这两种方式在Java中投射有什么区别？ [英] What is the difference between these two ways of casting in Java?

问题描述

这两种投放方式在Java中有什么区别？

What is the difference between these two ways of casting in Java?

1. （CastingClass） objectToCast;

CastingClass.class.cast（objectToCast）;

Class＃cast（Object）的来源如下：

public T cast(Object obj) {
if (obj != null && !isInstance(obj))
    throw new ClassCastException();
return (T) obj;
}

因此， cast 基本上是一个泛型包装的cast操作，但我还是不明白为什么你需要一个方法。

So, cast is basically a generic wrapper of the cast operation, but I still don't understand why you would need a method for it.

推荐答案

你只能使用第一种形式的静态链接类。

You can only use the first form for statically linked classes.

在很多情况下，这是不够的 - 例如，你可能已经获得类实例使用反射或它被传递以你的方法作为参数;因此第二种形式。

In many cases that's not enough - for example, you may have obtained class instance using reflection or it was passed to your method as parameter; hence the second form.

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