遍历map的方法

方法一：通过map.entrySet(效率较高)

Map map = new HashMap();
  map.put("a", "1");
  map.put("b", "2");
  map.put("c", "3");
  map.put("d", "4");
  map.put("e", "5");
  for (Iterator iter = map.entrySet().iterator(); iter.hasNext();) {
      Map.Entry entry = (Map.Entry) iter.next();
      Object key = entry.getKey();
      Object val = entry.getValue();
      System.out.println("key:"+key);
      System.out.println("value:"+val);
  }

 

方法二：通过map.keySet(相当于二重循环，效率较低)

for (Iterator iter = map.keySet().iterator(); iter.hasNext();) {
      Object key = iter.next();
      Object val = map.get(key);
      System.out.println("key:"+key);
      System.out.println("value:"+val);
  }