blocks|key|1680482|text|您可能会给JVM提供很多地方来搜索，这可能会在装入类时产生一些开销--我猜一个聪明的JVM会高效地完成这项工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1680483|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You are potentially giving the JVM a lot of places to search, this might give some overhead as classes are loaded - I guess a clever JVM will do this efficiently.

blocks|key|1676651|text|这样做可能会加载不需要的类，如果同一个库有两个版本，那么就是kaboom。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1676652|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You might load undesired classes by doing so, and if there is two versions of the same library; well, kaboom.

blocks|key|934533|text|如果这是你想做的，那就去做吧。只要你意识到后果。请记住，如果其他任何人必须维护项目，他们可能会将一堆jars文件复制到该文件夹中，而没有意识到默认情况下它们将被链接。不过，他们应该不会花太长时间来了解发生了什么。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|934534|我通常会尽量减少我使用的jar文件的数量，并手动将它们链接起来。我知道这是个人喜好。|934535|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

If it's what you want to do, then do it. As long as you are aware of the consequences. Keep in mind that if anyone else has to maintain the project, they may copy a bunch of jars into that folder not realizing that they'll be linked by default. It shouldn't take them too long to see what's going on, though.

I generally try to minimize the number of jar files I use, and link them all in manually. I realize this is personal preference.

blocks|key|1676679|text|显式的类路径可以作为什么库(以及可能是什么版本)的文档！应用程序依赖于。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1676680|如果你使用通配符，你就会失去这一点-如果它没有在其他地方记录，那么如果有人在没有lib文件夹的情况下获得了应用程序的副本(或者你意外地删除了它)，他们将很难通过重复运行应用程序，查看ClassNotFoundErrors并希望所有的库都使用合理的包名称来追踪所有的依赖项。|offset|length|style|CODE|1676681|entityMap^0|0|14|3|2J|I|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|I|$]]

An explicit classpath can server as a documentation of what libraries (and perhaps what versions thereof!) the application depends on.

You lose this if you use wildcards - if it's not documented elsewhere, then if someone gets a copy of the app without the <code>lib</code> folder (or you delete it accidentally), they'll have a very hard time tracking down all the dependencies via repeatedly running the app, looking at <code>ClassNotFoundError</code>s and hoping that all libraries used sensible package names.

blocks|key|932600|text|我的第一反应是不要使用env.CLASSPATH，但在考虑为什么不应该这样做的同时，我开始喜欢这个想法，至少在本地开发和测试环境中(至少在一段时间内)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|932601|这种方法的优点是，您可以保留一个本地文件夹，其中包含所有的通用库(log4j、dom4j、joda+time、谷歌集合、apache+commons+zoo等)。因此，您可以从shell编译和执行所有应用程序，而无需浪费时间键入冗长的类路径参数。|932602|而且您仍然可以自由地使用-cp参数，因为它取代了全局CLASSPATH设置。|offset|length|style|CODE|932603|我永远不会在生产系统上使用它。如果有人更改了该文件夹或CLASSPATH变量的内容，我的应用程序就不能正常工作，这样的风险太高了。|932604|因此，对于生产环境，在类路径字符串中没有全局'+classpath‘和通配符。|932605|在类似于上面的环境中使用通配符路径的一个缺点是:过一段时间后，太多的项目依赖于单个库文件夹。您不知道更新库或删除旧库的副作用。对于大型应用程序，可能很难找出池中的哪些库是真正需要的。您最终可能会将未使用的库添加到产品中，因为您不确定应用程序是否可以在没有库的情况下运行。|932606|所以我的结论是--这是开发、测试、原型开发的捷径，但对于生产来说是有风险的。对于生产环境，我更喜欢(自动生成的)不带通配符的类路径字符串。|932607|entityMap^0|0|0|C|3|Q|9|0|R|9|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|V|8|@$F|W|G|X|H|I]|$F|Y|G|Z|H|I]]|9|@]|A|$]]|$1|J|3|K|5|6|7|10|8|@$F|11|G|12|H|I]]|9|@]|A|$]]|$1|L|3|M|5|6|7|13|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|14|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|15|8|@]|9|@]|A|$]]|$1|R|3|-4|5|6|7|16|8|@]|9|@]|A|$]]]|S|$]]

My first reflex was don't use env.CLASSPATH, but on second thought and while thinking about why one shouldn't do it I started likeing the idea, at least for a local development and test environment (and at least for a while)

The advantage of this approach is that you can keep a local folder with all your common libraries (log4j, dom4j, joda time, google collections, the apache commons zoo, ...). So you can compile and execute all your applications from the shell without wasting time typing long classpath arguments.

And your still free to use a <code>-cp</code> argument, because it replaces the global <code>CLASSPATH</code> setting.

I would never use it on a production system. The risk is just to high that someone changes the content of that folder or the <code>CLASSPATH</code> variable and my application doesn't work anymore.

So for production, no global 'CLASSPATH' and no wildcards in the classpath string.

A disadvantage of using the wildcard path in an environment like above: After a while too many projects depend upon the single library folder. You don't know the sideeffects of updating a library or deleting an old one. And for large application it might be hard to find out which libraries from the pool are really needed. You might end up adding unused libs to the product just because you're unsure if the application will run without that lib.

So my conclusion - a nice shortcut for development, testing, prototyping but risky for production. For production I'd prefer (autogenerated) classpath strings without wildcards.

Are there any disadvantages in using Java 6 wildcards in my <a href="http://download.oracle.com/javase/6/docs/technotes/tools/windows/classpath.html" rel="nofollow noreferrer">classpath</a> ? e.g.

<pre><code>C:&gt; set CLASSPATH=.\lib\*
</code></pre>

I can see that where there are two jars that both contain a class with the same path then using a wildcard may lead to results that are hard to track down.

But other than that, is there anything else to be aware of?

Why would I not use a wildcard in my classpath?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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在我的中使用Java6通配符有什么缺点吗？例如：C:> set CLASSPATH=.\lib\*我可以看到，如果有两个jars都包含具有相同路径的类，那么使用通配符可能会导致难以跟踪的结果。但除此之外，还有什么需要注意的吗？

问为什么我不能在类路径中使用通配符？
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问为什么我不能在类路径中使用通配符？EN