�??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>&#20122;&#27954;&#65;&#8548;&#27704;&#20037;&#26080;&#30721;&#31934;&#21697;&#65;&#65;&#44;&#20122;&#27954;&#118;&#97;&#22312;&#32447;&#118;&#97;&#22825;&#22530;&#118;&#97;&#19981;&#21345;&#19979;&#36733;&#44;&#20122;&#27954;&#25104;&#65;&#86;&#20154;&#24433;&#29255;&#22312;&#32447;&#35266;&#30475;</title><link>http://m.tkk7.com/phoenixtoday/category/25066.html</link><description>每天�q�步一点点�Q�努力做好自�?/description><language>zh-cn</language><lastBuildDate>Wed, 09 Jan 2008 22:55:45 GMT</lastBuildDate><pubDate>Wed, 09 Jan 2008 22:55:45 GMT</pubDate><ttl>60</ttl><item><title>一炚w��构心�?/title><link>http://m.tkk7.com/phoenixtoday/archive/2008/01/08/173844.html</link><dc:creator>朱雀</dc:creator><author>朱雀</author><pubDate>Tue, 08 Jan 2008 15:56:00 GMT</pubDate><guid>http://m.tkk7.com/phoenixtoday/archive/2008/01/08/173844.html</guid><wfw:comment>http://m.tkk7.com/phoenixtoday/comments/173844.html</wfw:comment><comments>http://m.tkk7.com/phoenixtoday/archive/2008/01/08/173844.html#Feedback</comments><slash:comments>0</slash:comments><wfw:commentRss>http://m.tkk7.com/phoenixtoday/comments/commentRss/173844.html</wfw:commentRss><trackback:ping>http://m.tkk7.com/phoenixtoday/services/trackbacks/173844.html</trackback:ping><description><![CDATA[昨天�Q�要写一�D늨�序完成一个定时�Q务，是有关Socket 发送的。胖子给我发了一�D늎�成的�E�序�Q�这�D늨�序基本上的功能是实现了，但是表达的�ƈ不是那么清晰�Q�因此我想重构一下。没惛_��重构的过�E�竟然花了一个多���时�Q�从晚上八点多，一下就写到了十点，但是重构完后�Q�感觉清晰多了。仔�l�想��x��获颇多，因此在这里写写经验进行�ȝ���?br />
<br />
重构�E�序的目的，不是因�ؓ�E�序不能用才要你去重构，重构的目的是因�ؓ一、你的代码，被�h看的�ơ数�Q�远比它用到的次数多�Q�二、重构有利于你发现问题，让你的程序结构优化，因此可复用性更强，遵守了知识的唯一性，DRY 原则�Q�三、如果你要改动这�D�代码，那么先重构，使得你的代码好改�Q�这实际是在��Z��的未来减���工作量�Q�而且一�D�优�U�的代码，带给你的价��|���q�比你每�ơ都要Ctrl+C�Q�Ctrl+V 大得多�?br />
<br />
写代码，要让你的代码�W�一�ơ呈现在别�h面前的时候，像读��p��一般，那么你的代码功底是��够了。你的代码就可以�U�C��你最好的文档了，其余什么文���，大可不必�Q?br />
<br />
��Z��昨天的经验，我新�ȝ��了两条：<br />
一、经�怋�用重构方法extract method 的�h�Q�会发现�Q���L��可以省掉一些��时变量。这是好事，但这可能会造成如下的结果：<br />
<br />
<span style="background-color: #b8c2af;">method_one(method_two(method_three(method_four())))</span><br />
<br />
也就是说�Q�很可能会导致这�U�长串的嵌套�Q�导致程序可��L��的下降�Q���人看的晕头�{向。那么如何解军_���Q�其实是一个度的问题。我�l�自己定了一个规矩，临界�Ҏ��三个函数�q�样�U�联��h���Q�如果超�q�三个，我就���它们拆开。比如说上面�q�个���例子，我会拆成�Q?br />
<br />
<span style="background-color: #b8c2af;">
arg = method_three(method(four));</span><br />
<span style="background-color: #b8c2af;">method_one(method_two(arg));</span><br />
<br />
虽然���费了一个��时变量，但是�q�样���可以让��Z��眼看懂我的意思，可读性提升，修改��h��自然也会�Ҏ��些�?br />
<br />
二、写�q�Java I/O 的�h�Q�肯定看到过�q�样的程序：<br />
<br />
<span style="background-color: #b8c2af;">
Reader in = null;<br />
Writer out = null;<br />
try<br />
{<br />
&nbsp;&nbsp;&nbsp; in = new InputStreamReader(socket.getInputStream(),"utf8");<br />
&nbsp;&nbsp;&nbsp; out = new OutputStreamWriter(socket.getOutputStream(),"utf8");<br />
<br />
/**<br />
&nbsp;* some TODOs here<br />
&nbsp;*<br />
**/<br />
}catch(IOException ioe)<br />
{<br />
&nbsp;&nbsp;&nbsp; System.err.println("error message");<br />
&nbsp;&nbsp;&nbsp; ioe.printStackTrace();<br />
}<br />
finally<br />
{<br />
&nbsp;&nbsp; try<br />
&nbsp;&nbsp;&nbsp; {<br />
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; if(in != null)<br />
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;  &nbsp;&nbsp;&nbsp; in.close();<br />
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; if(out != null)<br />
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;  &nbsp;&nbsp;&nbsp; out.close();<br />
