java - 检查Java中对象的子类

Question

这个问题已经有答案了:

How to check if a subclass is an instance of a class at runtime? [duplicate] (7 个回答)

已关闭 7 年前。

考虑类 MinorClassA和MinorClassB ，都延伸MajorClass 。我有一个对象 MajorClass我确信它实际上是其子类之一的实例。

MinorClassA subclassedObj = new MinorClassA();
MajorClass obj = subclassedObj;

//------ More code -------------

if( subclassof(obj) == MinorClassA) //Something like this

如何找出该对象的子类是什么？我无权访问 subclassedObj ，仅限obj .

编辑澄清:我知道如何检查是否 MinorClassA是 MajorClass 的实例，但反之则不然。

Answer 1

听起来你想要 instanceof operator:

At run time, the result of the instanceof operator is true if the value of the RelationalExpression is not null and the reference could be cast to the ReferenceType without raising a ClassCastException. Otherwise the result is false.

所以在你的情况下:

if (obj instanceof MinorClassA) {
    ...
}