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); }

public static void removeDuplicate(List list) { HashSet h = new HashSet(list); list.clear(); list.addAll(h); System.out.println(list); } 

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); } 

publi List<String> getNewList(List<String> li){List<String> list = new ArrayList<String>();for(int i=0; i<li.size(); i++){String str = li.get(i); //獲取傳入集合對象的每一個元素if(!list.contains(str)){ //查看新集合中是否有指定的元素，如果沒有則加入list.add(str);}}return list; //返回集合}public class Test{public static void main(String[] args){ArrayList<String> arr = new ArrayList<String>();arr.add("aaa");arr.add("bbb");arr.add("aaa");arr.add("ccc");arr = getNewList(arr); //方法去重System.out.println(arr);}}