摘要： 一.java集合类的比较：二、HashMap的遍历共有两种：1.利用entrySet 键值对映射：Map map = new HashMap();Iterator it = map.entrySet().iterator();while(it.hashNext()){ Map.Entry s = (Map.Entry)it.next(); System.out.println(s.getKey()); System.out.println(s.getValue());}2.利用keySet：Map map = new HashMap();Iterator it = map.keySet().i 阅读全文