列表与重复项没有重复

Question

I have a list with duplicate values.

List<valFile> isList = valBo.findId();

isList has values like {100, 100, 100, 102, 105, 105}

I want to remove these duplicates and use the same list with no duplicates. I tried set but dont know how to use the same list without duplicates.

Answer 1

Create a LinkedHashSet to maintain the ordering and add all the items from the List. The duplicates will be discarded:

Set<valFile> set = new LinkedHashSet<valFile>(isList);

Then add it back to a list:

List<valFile> listWithoutDuplicates = new ArrayList<valFile>(set);

Answer 2

I would use a set and dump back to a list.

List<valFile> unique = new ArrayList<valFile>(new HashSet<valFile>(islist));
Collections.sort(unique);

Or if you have a good comparator, you can use a TreeSet

Set<valFile> unique = new TreeSet<valFile>(isList);

If you absolutely MUST use the same list (perhaps because there are other references to it somewhere), your best bet is to clear it.

List<valFile> unique = new ArrayList<valFile>(new HashSet<valFile>(islist));
Collections.sort(unique);
isList.clear();
isList.addAll(unique);