集合删除元素技巧 removeIf

        List<String> testList = new ArrayList<>();
        Iterator<String> it = testList.iterator();
        while (it.hasNext()) {
            if ("aa".equals(it.next())) {
                it.remove();
            }
        }

        testList.removeIf(s -> "aa".equals(s));
    // 或者
        testList.removeIf("aa"::equals);