HashMap 的两种遍历方式

	public static void main(String[] args) {
		Map<String, String> map = new HashMap<String, String>();
		map.put("a", "b");
		map.put("b", "b");
		for(Map.Entry<String, String> entry : map.entrySet()){
			System.out.println(entry.getKey() + entry.getValue());
		}
		
		Set<Map.Entry<String, String>> set = map.entrySet();
		Iterator<Map.Entry<String, String>> it = set.iterator();
		while(it.hasNext()){
			Map.Entry<String, String> item = it.next();
			System.out.println(item.getKey() + item.getValue());
		}
	}