jsp删除ArrayList中重复元素的三种方法

// 删除ArrayList中重复元素
public static void removeDuplicate(List list) {
for ( int i = 0 ; i < list.size() - 1 ; i ++ ) {
   for ( int j = list.size() - 1 ; j > i; j -- ) {
       if (list.get(j).equals(list.get(i))) {
          list.remove(j); } } }
    System.out.println(list); }

// 删除ArrayList中重复元素
HashSet hSet = new HashSet(list);
list.clear();
list.addAll(hSet);
System.out.println(list);

// 删除ArrayList中重复元素，保持顺序 www.jb200.com
public static void removeDuplicateWithOrder(List list) {
Set set = new HashSet();
List newList = new ArrayList();
for (Iterator iter = list.iterator(); iter.hasNext();) {
   Object element = iter.next();
   if (set.add(element)) newList.add(element);
}

list.clear();
list.addAll(newList);
System.out.println( " remove duplicate " + list);
}