enhance TreeUtil.build

CHANGELOG.md

@@ -9,6 +9,7 @@
 * 【core   】     CharSequenceUtil增加join重载（issue#I3TFJ5@Gitee）
 * 【http   】     HttpRequest增加form方法重载（pr#337@Gitee）
 * 【http   】     ImgUtil增加getMainColor方法（pr#338@Gitee）
+* 【core   】     改进TreeUtil.buid算法性能（pr#1594@Github）
 
 ### 🐞Bug修复
 * 【core   】     修复FileUtil.normalize去掉末尾空格问题（issue#1603@Github）

hutool-core/src/main/java/cn/hutool/core/lang/tree/Tree.java

@@ -1,8 +1,15 @@
 package cn.hutool.core.lang.tree;
 
+import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.lang.Assert;
+import cn.hutool.core.util.ArrayUtil;
+import cn.hutool.core.util.CharUtil;
 import cn.hutool.core.util.ObjectUtil;
+import cn.hutool.core.util.StrUtil;
 
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 
@@ -152,8 +159,32 @@ public class Tree<T> extends LinkedHashMap<String, Object> implements Node<T> {
 		return (List<Tree<T>>) this.get(treeNodeConfig.getChildrenKey());
 	}
 
-	public void setChildren(List<Tree<T>> children) {
+	public Tree<T> setChildren(List<Tree<T>> children) {
 		this.put(treeNodeConfig.getChildrenKey(), children);
+		return this;
+	}
+
+	/**
+	 * 增加子节点，同时关联子节点的父节点为当前节点
+	 *
+	 * @param children 子节点列表
+	 * @return this
+	 * @since 5.6.7
+	 */
+	@SafeVarargs
+	public final Tree<T> addChildren(Tree<T>... children){
+		if(ArrayUtil.isNotEmpty(children)){
+			List<Tree<T>> childrenList = this.getChildren();
+			if(null == childrenList){
+				childrenList = new ArrayList<>();
+				setChildren(childrenList);
+			}
+			for (Tree<T> child : children) {
+				child.setParent(this);
+				childrenList.add(child);
+			}
+		}
+		return this;
 	}
 
 	/**
@@ -166,4 +197,29 @@ public class Tree<T> extends LinkedHashMap<String, Object> implements Node<T> {
 		Assert.notEmpty(key, "Key must be not empty !");
 		this.put(key, value);
 	}
-}
+
+	@Override
+	public String toString() {
+		final StringWriter stringWriter = new StringWriter();
+		printTree(this, new PrintWriter(stringWriter), 0);
+		return stringWriter.toString();
+	}
+
+	/**
+	 * 打印
+	 * @param tree 树
+	 * @param writer Writer
+	 * @param intent 缩进量
+	 */
+	private static void printTree(Tree<?> tree, PrintWriter writer, int intent){
+		writer.println(StrUtil.format("{}{}[{}]", StrUtil.repeat(CharUtil.SPACE, intent), tree.getName(), tree.getId()));
+		writer.flush();
+
+		final List<? extends Tree<?>> children = tree.getChildren();
+		if(CollUtil.isNotEmpty(children)){
+			for (Tree<?> child : children) {
+				printTree(child, writer, intent + 2);
+			}
+		}
+	}
+}

hutool-core/src/main/java/cn/hutool/core/lang/tree/TreeUtil.java

@@ -3,11 +3,13 @@ package cn.hutool.core.lang.tree;
 import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.lang.tree.parser.DefaultNodeParser;
 import cn.hutool.core.lang.tree.parser.NodeParser;
+import cn.hutool.core.map.MapUtil;
 import cn.hutool.core.util.ObjectUtil;
 
 import java.util.ArrayList;
+import java.util.LinkedHashMap;
 import java.util.List;
-import java.util.stream.Collectors;
+import java.util.Map;
 
 /**
  * 树工具类
@@ -58,65 +60,49 @@ public class TreeUtil {
 	 * @param <T>            转换的实体 为数据源里的对象类型
 	 * @param <E>            ID类型
 	 * @param list           源数据集合
-	 * @param parentId       最顶层父id值 一般为 0 之类
+	 * @param rootId       最顶层父id值 一般为 0 之类
 	 * @param treeNodeConfig 配置
 	 * @param nodeParser     转换器
 	 * @return List
 	 */
-	public static <T, E> List<Tree<E>> build(List<T> list, E parentId, TreeNodeConfig treeNodeConfig, NodeParser<T, E> nodeParser) {
+	public static <T, E> List<Tree<E>> build(List<T> list, E rootId, TreeNodeConfig treeNodeConfig, NodeParser<T, E> nodeParser) {
-		final List<Tree<E>> treeList = CollUtil.newArrayList();
+		final Map<E, Tree<E>> map = new LinkedHashMap<>(list.size(), 1);
-		Tree<E> tree;
+		Tree<E> node;
-		for (T obj : list) {
+		for (T t : list) {
-			tree = new Tree<>(treeNodeConfig);
+			node = new Tree<>(treeNodeConfig);
-			nodeParser.parse(obj, tree);
+			nodeParser.parse(t, node);
-			treeList.add(tree);
+			map.put(node.getId(), node);
 		}
 
