嵌套树

第一步：新建treenode

@Data
@ApiModel(value = "树形节点")
public class TreeNode {
   @ApiModelProperty(value = "当前节点id")
   protected int id;
   @ApiModelProperty(value = "父节点id")
   protected int parentId;
   @ApiModelProperty(value = "子节点列表")
   protected List<TreeNode> children = new ArrayList<TreeNode>();

   public void add(TreeNode node) {
      children.add(node);
   }
}

第二步：查到所有的列  排序好

第三步：循环所有的列  再循环找每列的子集children set给这列（idpartenid）

/**
 * 使用递归方法建树
 *
 * @param treeNodes
 * @return
 */
public <T extends TreeNode> List<T> buildByRecursive(List<T> treeNodes, Object root) {
   List<T> trees = new ArrayList<T>();
   for (T treeNode : treeNodes) {
      if (root.equals(treeNode.getParentId())) {
         trees.add(findChildren(treeNode, treeNodes));
      }
   }
   return trees;
}

/**
 * 递归查找子节点
 *
 * @param treeNodes
 * @return
 */
public <T extends TreeNode> T findChildren(T treeNode, List<T> treeNodes) {
   for (T it : treeNodes) {
      if (treeNode.getId() == it.getParentId()) {
         if (treeNode.getChildren() == null) {
            treeNode.setChildren(new ArrayList<>());
         }
         treeNode.add(findChildren(it, treeNodes));
      }
   }
   return treeNode;
}

第三步