List通過HashSet去重

//JAVA中
//使用hashset去重復，set為重復的集合，可以通過new ArrayList(set)轉換成list
HashSet<HashMap<String, String>> set = new HashSet<>(); 
for(HashMap<String, String> student : list) { 
boolean add = set.add(student); 
  if (!add){ 
   //add=false 代表數據重復 
   } 
}

//簡單寫法
HashSet<HashMap<String, String>> set = new HashSet<HashMap<String, String>>(list);
List<HashMap<String, String>> List_1=new ArrayList<HashMap<String, String>>(set);