从Java的许多子类中确定子类
我有一个接口 Tree 和一个实现该接口的抽象类 RBTree。我还有几个类 Tree1...Tree9 扩展了这个抽象类。
我编写了一个测试单元，我想做这样的事情：
public void testRandom(RBTree tree){
for(int i = 0; i < 10; i++){
rbTree = new Tree1(); //if the tree in the parameter was of instance Tree1
rbTree = new Tree2(); //if the tree in the parameter was of instance Tree2
//etc.
/**
* do something with rbTree
*/
}
}
是否可以在不使用带有大量实例的 if 语句（或开关）链的情况下执行此操作？ ()？
（注意：我无法改变设计的任何内容，我知道这并不是真正的最佳选择）
I have an interface Tree and an abstract class RBTree which implements this interface. I also have several classes Tree1...Tree9 which extend this abstract class.
I've written a test unit where i want to do something like this:
public void testRandom(RBTree tree){
for(int i = 0; i < 10; i++){
rbTree = new Tree1(); //if the tree in the parameter was of instance Tree1
rbTree = new Tree2(); //if the tree in the parameter was of instance Tree2
//etc.
/**
* do something with rbTree
*/
}
}
Is it possible to do this without using a chain of if-statements (or a switch) with a lot of instanceof() ?
(note: i can't change anything about the design, i know it's not really optimal)
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您可以使用tree.getClass().newInstance()。
如果您想要一些比实例化更复杂的逻辑，您要么需要 instanceof 方法，要么更好 - 让每个 RBTree 子类都有一个执行该逻辑的方法（并使该方法在 <代码>RBTree)
You can use
tree.getClass().newInstance().In case you want to have some more complex logic than instantiation, you would either need the instanceof approach, or better - make each
RBTreesubclass have a method that performs that logic (and make that method abstract inRBTree)试试这个：
Try this:
使用反射，您可以：
问题是，如果实际实现有不同的方法等，您将无法访问它们。
Using reflection, you can:
Problem is that if the actual implementations have different methods etc. you won't be able to access them.