java - 使用没有集合的泛型

Question

假设我有以下内容：

List<Apple> myList = new ArrayList<Apple>();

如果我想调用myList.add(myApple)，Java 期望 frommyApple具有类型Apple，而不是任何其他类型（当然子类除外）。但是，如果我想要一个对象 ( Blender) 并根据内部声明的类型具有不同的方法签名<>并且没有方法重载怎么办？像这样：

Blender<Apple> Tool = new Blender<Apple>();
Tool.blendIt(new Apple()); //expects to have only apples in here

Blender<Banana> OtherTool = new Blender<Banana>();
OtherTool.blendIt(new Banana()); //only Banana's are permitted

可能吗？

Answer 1

您正在寻找通用类。

class Blender<T>{
T t;
public void blendIt(T arg){
//stuff
}
}

class Test {
   public void method() {
     Blender<Apple> blendedApple = new Blender<Apple>();
     blendedApple.blendIt(new Apple()); 
     Blender<Bannana> blendedBannana = new Blender<Bannana>();     
     blendedBannana.blendIt(new Bannana());
   }
 }

Answer 2

是的：

public class Blender<T> {
   public void blendIt(T arg) { ... }
}

Answer 3

In Java generics are NOT just for Collections only. It is a general concept and applies to classes, methods, etc. You can create a generic class.