泛型通配符＜?＞使用演示

package _5_30;

 

 

public class WildCardTest {

public static void main(String[] args) {

Box<String> name = new Box<String>("Hello");

Box<Integer> age = new Box<Integer>(12);

Box<Double> number = new Box<Double>(210.50);

 

getData(name);

getData(age);

getData(number);

}

 

public static void getData(Box<?> data) {

System.out.println("data: " + data.getData());

}

}

 

class Box<T> {

private T data;

 

public Box(T data) {

this.data = data;

}

 

public T getData() {

return data;

}

}