java list去重

                  List<String> temps = new ArrayList<>();
                    for (OrderBalance item : itemVos) {
                            temps.add(item.getTradeNo());
                    }
                    HashSet<String> hs = new HashSet<String>(temps);
                    if (hs.size()<itemVos.size()) {
                        //存在重复元素
                    }

2:  去重
		Set<Tag> h = new LinkedHashSet<Tag>(tags);
		tags.clear();
		tags.addAll(h);