Scala实现树形结构

 package graphx

 import java.util.ArrayList
 import java.util.List

 /**
   * Created by zhen on 2018/12/28.
   */
 object TreeParent {

   class Node {
     var id: String = ""
     var parent: Int = 0

     def this(id: String) {
       this()
       this.id = id
     }

     def this(id: String, parent: Int) {
       this()
       this.id = id
       this.parent = parent
     }

     override def toString: String = {
       return "TreeParent$Node [id=" + id + ", parent=" + parent + "]"
     }
   }
 }

 class TreeParent {
   private val list : List[TreeParent.Node] = new ArrayList[TreeParent.Node]()
   private var nodeNums: Int = 0

   /**
     * 指定根节点创建树
     */
   def this(id: String) {
     this()
     list.add(new TreeParent.Node(id, -1))
     nodeNums += 1
   }

   /**
     * 指定根节点、指定treeSize创建树
     */
   def this(id: String, treeSize: Int) {
     this()
     list.add(new TreeParent.Node(id, -1))
     nodeNums += 1
   }

   /**
     * 获取某个节点的索引值
     */
   def getNodeIndex(node: TreeParent.Node): Int = {
     for(i<- 0 until list.size())
     {
       if (list.get(i) eq node) {
         return i
       }
     }
     return -1
   }

   /**
     * 为指定节点添加子节点
     */
   def addNode(id: String, parent: TreeParent.Node) {
     list.add(new TreeParent.Node(id, getNodeIndex(parent)))
   }

   /**
     * 判断树是否为空
     */
   def isEmpty: Boolean = {
     return list.get(0) == null
   }

   /**
     * 返回根节点
     */
   def getRoot: TreeParent.Node = {
     return list.get(0)
   }

   /**
     * 返回指定节点(非根节点)的父节点
     */
   def getParent(node: TreeParent.Node): TreeParent.Node = {
     return list.get(node.parent)
   }

   def getNodeByid(id: String): TreeParent.Node = {
     for(i<- 0 until list.size())
     {
       if (list.get(i).id eq id) {
         return list.get(i)
       }
     }
     System.out.println("树中不存在包含该数据的节点")
     return null
   }

   /**
     * 返回指定节点(非叶子节点)的所有子节点
     */
   def getChildren(parent: TreeParent.Node): List[TreeParent.Node] = {
     val childrenList : List[TreeParent.Node] = new ArrayList[TreeParent.Node]()
     for(i <- 0 until list.size()){
       if (list.get(i) != null && list.get(i).parent == getNodeIndex(parent)) {
         childrenList.add(list.get(i))
       }
     }
     return childrenList
   }
 }

 object TreeAI {
   def main(args: Array[String]) {
     val tree: TreeParent = new TreeParent("root")
     val root: TreeParent.Node = tree.getRoot
     System.out.println(root)
     tree.addNode("A", root)
     tree.addNode("B", root)
     val A: TreeParent.Node = tree.getNodeByid("A")
     val B: TreeParent.Node = tree.getNodeByid("B")
     tree.addNode("C", A)
     tree.addNode("D", A)
     tree.addNode("E", B)
     tree.addNode("F", B)
     tree.addNode("G", B)
     tree.addNode("H", root)
     val H: TreeParent.Node = tree.getNodeByid("H")
     tree.addNode("I", H)
     val list: List[TreeParent.Node] = tree.getChildren(root)
     System.out.println("A节点的子节点为：")
     import scala.collection.JavaConversions._
     for (node <- list) {
       System.out.println(node)
     }
   }
 }

结果：