�??xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/"><channel><title>&#x4E9A;&#x6D32;&#x56FD;&#x4EA7;&#x6B27;&#x7F8E;&#x4E00;&#x533A;&#x2C;&#x7CBE;&#x54C1;&#x4E45;&#x4E45;&#x89C6;&#x9891;&#x2C;&#x4E2D;&#x6587;&#x5B57;&#x5E55;&#x6B27;&#x7F8E;&#x65E5;&#x97E9;&#x4E00;&#x533A;&#x4E8C;&#x533A;&#x4E09;&#x533A;</title><link>http://www.aygfsteel.com/jorwen/category/7238.html</link><description /><language>zh-cn</language><lastBuildDate>Wed, 28 Feb 2007 11:49:35 GMT</lastBuildDate><pubDate>Wed, 28 Feb 2007 11:49:35 GMT</pubDate><ttl>60</ttl><item><title>一���不错的讲解Java异常的文�?/title><link>http://www.aygfsteel.com/jorwen/articles/29425.html</link><dc:creator>方佳�?/dc:creator><author>方佳�?/author><pubDate>Wed, 01 Feb 2006 04:36:00 GMT</pubDate><guid>http://www.aygfsteel.com/jorwen/articles/29425.html</guid><wfw:comment>http://www.aygfsteel.com/jorwen/comments/29425.html</wfw:comment><comments>http://www.aygfsteel.com/jorwen/articles/29425.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://www.aygfsteel.com/jorwen/comments/commentRss/29425.html</wfw:commentRss><trackback:ping>http://www.aygfsteel.com/jorwen/services/trackbacks/29425.html</trackback:ping><description><![CDATA[<SPAN id=ArticleContent1_ArticleContent1_lblContent>
<P><FONT size=2>六种异常处理的陋�?/FONT></P>
<P><FONT size=2>你觉得自己是一个Java专家吗？是否肯定自己已经全面掌握了Java的异常处理机�Ӟ��在下面这�D�代码中�Q�你能够�q�速找出异常处理的六个问题吗？<BR><BR></P>
<DIV style="BORDER-RIGHT: #cccccc 1px solid; PADDING-RIGHT: 5px; BORDER-TOP: #cccccc 1px solid; PADDING-LEFT: 4px; FONT-SIZE: 13px; PADDING-BOTTOM: 4px; BORDER-LEFT: #cccccc 1px solid; WIDTH: 98%; WORD-BREAK: break-all; PADDING-TOP: 4px; BORDER-BOTTOM: #cccccc 1px solid; BACKGROUND-COLOR: #eeeeee"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top><SPAN style="COLOR: #000000">1</SPAN><SPAN style="COLOR: #000000">&nbsp;OutputStreamWriter&nbsp;out&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;<IMG src="http://www.aygfsteel.com/images/dot.gif">&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top></SPAN><SPAN style="COLOR: #000000">2</SPAN><SPAN style="COLOR: #000000">&nbsp;java.sql.Connection&nbsp;conn&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;<IMG src="http://www.aygfsteel.com/images/dot.gif">&nbsp;<BR><IMG id=Codehighlighter1_72_368_Open_Image onclick="this.style.display='none'; Codehighlighter1_72_368_Open_Text.style.display='none'; Codehighlighter1_72_368_Closed_Image.style.display='inline'; Codehighlighter1_72_368_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockStart.gif" align=top><IMG id=Codehighlighter1_72_368_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_72_368_Closed_Text.style.display='none'; Codehighlighter1_72_368_Open_Image.style.display='inline'; Codehighlighter1_72_368_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">3</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">try</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN id=Codehighlighter1_72_368_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_72_368_Open_Text><SPAN style="COLOR: #000000">{&nbsp;</SPAN><SPAN style="COLOR: #008000">//</SPAN><SPAN style="COLOR: #008000">&nbsp;�?nbsp;</SPAN><SPAN style="COLOR: #008000"><BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">4</SPAN><SPAN style="COLOR: #000000">&nbsp;　Statement&nbsp;stat&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;conn.createStatement();&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">5</SPAN><SPAN style="COLOR: #000000">&nbsp;　ResultSet&nbsp;rs&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;stat.executeQuery(&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">6</SPAN><SPAN style="COLOR: #000000">&nbsp;　　</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">select&nbsp;uid,&nbsp;name&nbsp;from&nbsp;user</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">);&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">7</SPAN><SPAN style="COLOR: #000000">&nbsp;　</SPAN><SPAN style="COLOR: #0000ff">while</SPAN><SPAN style="COLOR: #000000">&nbsp;(rs.next())&nbsp;<BR><IMG id=Codehighlighter1_224_320_Open_Image onclick="this.style.display='none'; Codehighlighter1_224_320_Open_Text.style.display='none'; Codehighlighter1_224_320_Closed_Image.style.display='inline'; Codehighlighter1_224_320_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_224_320_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_224_320_Closed_Text.style.display='none'; Codehighlighter1_224_320_Open_Image.style.display='inline'; Codehighlighter1_224_320_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">8</SPAN><SPAN style="COLOR: #000000">&nbsp;　</SPAN><SPAN id=Codehighlighter1_224_320_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_224_320_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">9</SPAN><SPAN style="COLOR: #000000">&nbsp;　　out.println(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">ID�Q?/SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;rs.getString(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">uid</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">)&nbsp;</SPAN><SPAN style="COLOR: #008000">//</SPAN><SPAN style="COLOR: #008000">&nbsp;�?nbsp;</SPAN><SPAN style="COLOR: #008000"><BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">10</SPAN><SPAN style="COLOR: #000000">&nbsp;　　　</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">�Q�姓名：(x��)</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;rs.getString(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">name</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">));&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top></SPAN><SPAN style="COLOR: #000000">11</SPAN><SPAN style="COLOR: #000000">&nbsp;　}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">12</SPAN><SPAN style="COLOR: #000000">&nbsp;　conn.close();&nbsp;</SPAN><SPAN style="COLOR: #008000">//</SPAN><SPAN style="COLOR: #008000">&nbsp;�?nbsp;</SPAN><SPAN style="COLOR: #008000"><BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">13</SPAN><SPAN style="COLOR: #000000">&nbsp;　out.close();&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockEnd.gif" align=top></SPAN><SPAN style="COLOR: #000000">14</SPAN><SPAN style="COLOR: #000000">&nbsp;}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top></SPAN><SPAN style="COLOR: #000000">15</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">catch</SPAN><SPAN style="COLOR: #000000">(Exception&nbsp;ex)&nbsp;</SPAN><SPAN style="COLOR: #008000">//</SPAN><SPAN style="COLOR: #008000">&nbsp;�?nbsp;</SPAN><SPAN style="COLOR: #008000"><BR><IMG id=Codehighlighter1_403_442_Open_Image onclick="this.style.display='none'; Codehighlighter1_403_442_Open_Text.style.display='none'; Codehighlighter1_403_442_Closed_Image.style.display='inline'; Codehighlighter1_403_442_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockStart.gif" align=top><IMG id=Codehighlighter1_403_442_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_403_442_Closed_Text.style.display='none'; Codehighlighter1_403_442_Open_Image.style.display='inline'; Codehighlighter1_403_442_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">16</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN id=Codehighlighter1_403_442_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_403_442_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top></SPAN><SPAN style="COLOR: #000000">17</SPAN><SPAN style="COLOR: #000000">&nbsp;　ex.printStackTrace();&nbsp;</SPAN><SPAN style="COLOR: #008000">//</SPAN><SPAN style="COLOR: #008000">��_(d��)���?nbsp;</SPAN><SPAN style="COLOR: #008000"><BR><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockEnd.gif" align=top></SPAN><SPAN style="COLOR: #000000">18</SPAN><SPAN style="COLOR: #000000">&nbsp;}</SPAN></SPAN></DIV></FONT></SPAN><BR><FONT size=2>作�ؓ(f��)一个Java�E�序员，你至���应该能够找��Z��个问题。但是，如果你不能找出全部六个问题，��L(f��ng)���l�阅��L��文�?<BR><BR>　　本文讨论的不是Java异常处理的一般性原则，因�ؓ(f��)�q�些原则已经被大多数人熟知。我们要做的是分析各�U�可�U�Cؓ(f��)“反例”（anti-pattern�Q�的�q�背优秀�~�码规范的常见坏�?f��n)惯�Q�帮助读者熟�(zh��n)�这些典型的反面例子�Q�从而能够在实际工作中敏锐地察觉和避免这些问题�?<BR><BR>　　<B>反例之一�Q�丢弃异�?</B><BR><BR>　　代码�Q?5�?18行�?<BR><BR>　　�q�段代码捕获了异常却不作��M��处理�Q�可以算得上Java�~�程中的杀手。从问题出现的频�J�程度和���害�E�度来看�Q�它也许可以和C/C++�E�序的一个恶名远播的问题相提�q�论??不检查缓冲区是否已满。如果你看到了这�U�丢弃（而不是抛出）异常的情况，可以癑ֈ�之九(ji��)十九(ji��)地肯定代码存在问题（在极���数情况下，�q�段代码有存在的理由�Q�但最好加上完整的注释�Q�以免引起别�����解）�?<BR><BR>　　�q�段代码的错误在于，异常�Q�几乎）��L��意味着某些事情不对劲了�Q�或者说臛_��发生了某些不��d��的事情，我们不应该对�E�序发出的求救信号保持沉默和无动于衷。调用一下printStackTrace���不上“处理异常”。不错，调用printStackTrace对调试程序有帮助�Q�但�E�序调试阶段�l�束之后�Q�printStackTrace��׃��应再在异常处理模块中担负主要责�Q了�?<BR><BR>　　丢弃异常的情形非常普遍。打开JDK的ThreadDeath�cȝ��文档�Q�可以看��C��面这�D�说明：(x��)“特别地�Q�虽然出现ThreadDeath是一�U�‘正常的情�Ş’，但ThreadDeath�c�L��Error而不是Exception的子�c�，因�ؓ(f��)许多应用�?x��)捕��h��有的Exception然后丢弃它不再理睬。”这�D�话的意思是�Q�虽然ThreadDeath代表的是一�U�普通的问题�Q�但鉴于许多应用�?x��)试图捕��h��有异常然后不予以适当的处理，所以JDK把ThreadDeath定义成了Error的子�c�，因�ؓ(f��)Error�c�M��表的是一般的应用不应该去捕获的严重问题。可见，丢弃异常�q�一坏习(f��n)惯是如此常见�Q�它甚至已经影响��C��Java本��n的设计�?<BR><BR>　　那么�Q�应该怎样�Ҏ(gu��)��呢？主要有四个选择�Q?<BR><BR>　　1、处理异常。