list删除重复数据

方法一：循环元素删除

// 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); 

}

方法二：通过HashSet剔除

// 删除ArrayList中重复元素 

public static void removeDuplicate(List list) { 

 HashSet h = new HashSet(list); 

 list.clear(); 

 list.addAll(h); 

 System.out.println(list); 

}

方法三： 删除ArrayList中重复元素，保持顺序

// 删除ArrayList中重复元素，保持顺序 

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); 

}