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 getNewList(List li){
List list = new ArrayList();
for(int i=0; i arr = new ArrayList();
arr.add("aaa");
arr.add("bbb");
arr.add("aaa");
arr.add("ccc");
arr = getNewList(arr); //方法去重
System.out.println(arr);
}
}