针对该异常采取一些行动，例如修正问题、提醒某个�h或进行其他一些处理，要根据具体的情�Ş���定应该采取的动作。再�ơ说明，调用printStackTrace���不上已�l�“处理好了异常”�?<BR><BR>　　2、重新抛出异常。处理异常的代码在分析异�怹�后，认�ؓ(f��)自己不能处理它，重新抛出异常也不�׃ؓ(f��)一�U�选择�?<BR><BR>　　3、把该异常�{换成另一�U�异常。大多数情况下，�q�是指把一个低�U�的异常转换成应用��的异常（其含义更�Ҏ(gu��)��被用户了解的异常�Q��?<BR><BR>　　4、不要捕获异常�?<BR><BR>　　�l�论一�Q�既然捕获了异常�Q�就要对它进行适当的处理。不要捕获异�怹�后又把它丢弃�Q�不予理睬�?<BR><BR>　　<B>反例之二�Q�不指定具体的异�?</B><BR><BR>　　代码�Q?5行�?<BR><BR>　　许多时候�h们会(x��)被这样一�U�“美妙的”想法吸引：(x��)用一个catch语句捕获所有的异常。最常见的情形就是��用catch(Exception ex)语句。但实际上，在绝大多数情况下�Q�这�U�做法不值得提倡。�ؓ(f��)什么呢�Q?<BR><BR>　　要理解其原因�Q�我们必���d����一下catch语句的用途。catch语句表示我们预期�?x��)出现某�U�异常，而且希望能够处理该异常。异常类的作用就是告诉Java�~�译器我们想要处理的是哪一�U�异常。由于绝大多数异帔R��直接或间接从java.lang.Exception�z�����Q�catch(Exception ex)���q��当于说我们想要处理几乎所有的异常�?<BR><BR>　　再来看看前面的代码例子。我们真正想要捕��L(f��ng)��异常是什么呢�Q�最明显的一个是SQLException�Q�这是JDBC操作中常见的异常。另一个可能的异常是IOException�Q�因为它要操作OutputStreamWriter。显�Ӟ��在同一个catch块中处理�q�两�U�截然不同的异常是不合适的。如果用两个catch块分别捕获SQLException和IOException���p��好多了。这���是��_(d��)��catch语句应当���量指定具体的异常类型，而不应该指定�늛�范围太广的Exception�c�R�?<BR><BR>　　另一斚w���Q�除了这两个特定的异常，�q�有其他许多异常也可能出现。例如，如果�׃��某种原因�Q�executeQuery�q�回了null�Q�该怎么办？�{�案是让它们�l�箋抛出�Q�即不必捕获也不必处理。实际上�Q�我们不能也不应该去捕获可能出现的所有异常，�E�序的其他地方还有捕获异常的��Z��(x��)??直至最后由JVM处理�?<BR><BR>　　�l�论二：(x��)在catch语句中尽可能指定具体的异常类型，必要时��用多个catch。不要试囑֤�理所有可能出现的异常�?<BR><BR>　　<B>反例之三�Q�占用资源不释放 </B><BR><BR>　　代码�Q?�?14行�?<BR><BR>　　异常改变了程序正常的执行���程。这个道理虽然简单，却常常被��Z��忽视。如果程序用��C��文�g、Socket、JDBC�q�接之类的资源，即��遇到了异常，也要正确释放占用的资源。�ؓ(f��)此，Java提供了一个简化这�c�L��作的关键词finally�?<BR><BR>　　finally是样好东西：(x��)不管是否出现了异常，Finally保证在try/catch/finally块结束之前，执行清理��d��的代码��L��有机�?x��)执行。遗憄���是有些�h却不�?f��n)惯使用finally�?<BR><BR>　　当然�Q�编写finally块应当多加小心，特别是要注意在finally块之内抛出的异常??�q�是执行清理��d��的最后机�?x��)，���量不要再有难以处理的错误�?<BR><BR>　　�l�论三：(x��)保证所有资源都被正���释放。充分运用finally关键词�?/FONT>
<P><FONT size=2><STRONG>反例之四�Q�不说明异常的详�l�信�?<BR><BR></STRONG>　　代码�Q?�?18行�?<BR><BR>　　仔细观察�q�段代码�Q�如果��@环内部出��C��异常�Q�会(x��)发生什么事情？我们可以得到���_��的信息判断��@环内部出错的原因吗？不能。我们只能知道当前正在处理的�c�d��生了某种错误�Q�但却不能获得�Q何信息判断导致当前错误的原因�?<BR><BR>　　printStackTrace的堆栈跟�t�功能显�C�出�E�序�q�行到当前类的执行流�E�，但只提供了一些最基本的信息，未能说明实际��D��错误的原因，同时也不易解诅R�?<BR><BR>　　因此�Q�在出现异常�Ӟ��最好能够提供一些文字信息，例如当前正在执行的类、方法和其他状态信息，包括以一�U�更适合阅读的方式整理和�l�织printStackTrace提供的信息�?<BR><BR>　　�l�论四：(x��)在异常处理模块中提供适量的错误原因信息，�l�织错误信息使其易于理解和阅诅R�?<BR><BR>　　<B>反例之五�Q�过于庞大的try�?</B><BR><BR>　　代码�Q?�?14行�?<BR><BR>　　�l�常可以看到有�h把大量的代码攑օ�单个try块，实际上这不是好习(f��n)惯。这�U�现象之所以常见，原因���在于有些�h囄���事，不愿花时间分析一大块代码中哪几行代码�?x��)抛出异常、异常的具体�c�d��是什么。把大量的语句装入单个巨大的try块就象是出门旅游时把所有日常用品塞入一个大���子�Q�虽然东西是带上了，但要扑և�来可不容易�?<BR><BR>　　一些新手常常把大量的代码放入单个try块，然后再在catch语句中声明Exception�Q�而不是分���d��个可能出现异常的�D�落�q�分别捕获其异常。这�U�做法�ؓ(f��)分析�E�序抛出异常的原因带来了困难�Q�因��Z��大段代码中有太多的地方可能抛出Exception�?<BR><BR>　　�l�论五：(x��)���量减小try块的体积�?<BR><BR>　　<B>反例之六�Q�输出数据不完整</B> <BR><BR>　　代码�Q?�?11行�?<BR><BR>　　不完整的数据是Java�E�序的隐形杀手。仔�l�观察这�D�代码，考虑一下如果��@环的中间抛出了异常，�?x��)发生什么事情。��@环的执行当然是要被打断的�Q�其�ơ，catch块会(x��)执行??���p��些，再也没有其他动作了。已�l�输出的数据怎么办？使用�q�些数据的�h或设备将收到一份不完整的（因而也是错误的�Q�数据，却得不到��M��有关�q�䆾数据是否完整的提�C�。对于有些系�l�来��_(d��)��数据不完整可能比�pȝ��停止�q�行带来更大的损失�?<BR><BR>　　较�ؓ(f��)理想的处�|�办法是向输�����备写一些信息，声明数据的不完整性；另一�U�可能有效的办法是，先缓冲要输出的数据，准备好全部数据之后再一�ơ性输出�?<BR><BR>　　�l�论六：(x��)全面考虑可能出现的异�总��?qi��ng)这些异常对执行���程的媄响�?<BR><BR>　　<B>改写后的代码</B> <BR><BR>　　�Ҏ(gu��)��上面的讨论，下面�l�出改写后的代码。也许有��Z��(x��)说它�E�微有点?嗦，但是它有了比较完备的异常处理机制�?<BR></P>
<DIV style="BORDER-RIGHT: #cccccc 1px solid; PADDING-RIGHT: 5px; BORDER-TOP: #cccccc 1px solid; PADDING-LEFT: 4px; FONT-SIZE: 13px; PADDING-BOTTOM: 4px; BORDER-LEFT: #cccccc 1px solid; WIDTH: 98%; WORD-BREAK: break-all; PADDING-TOP: 4px; BORDER-BOTTOM: #cccccc 1px solid; BACKGROUND-COLOR: #eeeeee"><SPAN style="COLOR: #008080">&nbsp;1</SPAN><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top><SPAN style="COLOR: #000000">OutputStreamWriter&nbsp;out&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;<IMG src="http://www.aygfsteel.com/images/dot.gif">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;2</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top>java.sql.Connection&nbsp;conn&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;<IMG src="http://www.aygfsteel.com/images/dot.gif">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;3</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_66_288_Open_Image onclick="this.style.display='none'; Codehighlighter1_66_288_Open_Text.style.display='none'; Codehighlighter1_66_288_Closed_Image.style.display='inline'; Codehighlighter1_66_288_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockStart.gif" align=top><IMG