HashMap的用法（两种迭代方法案例）

package TestMap;
import java.util.*;
/**
 * Created by Administrator on 2017/5/5.
 */
public class Testpet {
    public static void main(String[] args) {
        Map pets = new HashMap();
        pets.put("旺旺", "企鹅");
        pets.put("欧欧", "雪瑞娜");
        pets.put("汤姆", "猫");
        pets.put("杰瑞", "老鼠");
        Set keys = pets.keySet();
       /*  迭代输出方法一
           Iterator it = keys.iterator();
           while (it.hasNext()) {
            String key = (String) it.next();
            String value = (String) pets.get(key);
            System.out.println(key + "\t\t" + value);
        }*/
       //方法二
        for (Object key:keys) {
            String value = (String) pets.get(key);
            System.out.println(key+"    "+value);
        }
    }

}

运行结果：

杰瑞    老鼠 旺旺    企鹅 欧欧    雪瑞娜 汤姆    猫