aygfsteel.com/fourlee/archive/2008/02/04/179305.htmlhttp://www.aygfsteel.com/fourlee/comments/179305.htmlhttp://www.aygfsteel.com/fourlee/archive/2008/02/04/179305.html#Feedback0http://www.aygfsteel.com/fourlee/comments/commentRss/179305.htmlhttp://www.aygfsteel.com/fourlee/services/trackbacks/179305.html
HTTP
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Date: Sun, 03 Feb 2008 08:08:44 GMT
Server: BWS/1.0
Content-Length: 3022
Content-Type: text/html
Cache-Control: private
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Set-Cookie: BAIDUID=2BB1B837C8EC6794A132C5D8DDD76721:FG=1; expires=Sun, 03-Feb-38 08:08:44 GMT; path=/; domain=.baidu.com
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@charset "utf-8";
/**
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*/
/* 控制å°è¾¹æ¡†å±‚ */
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background: #000000 url(Command_heading.jpg) no-repeat;
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margin: 0px;
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padding-right: 0px;
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}
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background-color: #000000;
font-family: "Courier New", Courier, "å®?hu¨¤)ä½?, monospace;
font-size: 12px;
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