JAVA学习笔记(二十五) - 泛型Generic

泛型Generic

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

/*
 * 泛型Generic
 * 泛型集合：即声明集合时指定集合中元素的类型
 * 
 */
public class Test02
{
    public static void main(String[] args)
    {
        test3();
    }

    public static void test1()
    {
        // 创建泛型集合，保存整数
        List<Integer> list = new ArrayList<Integer>();
        list.add(12);
        list.add(250);
        list.add(13);
        // 遍历集合
        for (Integer i : list)
        {
            System.out.println(i);
        }
    }

    public static void test2()
    {
        // 创建泛型集合，保存狗狗信息
        List<Dog> dogs = new ArrayList<Dog>();
        dogs.add(new Dog("小涛", "雄", 85));
        dogs.add(new Dog("程程", "雌", 13));
        dogs.add(new Dog("笑笑", "雄", 23));
        // 遍历集合
        for (int i = 0; i < dogs.size(); i++)
        {
            Dog dog = dogs.get(i);// 返回Dog对象
            System.out.println(dog);
        }

        // 泛型迭代器Iterator
        Iterator<Dog> it = dogs.iterator();
        while (it.hasNext())
        {
            Dog dog = it.next();// 直接返回Dog对象，无需做类型转换
            System.out.println(dog);
        }
    }

    public static void test3()
    {
        // 创建泛型Map集合
        Map<Integer, Dog> dogs = new HashMap<Integer, Dog>();
        dogs.put(001, new Dog("军子", "雄", 50));
        dogs.put(007, new Dog("超子", "雌", 78));

        Set<Integer> keys=dogs.keySet();
        Iterator<Integer> it=keys.iterator();
        while(it.hasNext()){
            int id=it.next();
            Dog dog=dogs.get(id);
            System.out.println("编号："+id+",信息："+dog.toString());
        }
    }
}

/*
 * 狗狗类
 */
public class Dog extends Pet
{
    String brand;// 品种

    public Dog(String name, String sex, int health)
    {
        super(name, sex, health);
    }

    public Dog(String name, String sex, int health, String brand)
    {
        this(name, sex, health);
        this.brand = brand;
    }

    // 重写父类的show方法
    public void show()
    {
        System.out.println("姓名：" + name + ",性别：" + sex + ",健康值：" + health
                + ",品种：" + brand);
    }

    // 重写父类的play方法
    public void play()
    {
        System.out.println("正在接飞盘。。。。");
        health = health + 5;
    }

    public String toString()
    {
        return "Dog[name=" + name + ",sex=" + sex + ",health=" + health + "]";
    }
}