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Java list如何根据id获取子节点 Java list根据id获取子节点代码
时间:2020-03-21 编辑:袖梨 来源:一聚教程网
本篇文章小编给大家分享一下Java list根据id获取子节点代码,小编觉得挺不错的,现在分享给大家供大家参考,有需要的小伙伴们可以来看看。
实现思路
1.获取整个数据的list集合数据
2.将数据分组,java8 list有groupby分组,java8之前的自己遍历整理
3.分组后递归获取子节点,有子节点的添加,没有的设置子节点并删除分组的数据,知道分组数据删完
Tree.java
@Data public class Tree { private Integer id; private Integer pId; private String key; private String value; private ListchildList; }
TreeUtils.java
public class TreeUtils { static Listtrees ; static { String jsonStr = "[" + "{"id":100,"pId":1,"key":"root", "value": "root"}," + "{"id":1000,"pId":100,"key":"node1", "value": "node1"}," + "{"id":2000,"pId":100,"key":"node2","value": "node2"}," + "{"id":3000,"pId":100,"key":"node3","value": "node3"}," + "{"id":1100,"pId":1000,"key":"node11","value": "node11"}," + "{"id":1200,"pId":1000,"key":"node12","value": "node12"}," + "{"id":1110,"pId":1100,"key":"node111","value": "node111"}," + "{"id":1120,"pId":1100,"key":"node112","value": "node112"}," + "{"id":2100,"pId":2000,"key":"node21","value": "node21"}," + "{"id":2200,"pId":2000,"key":"node22","value": "node22"}," + "{"id":2110,"pId":2100,"key":"node211","value": "node21"}" + "]"; trees = JSONObject.parseArray(jsonStr, Tree.class); } public static void main(String[] args) { Tree tree = metaTree(trees, 100); /** * Tree@6073f712[id=100,pId=1,key=root,value=root,childList=[ * Tree(id=1000, pId=100, key=node1, value=node1, childList=[ * Tree(id=1100, pId=1000, key=node11, value=node11, childList=[ * Tree(id=1110, pId=1100, key=node111, value=node111, childList=null), * Tree(id=1120, pId=1100, key=node112, value=node112, childList=null)]), * Tree(id=1200, pId=1000, key=node12, value=node12, childList=null)]), * Tree(id=2000, pId=100, key=node2, value=node2, childList=[ * Tree(id=2100, pId=2000, key=node21, value=node21, childList=[ * Tree(id=2110, pId=2100, key=node211, value=node21, childList=null)]), * Tree(id=2200, pId=2000, key=node22, value=node22, childList=null)]), * Tree(id=3000, pId=100, key=node3, value=node3, childList=null)]] */ System.out.println("tree:" + ToStringBuilder.reflectionToString(tree)); } private static Tree metaTree(List treeList, Integer id) { //此处getId getPId根据自己实际情况更改 Tree treeConfig = treeList.stream().filter(tree -> tree.getId().equals(id)).collect(Collectors.toList()).get(0); Map > collect = treeList.stream().filter(type -> type.getPId() != null).collect(Collectors.groupingBy(Tree::getPId)); if (collect != null && collect.size() > 0) { recursion(collect, treeConfig); } return treeConfig; } private static Tree recursion(Map > maps, Tree tree) { if (tree.getChildList() == null) { if (maps.get(tree.getId()) != null) { tree.setChildList(maps.get(tree.getId())); maps.remove(tree.getId()); if (maps.size() > 0) { recursion(maps, tree); } } } else { List metaTypeList = tree.getChildList(); if (metaTypeList != null && metaTypeList.size() > 0) { for (Tree meta : metaTypeList) { recursion(maps, meta); } } } return tree; } }
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