java中调用超类的抽象方法是否有效
..如果是的话，行为是什么？ 我在最近查看的一些代码中发现了这一点，这让我感到非常困惑。我没有java编译器，所以我自己无法轻易回答这个问题。这是我正在谈论的内容的粗略示例。我预计这个结果会导致编译错误，但据我所知，它来自工作代码库。
abstract class Base {
...
abstract boolean foo(String arg);
}
class Sub extends Base {
...
boolean foo(String arg) {
if(condition)
return true;
else
return super.foo(arg); //<-- <boggle/>
}
}
..and if so what is the behavior?
I came across this in some code I was looking at recently, and it is very confusing to me. I don't have a java compiler, so I can't answer this easily myself. Here is the rough example of what I'm talking about. I would expect this result in a compile error, but as far as I know it is from a working code base.
abstract class Base {
...
abstract boolean foo(String arg);
}
class Sub extends Base {
...
boolean foo(String arg) {
if(condition)
return true;
else
return super.foo(arg); //<-- <boggle/>
}
}
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不，如果它在超类中是抽象的，你就不能调用它。尝试编译您的代码（已修复其他代码）会出现以下错误：
No, if it's abstract in the superclass you can't call it. Trying to compile your code (having fixed the others) gives this error:
当你输入“超级”时。在方法名称之前，你对编译器说：'嘿伙计！调用完全在基类中实现的方法'。它实际上并不存在，因此无法调用它并且编译器会抱怨。只需删除“超级”即可。并留下'foo(arg);'仅有的。这将告诉编译器在某个子类中寻找实现。
顺便说一句，如果您的示例中的条件始终为假，它将进入不定式循环并因内存不足而崩溃:)
干杯，~r
When you put 'super.' before the method name, you say to compiler: 'hey man! call the method implemented exactly in the Base class'. It doesn't exist there actually so it cannot be called and compiler complains. Just remove 'super.' and leave 'foo(arg);' only. This which will tell the compiler to look for a implementation in some subclass.
BTW, if condition in your example is always false, it'll get into infinitive loop and crash because of out of memory :)
Cheers, ~r
那不会编译。您无法调用抽象方法。
That won't compile. You can't invoke an abstract method.
将您的示例放入 Eclipse 中并对其进行编辑，使其实际上编译到此为止会产生以下错误：
“无法直接调用 Base 类型的抽象方法 foo(String)”
您确定它来自“工作代码库吗？”
Tossing your example into Eclipse and editing it so it actually compiles that far produces this error:
"Cannot directly invoke the abstract method foo(String) for the type Base"
Are you sure that comes from a "working code base?"
抽象方法不能被调用，因为它只是一个声明类型，没有定义就没有必要调用它。这样编译时就会出现异常
Abstract method can't be called as it is just a declaration type, without a definition there is no point calling it. Thus Compile time Exception will occur