用map性能高些
private <T> List<T> getNewList(List<T> allList, List<T> existList) {
Map<T, Integer> map = new HashMap<>(16);
for (int i = 0; i < allList.size(); i++) {
map.put(allList.get(i), i);
}
for (int i = 0; i < existList.size(); i++) {
Integer pos = map.get(existList.get(i));
if (pos == null) {
continue;
}
allList.set(pos, null);
}
for (int i = allList.size() - 1; i >= 0; i--) {
if (allList.get(i) == null) {
allList.remove(i);
}
}
return allList;
}