有什么方法来确定什么类型的类是Java中的一个实例? [英] Is there a way to determine what type a class is an instance of in Java?
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问题描述
说我有3个类:
class A {}
class B extends A {}
class C extends A {}
然后可以确定特定对象是否 A
, B
或 C
? / p>
我认为这样的东西可能工作:
if .getClass()。isInstance(B.class)){
//为B
做某事} else(myObject.getClass()。isInstance(C.class)){
//为C
执行操作} else {
//为A
执行操作}
但是在阅读一点后,我认为它总是评价为B,因为它只是测试一个转换是否会工作,并且它们之间没有实质性的差异。
解决方案
这样做:
if(myObject instanceof B){
//做一些B
} else(myObject instanceof C){
//为C
做一些事情} else {
//为A
做一些事情}
Say I have 3 classes like so:
class A {}
class B extends A {}
class C extends A {}
Would it then be possible to determine whether a particular object was an instance of A
, B
, or C
?
I thought that something like this might work:
if (myObject.getClass().isInstance(B.class)) {
// do something for B
} else (myObject.getClass().isInstance(C.class)) {
// do something for C
} else {
// do something for A
}
but after reading a little I think it would always evaluate as B since it's just testing if a cast would work and there's no substantial differences between them.
解决方案
Do this:
if (myObject instanceof B) {
// do something for B
} else (myObject instanceof C) {
// do something for C
} else {
// do something for A
}
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