package chapter6;

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

public class Example15 {
    public static void main(String[] args) {
        HashMap map = new HashMap(); // 创建Map对象
        map.put("2","李四");          //存储键和值
        map.put("3","王五");
        map.put("1","张三");

        // 方法一
        Set keySet = map.keySet();      //获取键的集合
        Iterator it = keySet.iterator();//选代键的集合
        while (it.hasNext()) {
            Object key = it.next();
            Object value = map.get(key); //获取每个键所对应的值
            System.out.println(key + ":" + value);
        }

        Iterator it2 = map.keySet().iterator();
        while (it2.hasNext()) {
            Object key = it2.next();
            System.out.println(key);
        }

        Iterator it3 = map.values().iterator();
        while (it3.hasNext()) {
            Object value = it3.next();
            System.out.println(value);
        }

        // 方法二
        Set entrySet = map.entrySet();          // 获取所有映射关系
        Iterator it4 = entrySet.iterator();   // 获取Iterator对象
        while (it4.hasNext()){
            //获取集合中键值对映射关系
            Map.Entry entry = (Map.Entry) (it4.next());
            Object key = entry.getKey();//获取Entry中的键
            Object value = entry.getValue();//获取Entry中的值
            System.out.println(key + ":" + value);
        }

        for (Object obj : map.entrySet()) {
            System.out.println(obj);
        }

    }
}