泛型

package GmDemo;public class GmDemo {/** * 泛型演示 */public static void main(String[] args) {Shop<Food> food = new Shop<Food>(new Food[] { new Food() });Shop<Pet> pet = new Shop<Pet>(new Pet[] { new Pet() });System.out.println(food.buy(0) + " " + pet.buy(0));}}class Food {@Overridepublic String toString() {return "食品";}}class Pet {@Overridepublic String toString() {return "宠物";}}class Shop<P> {// P的类型由调用者指定P[] products;public Shop(P[] products) {this.products = products;}P buy(int i) {return products[i];}}