blocks|key|1327284|text|就我个人而言，我会尝试让|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1327285|do_stuff();
return+do_more_stuff();|code-block|syntax|javascript|1327286|部分符合更通用的格式，以便应用策略(作为模式)。|1327287|然后，您可以重构所有调用这种块的地方，以便它们可以调用更通用的块(其中捕获只放置一次)。|1327288|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Personally I'd try to make the 

<pre><code>do_stuff();
return do_more_stuff();
</code></pre>

part conform to a more general format in order to apply Strategy (as a pattern).

Then you can refactor all the places where you call this kind of block so that they can call a more generalized block (where the catches are laid out just once).

blocks|key|1112184|text|这取决于do_stuff和do_more_stuff抛出检查异常的原因。他们这样做是为了迫使用户处理异常吗？如果是，则您试图避免：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1112185|try+{
++++do_stuff();
++++return+do_more_stuff();
}+catch+(Exception+e)+{
++++handle_exception_via_rtti(e);
}|code-block|syntax|javascript|1112186|是一件好事。|1112187|如果您的代码只是捕获了Exception，而do_stuff和do_more_stuff后来添加了额外的异常，那么您可能永远不会知道这种更改以及您的代码现在可能出错的事实。|1112188|因此，您可能必须处理throwing+the+kitchen+sink并处理所有这些异常，除非这些方法可以切换为未检查的异常。|1112189|另一方面，如果这些方法抛出检查异常只是因为程序员懒于处理它们，只是想推卸责任，也许你从错误的角度看待这个问题。|1112190|entityMap|0|LINK|mutability|MUTABLE|url|http://today.java.net/pub/a/today/2006/04/06/exception-handling-antipatterns.html^0|4|8|D|D|0|0|0|B|9|M|8|V|D|0|A|P|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]|$9|13|A|14|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|16|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|17|8|@$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|O|3|P|5|6|7|1E|8|@]|D|@$9|1F|A|1G|1|1H]]|E|$]]|$1|Q|3|R|5|6|7|1I|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|1J|8|@]|D|@]|E|$]]]|T|$U|$5|V|W|X|E|$Y|Z]]]]

It depends of why the <code>do_stuff</code> and <code>do_more_stuff</code> throw the checked exceptions. Are they doing that to force the user to treat the exception? If yes, then you trying to avoid:

<pre><code>try {
 do_stuff();
 return do_more_stuff();
} catch (Exception e) {
 handle_exception_via_rtti(e);
}
</code></pre>

is a good thing.

If your code just catches <code>Exception</code>, and the <code>do_stuff</code> and <code>do_more_stuff</code> later add extra exceptions, you'll probably never know about the change and the fact that your code could now be wrong.

So you might have to deal with <a href="http://today.java.net/pub/a/today/2006/04/06/exception-handling-antipatterns.html" rel="nofollow noreferrer">throwing the kitchen sink</a> and treat all those exceptions, unless the methods could switch to unchecked exceptions.

On the other hand, if the methods are throwing checked exceptions just because the programmer was lazy in treating with them and just wanted to pass the buck, maybe you are looking at this from the wrong angle.

blocks|key|1112273|text|引入一个可以被子类化的泛型Action类怎么样：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1112274|public+class+Action+{
++++public+void+runWithHandlers()+throws+Exception+{
++++++++try+{
+++++++++++run();
++++++++}+catch+(UnsupportedEncodingException+e)+{
++++++++++++throw+CustomException.programmer_error(e);
++++++++}+catch+(ProtocolException+e)+{
++++++++++++throw+CustomException.programmer_error(e);
++++++++}+catch+(MalformedURLException+e)+{
++++++++++++throw+CustomException.programmer_error(e);
++++++++}+catch+(SocketTimeoutException+e)+{
++++++++++++throw+new+CustomException(e);
++++++++}+catch+(IOException+e)+{
++++++++++++throw+CustomException.unexpected_error(e);
++++++++}
++++}
++++public+void+run()+throws+Exception+{
++++++++//+TODO+subclasses+of+Action+must+implement+this
++++}
}|code-block|syntax|javascript|1112275|然后在代码中的其他地方，实例化Action的一个子类并调用runWithHandlers()：|1112276|new+MyAction().runWithHandlers();|1112277|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

How about introducing a generic Action class that can be subclassed:

<pre><code>public class Action {
 public void runWithHandlers() throws Exception {
 try {
 run();
 } catch (UnsupportedEncodingException e) {
 throw CustomException.programmer_error(e);
 } catch (ProtocolException e) {
 throw CustomException.programmer_error(e);
 } catch (MalformedURLException e) {
 throw CustomException.programmer_error(e);
 } catch (SocketTimeoutException e) {
 throw new CustomException(e);
 } catch (IOException e) {
 throw CustomException.unexpected_error(e);
 }
 }
 public void run() throws Exception {
 // TODO subclasses of Action must implement this
 }
}
</code></pre>

Then somewhere else in your code you instantiate one of the subclasses of Action and call runWithHandlers():

<pre><code>new MyAction().runWithHandlers();
</code></pre>

blocks|key|1112351|text|如果您负担得起Scala，请查看它:您可以在catch块中对异常进行模式匹配。参见Scala+for+Java+Refugees+Part+4:+Pattern+Matching+and+Exceptions。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1112352|entityMap|0|LINK|mutability|MUTABLE|url|http://www.codecommit.com/blog/scala/scala-for-java-refugees-part-4^0|15|1R|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

If you can afford Scala, check it out: you can pattern match the exception in the catch block. See <a href="http://www.codecommit.com/blog/scala/scala-for-java-refugees-part-4" rel="nofollow noreferrer">Scala for Java Refugees Part 4: Pattern Matching and Exceptions</a>.

I have this code:

<pre><code>try {
 do_stuff();
 return do_more_stuff();
} catch (UnsupportedEncodingException e) {
 throw CustomException.programmer_error(e);
} catch (ProtocolException e) {
 throw CustomException.programmer_error(e);
} catch (MalformedURLException e) {
 throw CustomException.programmer_error(e);
} catch (SocketTimeoutException e) {
 throw new CustomException(e);
} catch (IOException e) {
 throw CustomException.unexpected_error(e);
}
</code></pre>

I now need to have all those catch blocks in another similar function. What is the best way to avoid duplication here?

Note that the code inside the two try blocks is not very similar.

Also I can't really put the set of catches higher up.

Note, I'd prefer to avoid:

<pre><code>try {
 do_stuff();
 return do_more_stuff();
} catch (Exception e) {
 handle_exception_via_rtti(e);
}
</code></pre>

How to avoid duplicating complicated catch blocks

我有这样的代码：try {    do_stuff();    return do_more_stuff();} catch (UnsupportedEncodingException e) {    throw CustomException.programmer_error(e);} catch (Protocol...

问如何避免复制复杂的catch块
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