java中map的集中周遊方式

• 樣例

  Map<String,String> map = new HashMap<String,String>();

  map.put(“寶寶”, “兒童”);

  map.put(“媽媽”, “成人”);

• 1.最常用的周遊方式

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

  String mapKey = entry.getKey();

  String mapValue = entry.getValue();

  System.out.println(mapKey+":"+mapValue);

  }

• 2.單獨周遊key或value

• //key

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

  System.out.println(key);

  }

• //value

  for(String value : map.values()){

  System.out.println(value);

  }

• 3.通過Iterator周遊

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

  while(entries.hasNext()){

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

  String key = entry.getKey();

  String value = entry.getValue();

  System.out.println(key+":"+value);

  }

• 4.不推薦

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

  String value = map.get(key);

  System.out.println(key+":"+value);

  }