java中map的集中遍历方式

• 样例
  Map<String,String> map = new HashMap<String,String>();
  map.put(“宝宝”, “儿童”);
  map.put(“妈妈”, “成人”);

• 1.最常用的遍历方式
  for(Map.Entry<String, String> entry : map.entrySet()){
  String mapKey = entry.getKey();
  String mapValue = entry.getValue();
  System.out.println(mapKey+":"+mapValue);
  }

• 2.单独遍历key或value

• //key
  for(String key : map.keySet()){
  System.out.println(key);
  }

• //value
  for(String value : map.values()){
  System.out.println(value);
  }

• 3.通过Iterator遍历
  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.不推荐
  for(String key : map.keySet()){
  String value = map.get(key);
  System.out.println(key+":"+value);
  }