java list去除数据,Java中List集合去除重復數據的方法

1. 循環list中的所有元素然后刪除重復

public static List 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);

}

}

}

return list;

}

2. 通過HashSet踢除重復元素

public static List removeDuplicate(List list) {

HashSet h = new HashSet(list);

list.clear();

list.addAll(h);

return list;

}

3. 刪除ArrayList中重復元素，保持順序

// 刪除ArrayList中重復元素，保持順序

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);

}

4.把list里的對象遍歷一遍，用list.contain()，如果不存在就放入到另外一個list集合中

public static List removeDuplicate(List list){

List listTemp = new ArrayList();

for(int i=0;i

if(!listTemp.contains(list.get(i))){

listTemp.add(list.get(i));

}

}

return listTemp;

}