例子

package com.test.jhf_6_21.classwork;


import java.util.HashMap;
import java.util.Iterator;

import java.util.Map;

public class MapTest {

public static void main(String[] args) {
    Map<String, Object> map = new HashMap<String, Object>();

    map.put("小花", new Cat("波斯貓"));
    map.put("旺財", new Dog("中華田園犬"));
    map.put("大黑", new Dog("牧羊犬"));
    map.put("八戒", new Pig("荷蘭豬"));

    /*print(map);
    add(map, "啊黃", new Dog("大黃狗"));
    print(map);
    remove(map, "啊黃");
    print(map);
    change(map, "大黑", new Dog("德國牧羊犬"));
    print(map);*/
    show(map);
}

// 增
static void add(Map<String, Object> map, String key, Object Pet) {
    map.put(key, Pet);
}

// 刪
static boolean remove(Map<String, Object> map, Object key) {
    if (map.containsKey(key)) {
        map.remove(key);
        return true;
    } else {
        return false;
    }
}

// 查
static boolean search(Map<String, Object> map, Object key) {
    if (map.containsKey(key)) {
        return true;
    } else {
        return false;
    }
}

// 改
static boolean change(Map<String, Object> map, String key, Object Pet) {
    if (map.containsKey(key)) {
        map.remove(key);
        map.put(key, Pet);
        return true;
    } else {
        return false;
    }
}

// 迭代元素
static void print(Map<String, Object> map) {
    System.out.println(map.keySet() + "" + map.values());
    for (Object obj : map.keySet()) {
        System.out.print(obj + "\t");
        System.out.println(map.get(obj));
    }
}
static void show(Map<String, Object> map) {
    Iterator<String> it  = map.keySet().iterator();
    while (it.hasNext()) {

        Object Pet = map.get(it.next());
        System.out.println(Pet);
    }
}
 

}