-		List<Tree<E>> finalTreeList = CollUtil.newArrayList();
+		return build(map, rootId);
-		for (Tree<E> node : treeList) {
-			if (ObjectUtil.equals(parentId,node.getParentId())) {
-				finalTreeList.add(node);
-				innerBuild(treeList, node, 0, treeNodeConfig.getDeep());
-			}
-		}
-		// 内存每层已经排过了 这是最外层排序
-		finalTreeList = finalTreeList.stream().sorted().collect(Collectors.toList());
-		return finalTreeList;
 	}
 
 	/**
-	 * 递归处理
+	 * 树构建，按照权重排序
 	 *
-	 * @param treeNodes  数据集合
+	 * @param <E>            ID类型
-	 * @param parentNode 当前节点
+	 * @param map           源数据Map
-	 * @param deep       已递归深度
+	 * @param rootId       最顶层父id值 一般为 0 之类
-	 * @param maxDeep    最大递归深度 可能为null即不限制
+	 * @return List
+	 * @since 5.6.7
 	 */
-	private static <T> void innerBuild(List<Tree<T>> treeNodes, Tree<T> parentNode, int deep, Integer maxDeep) {
+	public static <E> List<Tree<E>> build(Map<E, Tree<E>> map, E rootId) {
+		final Map<E, Tree<E>> eTreeMap = MapUtil.sortByValue(map, false);
+		List<Tree<E>> rootTreeList = CollUtil.newArrayList();
+		E parentId;
+		for (Tree<E> node : eTreeMap.values()) {
+			parentId = node.getParentId();
+			if(ObjectUtil.equals(rootId, parentId)){
+				rootTreeList.add(node);
+				continue;
+			}
 
-		if (CollUtil.isEmpty(treeNodes)) {
+			final Tree<E> parentNode = map.get(parentId);
-			return;
+			if(null != parentNode){
-		}
+				parentNode.addChildren(node);
-		//maxDeep 可能为空
-		if (maxDeep != null && deep >= maxDeep) {
-			return;
-		}
-
-		// 每层排序 TreeNodeMap 实现了Comparable接口
-		treeNodes = treeNodes.stream().sorted().collect(Collectors.toList());
-		for (Tree<T> childNode : treeNodes) {
-			if (parentNode.getId().equals(childNode.getParentId())) {
-				List<Tree<T>> children = parentNode.getChildren();
-				if (children == null) {
-					children = CollUtil.newArrayList();
-					parentNode.setChildren(children);
-				}
-				children.add(childNode);
-//				childNode.setParentId(parentNode.getId());
-				childNode.setParent(parentNode);
-				innerBuild(treeNodes, childNode, deep + 1, maxDeep);
 			}
 		}
+		return rootTreeList;
 	}
 
 	/**
@@ -138,7 +124,7 @@ public class TreeUtil {
 		if(null == children) {
 			return null;
 		}
-		
+
 		// 查找子节点
 		Tree<T> childNode;
 		for (Tree<T> child : children) {
@@ -182,5 +168,4 @@ public class TreeUtil {
 		}
 		return result;
 	}
-
 }

hutool-core/src/test/java/cn/hutool/core/lang/tree/TreeTest.java

@@ -18,8 +18,8 @@ public class TreeTest {
 	static {
 		// 模拟数据
 		nodeList.add(new TreeNode<>("1", "0", "系统管理", 5));
-		nodeList.add(new TreeNode<>("11", "1", "用户管理", 222222));
 		nodeList.add(new TreeNode<>("111", "11", "用户添加", 0));
+		nodeList.add(new TreeNode<>("11", "1", "用户管理", 222222));
 
 		nodeList.add(new TreeNode<>("2", "0", "店铺管理", 1));
 		nodeList.add(new TreeNode<>("21", "2", "商品管理", 44));
@@ -33,6 +33,7 @@ public class TreeTest {
 		for (Tree<String> tree : treeList) {
 			Assert.assertNotNull(tree);
 			Assert.assertEquals("0", tree.getParentId());
+//			Console.log(tree);
 		}
 
 		// 测试通过子节点查找父节点