java中Map集合4种遍历方式

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", "我已上了年纪啦");// 4种迭代方法// 第一种System.out.println("第一种");for (Entry<String, Object> entry : map.entrySet()) {System.out.println("Key = " + entry.getKey() + ", Value = "+ entry.getValue());}// 第二种//使用迭代器System.out.println("第二种");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());}// 第三种System.out.println("第三种");for (String key : map.keySet()) {System.out.println("Key = " + key + ",Value = " + map.get(key));}// 第四种System.out.println("第四种");//使用迭代器for (Iterator<String> ite = map.keySet().iterator(); ite.hasNext();) {String key = ite.next();System.out.println("Key = " + key + ",Value = " + map.get(key));}}}