id=Codehighlighter1_66_288_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_66_288_Closed_Text.style.display='none'; Codehighlighter1_66_288_Open_Image.style.display='inline'; Codehighlighter1_66_288_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedBlock.gif" align=top></SPAN><SPAN style="COLOR: #0000ff">try</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN id=Codehighlighter1_66_288_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_66_288_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;4</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　Statement&nbsp;stat&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;conn.createStatement();&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;5</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　ResultSet&nbsp;rs&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;stat.executeQuery(&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;6</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　　</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">select&nbsp;uid,&nbsp;name&nbsp;from&nbsp;user</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">);&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;7</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　</SPAN><SPAN style="COLOR: #0000ff">while</SPAN><SPAN style="COLOR: #000000">&nbsp;(rs.next())&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;8</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_203_285_Open_Image onclick="this.style.display='none'; Codehighlighter1_203_285_Open_Text.style.display='none'; Codehighlighter1_203_285_Closed_Image.style.display='inline'; Codehighlighter1_203_285_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_203_285_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_203_285_Closed_Text.style.display='none'; Codehighlighter1_203_285_Open_Image.style.display='inline'; Codehighlighter1_203_285_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top>　</SPAN><SPAN id=Codehighlighter1_203_285_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_203_285_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;9</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　　out.println(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">ID�Q?/SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;rs.getString(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">uid</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">)&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">�Q�姓�?&nbsp;</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;rs.getString(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">name</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">));&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">10</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top>　}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">11</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockEnd.gif" align=top>}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">12</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top></SPAN><SPAN style="COLOR: #0000ff">catch</SPAN><SPAN style="COLOR: #000000">(SQLException&nbsp;sqlex)&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">13</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_318_405_Open_Image onclick="this.style.display='none'; Codehighlighter1_318_405_Open_Text.style.display='none'; Codehighlighter1_318_405_Closed_Image.style.display='inline'; Codehighlighter1_318_405_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockStart.gif" align=top><IMG id=Codehighlighter1_318_405_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_318_405_Closed_Text.style.display='none'; Codehighlighter1_318_405_Open_Image.style.display='inline'; Codehighlighter1_318_405_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedBlock.gif" align=top></SPAN><SPAN id=Codehighlighter1_318_405_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_318_405_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">14</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　out.println(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">警告�Q�数据不完整</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">);&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">15</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　</SPAN><SPAN style="COLOR: #0000ff">throw</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">new</SPAN><SPAN style="COLOR: #000000">&nbsp;ApplicationException(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">��d��数据时出现SQL错误</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">,&nbsp;sqlex);&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">16</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockEnd.gif" align=top>}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">17</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top></SPAN><SPAN style="COLOR: #0000ff">catch</SPAN><SPAN style="COLOR: #000000">(IOException&nbsp;ioex)&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">18</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_433_491_Open_Image onclick="this.style.display='none'; Codehighlighter1_433_491_Open_Text.style.display='none'; Codehighlighter1_433_491_Closed_Image.style.display='inline'; Codehighlighter1_433_491_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockStart.gif" align=top><IMG id=Codehighlighter1_433_491_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_433_491_Closed_Text.style.display='none'; Codehighlighter1_433_491_Open_Image.style.display='inline'; Codehighlighter1_433_491_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedBlock.gif" align=top></SPAN><SPAN id=Codehighlighter1_433_491_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_433_491_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">19</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　</SPAN><SPAN style="COLOR: #0000ff">throw</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">new</SPAN><SPAN style="COLOR: #000000">&nbsp;ApplicationException(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">写入数据时出现IO错误</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">,&nbsp;ioex);&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">20</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockEnd.gif" align=top>}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">21</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top></SPAN><SPAN style="COLOR: #0000ff">finally</SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">22</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_503_877_Open_Image onclick="this.style.display='none'; Codehighlighter1_503_877_Open_Text.style.display='none'; Codehighlighter1_503_877_Closed_Image.style.display='inline'; Codehighlighter1_503_877_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockStart.gif" align=top><IMG id=Codehighlighter1_503_877_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_503_877_Closed_Text.style.display='none'; Codehighlighter1_503_877_Open_Image.style.display='inline'; Codehighlighter1_503_877_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedBlock.gif" align=top></SPAN><SPAN id=Codehighlighter1_503_877_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_503_877_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">23</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_525_692_Open_Image onclick="this.style.display='none'; Codehighlighter1_525_692_Open_Text.style.display='none'; Codehighlighter1_525_692_Closed_Image.style.display='inline'; Codehighlighter1_525_692_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_525_692_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_525_692_Closed_Text.style.display='none'; Codehighlighter1_525_692_Open_Image.style.display='inline'; Codehighlighter1_525_692_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top>　</SPAN><SPAN style="COLOR: #0000ff">if</SPAN><SPAN style="COLOR: #000000">&nbsp;(conn&nbsp;</SPAN><SPAN style="COLOR: #000000">!=</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">null</SPAN><SPAN style="COLOR: #000000">)&nbsp;</SPAN><SPAN id=Codehighlighter1_525_692_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_525_692_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">24</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_534_557_Open_Image onclick="this.style.display='none'; Codehighlighter1_534_557_Open_Text.style.display='none'; Codehighlighter1_534_557_Closed_Image.style.display='inline'; Codehighlighter1_534_557_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_534_557_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_534_557_Closed_Text.style.display='none'; Codehighlighter1_534_557_Open_Image.style.display='inline'; Codehighlighter1_534_557_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top>　　</SPAN><SPAN style="COLOR: #0000ff">try</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN id=Codehighlighter1_534_557_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_534_557_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">25</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　　　