java中Map集合4種周遊方式

package com.liuyc;

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

public class MapTest {
	public static void main(String[] args) {
		Map<String, Object> map = new HashMap<String, Object>();
		map.put("name", "小明");
		map.put("age", 39);
		map.put("gender", "男");
		map.put("des", "我已上了年紀啦");

		// 4種疊代方法

		// 第一種
		System.out.println("第一種");
		for (Entry<String, Object> entry : map.entrySet()) {

			System.out.println("Key = " + entry.getKey() + ", Value = "+ entry.getValue());

		}
		// 第二種
		//使用疊代器
		System.out.println("第二種");
		for (Iterator<Entry<String, Object>> entryIte = map.entrySet().iterator(); entryIte.hasNext();) {
			Entry<String, Object> entry = entryIte.next();
			System.out.println("Key = " + entry.getKey() + ", Value = "+ entry.getValue());

		}
		// 第三種
		System.out.println("第三種");
		for (String key : map.keySet()) {

			System.out.println("Key = " + key + ",Value = " + map.get(key));

		}

		// 第四種
		System.out.println("第四種");
		//使用疊代器
		for (Iterator<String> ite = map.keySet().iterator(); ite.hasNext();) {
			String key = ite.next();
			System.out.println("Key = " + key + ",Value = " + map.get(key));
			
		}
		
	}
}