遍历Map的几种方式

for (String key : map.keySet()) {

   System.out.println("key= "+ key + " and value= " + map.get(key));

  }

  

  //第二种

  Iterator<Map.Entry<String, String>> it = map.entrySet().iterator();

  while (it.hasNext()) {

   Map.Entry<String, String> entry = it.next();

   System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());

  }

  

  //第三种：推荐，尤其是容量大时

 

  for (Map.Entry<String, String> entry : map.entrySet()) {

   System.out.println("key= " + entry.getKey() + " and value= " + entry.getValue());

  }
  //第四种

 

  for (String v : map.values()) {

   System.out.println("value= " + v);

  }