Java层级List的排序怎么实现List<MyObject>

Question

MyObject:

long id;
long parentId;
long index;
List<MyObject> child;

顶级parentId = 0
.....如何根据index排序。。。。

现在好像是 默认的字典排序

Answer 1

Java排序，Java8方法外层排序直接list.sort(Comparator.comparing(t&nbsp;->&nbsp;((MyObject)&nbsp;t).getIndex()));外层排序好了过后再循环排序里面的list.forEach(t->{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;((MyObject)t).getChild().sort(Comparator.comparing(MyObject::getIndex)); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;});

Answer 2

&nbsp;private&nbsp;List<TextbookChapterTreeBO>&nbsp;children; &nbsp;&nbsp;&nbsp;&nbsp;public&nbsp;List<TextbookChapterTreeBO>&nbsp;getChildren()&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;children.forEach(t->{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;((TextbookChapterTreeBO)t).getChildren().sort(Comparator.comparing(TextbookChapterTreeBO::getIndex)); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}); &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;children; &nbsp;&nbsp;&nbsp;&nbsp;} &nbsp;&nbsp;&nbsp;&nbsp;public&nbsp;void&nbsp;setChildren(List<TextbookChapterTreeBO>&nbsp;children)&nbsp;{ &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;this.children&nbsp;=&nbsp;children; &nbsp;&nbsp;&nbsp;&nbsp;}把这个排序加到bean里就行了