blocks|key|588318|text|使用$访问内部类|type|unstyled|depth|inlineStyleRanges|entityRanges|data|588319|java.nio.channels.FileChannel$MapMode/READ_ONLY|code-block|syntax|javascript|588320|请注意，如果您正在导入FileChannel，您也应该导入FileChannel$MapMode。|offset|length|style|CODE|588321|entityMap^0|0|0|B|B|T|J|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]|$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|N|$]]

You access inner classes with $

<pre><code>java.nio.channels.FileChannel$MapMode/READ_ONLY
</code></pre>

Mind that if you are importing <code>FileChannel</code> you should also import <code>FileChannel$MapMode</code>.

blocks|key|588381|text|语法(FileChannel/MapMode)是一种简化，仅用于静态字段和方法(对于字段，您甚至可以省略括号)！此外，.和..表单是针对字段/方法的，而不是针对嵌套/内部类的！|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|588382|对于JVM，内部类Outer.Inner只是一个名为Outer$Inner的类(编译器为此创建了一个文件Outer$Inner.class+)。Java编译器允许您通过Outer.Inner引用它。您还可以定义一个名为Outer$Inner的非内部类，编译器允许您将其引用为Outer$Inner。但是，您不能同时定义这两个文件，因为两者的类名都是Outer$Inner+(以及名为Outer$Inner.class的.class文件，因此这将是一个重复的类名！)|588383|当使用反射时-例如使用Class.forName()+-(通常是为了引入一些动态性)，你不能省略导入类的包名，你必须使用带有$符号而不是点的真实类名。|588384|可能是因为它的动态特性，Clojure采用了相同的方法，所以如果类是my.package格式的，那么就需要使用表单my.package.Outer$Inner+--即使您已经导入了外部类！为了避免包名，您可以显式地导入内部类my.package.Outer$Inner，然后将其引用为Outer$Inner+(它的真实类名！)但您不能通过简单地导入它来将其缩减为Inner：|588385|Inner对Java虚拟机没有任何意义，只是Java编译器从编译时上下文为您提供了这个快捷方式(这对于Java虚拟机和像Class.forName这样的方法在运行时是不可用的！)+...当然，在Clojure中，你总是可以定义：(def+Inner+Outer$Inner)+...或者(def+Tom+Outer$Inner)或者(def+Harry+Outer$Inner)或者其他什么..。如果你更喜欢的话。|588386|entityMap^0|2|L|1N|1|1P|2|0|9|B|Q|B|1G|H|2C|B|31|B|3T|B|4U|B|5B|H|5T|6|0|B|F|1Q|1|0|Y|A|1L|M|34|M|3Y|B|51|5|0|0|5|1O|D|36|N|3Z|L|4M|N|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]|$9|19|A|1A|B|C]|$9|1B|A|1C|B|C]|$9|1D|A|1E|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|1F|8|@$9|1G|A|1H|B|C]|$9|1I|A|1J|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|1K|8|@$9|1L|A|1M|B|C]|$9|1N|A|1O|B|C]|$9|1P|A|1Q|B|C]|$9|1R|A|1S|B|C]|$9|1T|A|1U|B|C]]|D|@]|E|$]]|$1|L|3|M|5|6|7|1V|8|@$9|1W|A|1X|B|C]|$9|1Y|A|1Z|B|C]|$9|20|A|21|B|C]|$9|22|A|23|B|C]|$9|24|A|25|B|C]]|D|@]|E|$]]|$1|N|3|-4|5|6|7|26|8|@]|D|@]|E|$]]]|O|$]]

The syntax <code>(FileChannel/MapMode)</code> is a simplification and intended only for static fields and methods (for fields, you may even omit the parentheses)! Also the <code>.</code> and <code>..</code> forms are for fields/methods but NOT for nested/inner classes!

For the JVM, an inner class <code>Outer.Inner</code> is just a class named <code>Outer$Inner</code> (and the compiler creates a file <code>Outer$Inner.class</code> for this). The Java compiler lets you refer to it by <code>Outer.Inner</code>. You can also define a not-inner class named <code>Outer$Inner</code> to which the compiler lets you refer as <code>Outer$Inner</code>. You cannot define both at the same time, however, since both would have class names of <code>Outer$Inner</code> (and <code>.class</code> files named <code>Outer$Inner.class</code>, so this would be a duplicate class name!)

When using reflection - e.g. with <code>Class.forName()</code> - (usually to introduce some dynamicity) you cannot omit the package name of an imported class and you must use the real class name with the <code>$</code> sign instead of a dot.

Probably for its dynamic nature, Clojure takes the same approach, so you need to use the form <code>my.package.Outer$Inner</code> if the class is in <code>my.package</code> - even if you imported the outer class already! To avoid the package name, you can explicitly import the inner class <code>my.package.Outer$Inner</code> and then refer to it as <code>Outer$Inner</code> (its real class name!) but you will not reduce this to <code>Inner</code> by just importing it:

<code>Inner</code> has no meaning to the JVM, just the Java-Compiler offers you this shortcut from the compile time context (which is NOT available to the JVM and methods like <code>Class.forName</code> at runtime!) ... OK, in Clojure you could, of course, always define: <code>(def Inner Outer$Inner)</code> ... or <code>(def Tom Outer$Inner)</code> or <code>(def Harry Outer$Inner)</code> or whatever ... if you like that better.

Basically what I need to do is this

<pre><code>FileChannel.MapMode.READ_ONLY
</code></pre>

I tried doing the obvious

<pre><code>(.. FileChannel MapMode READ_ONLY)
</code></pre>

but that ends up throwing an exception 

<pre><code>java.lang.NoSuchFieldException: MapMode
</code></pre>

even the <code>/</code> notation specified as for access static fields in the <a href="http://clojure.org/java_interop" rel="noreferrer">interop documentation</a> produces the same exception

<pre><code>(. (FileChannel/MapMode) READ_ONLY)
</code></pre>

How to access static inner Java class via Clojure interop?

虚拟机

编译器

Java

基本上我需要做的是FileChannel.MapMode.READ_ONLY我试着做一些显而易见的事情(.. FileChannel MapMode READ_ONLY)但这最终抛出了一个异常java.lang.NoSuchFieldException: MapMode即使在中为访问静态字段指定的/表示法也会产生相同的...

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