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直接上码：
// 根据scId去重 ArrayList<Quota> collect = tickets.stream().collect( Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparingLong(Quota::getScId))), ArrayList::new));我写这段代码的时候自己先模拟出数据结构，重写了对象的equals和hashCode方法，但是不够简洁，参考stackoverflow上大神的，写出以上代码。
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回顾下stackoverflow的，参考资料
You can get a stream from the List and put in in the TreeSet from which you provide a custom comparator that compares id uniquely. Then if you really need a list you can put then back this collection into an ArrayList. 下面的代码就不复制过来了，具体根据参考资料了解。先看下
() -> new TreeSet<>(Comparator.comparingLong(Quota::getScId))这段代码/** * Constructs a new, empty tree set, sorted according to the specified * comparator. All elements inserted into the set must be <i>mutually * comparable</i> by the specified comparator: {@code comparator.compare(e1, * e2)} must not throw a {@code ClassCastException} for any elements * {@code e1} and {@code e2} in the set. If the user attempts to add * an element to the set that violates this constraint, the * {@code add} call will throw a {@code ClassCastException}. * * @param comparator the comparator that will be used to order this set. * If {@code null}, the {@linkplain Comparable natural * ordering} of the elements will be used. */ /** * 构造一个新的空树集，按照指定的比较器相互比较后放入。后面说的是比较规则不满足抛一个 * ClassCastException */ public TreeSet(Comparator<? super E> comparator) { this(new TreeMap<>(comparator)); }根据scId生成TreeSet,set又是key不重复的，所以我们达到根据属性去重的目的。
撒花★,°:.☆(￣▽￣)/$:.°★ 。