conn.close();&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">26</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top>　　}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">27</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　　</SPAN><SPAN style="COLOR: #0000ff">catch</SPAN><SPAN style="COLOR: #000000">(SQLException&nbsp;sqlex2)&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">28</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_592_688_Open_Image onclick="this.style.display='none'; Codehighlighter1_592_688_Open_Text.style.display='none'; Codehighlighter1_592_688_Closed_Image.style.display='inline'; Codehighlighter1_592_688_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_592_688_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_592_688_Closed_Text.style.display='none'; Codehighlighter1_592_688_Open_Image.style.display='inline'; Codehighlighter1_592_688_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top>　　</SPAN><SPAN id=Codehighlighter1_592_688_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_592_688_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">29</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　　　System.err(</SPAN><SPAN style="COLOR: #0000ff">this</SPAN><SPAN style="COLOR: #000000">.getClass().getName()&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">.mymethod&nbsp;-&nbsp;不能关闭数据库连�?&nbsp;</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;sqlex2.toString());&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">30</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top>　　}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">31</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top>　}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">32</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top><BR></SPAN><SPAN style="COLOR: #008080">33</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_714_874_Open_Image onclick="this.style.display='none'; Codehighlighter1_714_874_Open_Text.style.display='none'; Codehighlighter1_714_874_Closed_Image.style.display='inline'; Codehighlighter1_714_874_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_714_874_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_714_874_Closed_Text.style.display='none'; Codehighlighter1_714_874_Open_Image.style.display='inline'; Codehighlighter1_714_874_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top>　</SPAN><SPAN style="COLOR: #0000ff">if</SPAN><SPAN style="COLOR: #000000">&nbsp;(out&nbsp;</SPAN><SPAN style="COLOR: #000000">!=</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">null</SPAN><SPAN style="COLOR: #000000">)&nbsp;</SPAN><SPAN id=Codehighlighter1_714_874_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_714_874_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">34</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_723_745_Open_Image onclick="this.style.display='none'; Codehighlighter1_723_745_Open_Text.style.display='none'; Codehighlighter1_723_745_Closed_Image.style.display='inline'; Codehighlighter1_723_745_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_723_745_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_723_745_Closed_Text.style.display='none'; Codehighlighter1_723_745_Open_Image.style.display='inline'; Codehighlighter1_723_745_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top>　　</SPAN><SPAN style="COLOR: #0000ff">try</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN id=Codehighlighter1_723_745_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_723_745_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">35</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　　　out.close();&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">36</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top>　　}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">37</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　　</SPAN><SPAN style="COLOR: #0000ff">catch</SPAN><SPAN style="COLOR: #000000">(IOException&nbsp;ioex2)&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">38</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_778_870_Open_Image onclick="this.style.display='none'; Codehighlighter1_778_870_Open_Text.style.display='none'; Codehighlighter1_778_870_Closed_Image.style.display='inline'; Codehighlighter1_778_870_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_778_870_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_778_870_Closed_Text.style.display='none'; Codehighlighter1_778_870_Open_Image.style.display='inline'; Codehighlighter1_778_870_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top>　　