java,map遍历，输出键值

import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;public class Test {/** * @param args */public static void main(String[] args) {// TODO Auto-generated method stubHashMap hashmap = new HashMap();hashmap.put("key1", "val1");hashmap.put("key2", "val2");hashmap.put("key3", "val3");Set set = hashmap.entrySet();/// 返回此映射所包含的映射关系的 Set 视图。Iterator iterator = set.iterator();while (iterator.hasNext()) {Map.Entry mapentry = (Map.Entry) iterator.next(); /////Map.Entry－－Map的内部类，描述Map中的按键/数值对。  System.out.println(mapentry.getKey() + "   " + mapentry.getValue());}}}

//显示结果如下：//key3   val3//key2   val2//key1   val1