java HashMap的遍历步骤记录

java HashMap的遍历方法记录
java Map 遍历速度最优解

第一种:

Map map = new HashMap(); Iterator iter = map.entrySet().iterator(); while (iter.hasNext()) { Map.Entry entry = (Map.Entry) iter.next(); Object key = entry.getKey(); Object val = entry.getValue(); } 

Map map = new HashMap(); Iterator iter = map.keySet().iterator(); while (iter.hasNext()) { Object key = iter.next(); Object val = map.get(key); } 

Iterator<Entry<Integer, DMail>> iter=mlist.entrySet().iterator();while(iter.hasNext()){Entry<Integer, DMail> entry = iter.next();Integer key=entry.getKey();DMail val=entry.getValue();System.out.println(key.toString()+"==>"+val.toString());}