</SPAN><SPAN id=Codehighlighter1_778_870_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_778_870_Open_Text><SPAN style="COLOR: #000000">{&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">39</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>　　　System.err(</SPAN><SPAN style="COLOR: #0000ff">this</SPAN><SPAN style="COLOR: #000000">.getClass().getName()&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">.mymethod&nbsp;-&nbsp;不能关闭输出文�g</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">&nbsp;ioex2.toString());&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">40</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top>　　}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">41</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top>　}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">42</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockEnd.gif" align=top>}</SPAN></SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN></DIV></FONT><BR><FONT size=2>本文的结��Z��是放之四���L(f��ng)��准的教条�Q�有时常识和�l�验才是最好的老师。如果你对自��q��做法没有癑ֈ�之百的信心，务必加上详细、全面的注释�?<BR><BR>　　另一斚w���Q�不要笑话这些错误，不妨问问你自己是否真地彻底摆�׃���q�些坏习(f��n)惯。即使最有经验的�E�序员偶��?d��ng)也会(x��)误入歧途，原因很简单，因�ؓ(f��)它们���确实实带来了“方侎쀝。所有这些反例都可以看作Java�~�程世界的恶��，它们���丽动�h�Q�无孔不入，时刻诱惑着你。也许有��Z��(x��)认�ؓ(f��)�q�些都属于鸡皮蒜毛的���事�Q�不���x��齿，但请��C���Q�勿以恶���而�ؓ(f��)之，勿以善小而不为�?</FONT><BR><img src ="http://www.aygfsteel.com/jorwen/aggbug/29425.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.aygfsteel.com/jorwen/" target="_blank">方佳�?/a> 2006-02-01 12:36 <a href="http://www.aygfsteel.com/jorwen/articles/29425.html#Feedback" target="_blank" style="text-decoration:none;">发表评论</a></div>]]></description></item><item><title>java多线�E�设计模�?/title><link>http://www.aygfsteel.com/jorwen/articles/29424.html</link><dc:creator>方佳�?/dc:creator><author>方佳�?/author><pubDate>Wed, 01 Feb 2006 04:34:00 GMT</pubDate><guid>http://www.aygfsteel.com/jorwen/articles/29424.html</guid><wfw:comment>http://www.aygfsteel.com/jorwen/comments/29424.html</wfw:comment><comments>http://www.aygfsteel.com/jorwen/articles/29424.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://www.aygfsteel.com/jorwen/comments/commentRss/29424.html</wfw:commentRss><trackback:ping>http://www.aygfsteel.com/jorwen/services/trackbacks/29424.html</trackback:ping><description><![CDATA[&nbsp;&nbsp;&nbsp;&nbsp; 摘要: java语言已经内置了多�U�程支持�Q�所有实现Runnable接口的类都可被启动一个新�U�程�Q�新�U�程�?x��)执行该实例的run()�Ҏ(gu��)���Q�当run()�Ҏ(gu��)��执行完毕后，�U�程���q��束了。一旦一个线�E�执行完毕，�q�个实例��׃��能再重新启动�Q�只能重新生成一个新实例�Q�再启动一个新�U�程。Thread�c�L��实现了Runnable接口的一个实例，它代表一个线�E�的实例�Q��ƈ且，启动�U�程的唯一�Ҏ(gu��)�����是通过Thread�cȝ��start()实例�?..&nbsp;&nbsp;<a href='http://www.aygfsteel.com/jorwen/articles/29424.html'>阅读全文</a><img src ="http://www.aygfsteel.com/jorwen/aggbug/29424.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.aygfsteel.com/jorwen/" target="_blank">方佳�?/a> 2006-02-01 12:34 <a href="http://www.aygfsteel.com/jorwen/articles/29424.html#Feedback" target="_blank" style="text-decoration:none;">发表评论</a></div>]]></description></item><item><title>中文字符串长度计��?/title><link>http://www.aygfsteel.com/jorwen/articles/29423.html</link><dc:creator>方佳�?/dc:creator><author>方佳�?/author><pubDate>Wed, 01 Feb 2006 04:30:00 GMT</pubDate><guid>http://www.aygfsteel.com/jorwen/articles/29423.html</guid><wfw:comment>http://www.aygfsteel.com/jorwen/comments/29423.html</wfw:comment><comments>http://www.aygfsteel.com/jorwen/articles/29423.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://www.aygfsteel.com/jorwen/comments/commentRss/29423.html</wfw:commentRss><trackback:ping>http://www.aygfsteel.com/jorwen/services/trackbacks/29423.html</trackback:ping><description><![CDATA[<P>&nbsp;</P>