&nbsp;&nbsp;&nbsp; }catch(IOException ioe2)<br />
&nbsp;&nbsp;&nbsp; {<br />
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;  System.err.println("some error message");<br />
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;  ioe2.printStackTrace();<br />
&nbsp;&nbsp;&nbsp; }<br />
}</span><br />
<br />
怎么说呢�Q�这�D�代码看上去�Q�其实是够好了，其实不重构也是可以的。也许我偏执吧，我认为它不够好，因�ؓ�Q�首先，大段的try catch 的确会捕获异常，但是�q�段代码臛_��有好几段是会独立抛出异常的，�q�里包含了四个IO 实例的创建和销毁，�q�四�D�代码如果出错都会抛出异常，那么你捕��L��到底是哪个呢�Q�其�ơ，没有把功能段合理分开�Q�这�D�代码的逻辑功能实际上是两个�Q�一个是读，一个是写，那么合�ƈ在一��P��首先��序很�ؕ�Q�其�ơ容易让阅读的�h产生困惑�Q�从而造成代码可读性差。我是这样做的：<br />
<br />
<span style="background-color: #b8c2af;">
private void writeFile(String fileName, String outStr)<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp; Writer writer = null;<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;try<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;writer = new OutputStreamWriter(new FileOutputStream(fileName),<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;"utf8");<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;catch (UnsupportedEncodingException e)<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;System.err.println("不支持的�~�码方式");<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;e.printStackTrace();<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;catch (FileNotFoundException e)<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;System.err.println("初始化文件失败，或�\径不存在�Q? + fileName);<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;e.printStackTrace();<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;try<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;writer.write(outStr);<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;writer.flush();<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;catch (IOException e)<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;System.err.println("写文件失�?);<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;e.printStackTrace();<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;finally<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;try<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;  &nbsp;&nbsp;  &nbsp;&nbsp;  &nbsp;&nbsp;  &nbsp;&nbsp;&nbsp;  if(writer != null)<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp; writer.close();<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;catch (IOException e)<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;{<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;System.err.println("关闭文�g��p�|");<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;e.printStackTrace();<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}<br />
<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}<br />
&nbsp;&nbsp; &nbsp;&nbsp;&nbsp; &nbsp;}</span><br />
<br />
�c�M��的，也将�ȝ��逻辑独立抽出来，虽然�Q�这不但没��代码的量减少�Q�却增加了很多try catch 模块�Q�不�q�逻辑上很完整�Q�而且发挥了每个try catch 的最佛_��效。我把它起名曎ͼ�我个人的偏执情节吧�?br />
<br />
��C���Q�要睡觉了，本来�q�想���代码从最初模��P��到最后模��L���q�程复述一遍，改天有机会再��_���_�֍�都已�l�说了。嘿�?br />
<br />
<img src ="http://m.tkk7.com/phoenixtoday/aggbug/173844.html" width = "1" height = "1" /><br><br><div align=right><a style="text-decoration:none;" href="http://m.tkk7.com/phoenixtoday/" target="_blank">朱雀</a> 2008-01-08 23:56 <a href="http://m.tkk7.com/phoenixtoday/archive/2008/01/08/173844.html#Feedback" target="_blank" style="text-decoration:none;">发表评论</a></div>]]></description></item></channel></rss>            <footer>
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