[英]Java generic type for objects
In Objective-C we have a generic type for objects called "id". 在Objective-C中,我们有一个通用类型的对象称为“ id”。
id someObject = someValue;
if([someObject isKindOfClass:[NSString class]]) {
NSString *string = someObject;
}
I want to know if there's something like that in Java. 我想知道Java中是否有类似的东西。
id someObject = someValue;
if(someObject instanceof String) {
String string = someObject;
}
Unless I'm missing something, you were very close to the answer yourself: 除非我缺少任何东西,否则您自己就很接近答案:
// obtain your object from somewhere
Object someObject = obtainObjectInstance();
// if it's a string...
if(someObject instanceof String) {
// cast and assign to some variable
String string = (String)someObject;
}
As a side note, all object instances contain information about the object's class: someObject.getClass()
附带说明一下,所有对象实例都包含有关对象类的信息: someObject.getClass()
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