<DIV style="BORDER-RIGHT: #cccccc 1px solid; PADDING-RIGHT: 5px; BORDER-TOP: #cccccc 1px solid; PADDING-LEFT: 4px; FONT-SIZE: 13px; PADDING-BOTTOM: 4px; BORDER-LEFT: #cccccc 1px solid; WIDTH: 98%; WORD-BREAK: break-all; PADDING-TOP: 4px; BORDER-BOTTOM: #cccccc 1px solid; BACKGROUND-COLOR: #eeeeee"><SPAN style="COLOR: #008080">&nbsp;1</SPAN><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top><SPAN style="COLOR: #0000ff">public</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">class</SPAN><SPAN style="COLOR: #000000">&nbsp;&nbsp;StringLengthTest<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;2</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_31_228_Open_Image onclick="this.style.display='none'; Codehighlighter1_31_228_Open_Text.style.display='none'; Codehighlighter1_31_228_Closed_Image.style.display='inline'; Codehighlighter1_31_228_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockStart.gif" align=top><IMG id=Codehighlighter1_31_228_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_31_228_Closed_Text.style.display='none'; Codehighlighter1_31_228_Open_Image.style.display='inline'; Codehighlighter1_31_228_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedBlock.gif" align=top></SPAN><SPAN id=Codehighlighter1_31_228_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_31_228_Open_Text><SPAN style="COLOR: #000000">{<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;3</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>&nbsp;&nbsp;&nbsp;&nbsp;</SPAN><SPAN style="COLOR: #0000ff">public</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">static</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #0000ff">void</SPAN><SPAN style="COLOR: #000000">&nbsp;main(String[]&nbsp;args)&nbsp;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;4</SPAN><SPAN style="COLOR: #000000"><IMG id=Codehighlighter1_81_226_Open_Image onclick="this.style.display='none'; Codehighlighter1_81_226_Open_Text.style.display='none'; Codehighlighter1_81_226_Closed_Image.style.display='inline'; Codehighlighter1_81_226_Closed_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockStart.gif" align=top><IMG id=Codehighlighter1_81_226_Closed_Image style="DISPLAY: none" onclick="this.style.display='none'; Codehighlighter1_81_226_Closed_Text.style.display='none'; Codehighlighter1_81_226_Open_Image.style.display='inline'; Codehighlighter1_81_226_Open_Text.style.display='inline';" src="http://www.aygfsteel.com/images/OutliningIndicators/ContractedSubBlock.gif" align=top>&nbsp;&nbsp;&nbsp;&nbsp;</SPAN><SPAN id=Codehighlighter1_81_226_Closed_Text style="BORDER-RIGHT: #808080 1px solid; BORDER-TOP: #808080 1px solid; DISPLAY: none; BORDER-LEFT: #808080 1px solid; BORDER-BOTTOM: #808080 1px solid; BACKGROUND-COLOR: #ffffff"><IMG src="http://www.aygfsteel.com/images/dot.gif"></SPAN><SPAN id=Codehighlighter1_81_226_Open_Text><SPAN style="COLOR: #000000">{<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;5</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;String&nbsp;s&nbsp;</SPAN><SPAN style="COLOR: #000000">=</SPAN><SPAN style="COLOR: #000000">&nbsp;</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">你好�?/SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">;<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;6</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;System.out.println(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">length1:&nbsp;</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">s.length());<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;7</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/InBlock.gif" align=top>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;System.out.println(</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">length2:&nbsp;</SPAN><SPAN style="COLOR: #000000">"</SPAN><SPAN style="COLOR: #000000">+</SPAN><SPAN style="COLOR: #000000">s.getBytes().length);<BR></SPAN><SPAN style="COLOR: #008080">&nbsp;8</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedSubBlockEnd.gif" align=top>&nbsp;&nbsp;&nbsp;&nbsp;}</SPAN></SPAN><SPAN style="COLOR: #000000"><BR></SPAN><SPAN style="COLOR: #008080">&nbsp;9</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/ExpandedBlockEnd.gif" align=top>}</SPAN></SPAN><SPAN style="COLOR: #000000"><BR></SPAN><SPAN style="COLOR: #008080">10</SPAN><SPAN style="COLOR: #000000"><IMG src="http://www.aygfsteel.com/images/OutliningIndicators/None.gif" align=top></SPAN></DIV>
<P><BR>E:\&gt;javac StringLengthTest.java<BR>E:\&gt;java StringLengthTest</P>
<P>length1: 3<BR>length2: 6<BR></P><img src ="http://www.aygfsteel.com/jorwen/aggbug/29423.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://www.aygfsteel.com/jorwen/" target="_blank">方佳�?/a> 2006-02-01 12:30 <a href="http://www.aygfsteel.com/jorwen/articles/29423.html#Feedback" target="_blank" style="text-decoration:none;">发表评论</a></div>]]></description></item></channel></rss>                                                                               <footer>
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