建立一個(gè)二叉樹(shù)，附帶查詢代碼，JAVA代碼

import java.util.ArrayList;

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// 樹(shù)的一個(gè)節(jié)點(diǎn)

class TreeNode {

Object _value = null; // 他的值

TreeNode _parent = null; // 他的父節(jié)點(diǎn)，根節(jié)點(diǎn)沒(méi)有PARENT

ArrayList _childList = new ArrayList(); // 他的孩子節(jié)點(diǎn)

public TreeNode( Object value, TreeNode parent ){

this._parent = parent;

this._value = value;

}

public TreeNode getParent(){

return _parent;

}

public String toString() {

return _value.toString();

}

}

public class Tree {

// 給出寬度優(yōu)先遍歷的值數(shù)組，構(gòu)建出一棵多叉樹(shù)

// null 值表示一個(gè)層次的結(jié)束

// "|" 表示一個(gè)層次中一個(gè)父親節(jié)點(diǎn)的孩子輸入結(jié)束

// 如：給定下面的值數(shù)組：

// { "root", null, "left", "right", null }

// 則構(gòu)建出一個(gè)根節(jié)點(diǎn)，帶有兩個(gè)孩子("left","right")的樹(shù)

public Tree( Object[] values ){

// 創(chuàng)建根

_root = new TreeNode( values[0], null );

// 創(chuàng)建下面的子節(jié)點(diǎn)

TreeNode currentParent = _root; // 用于待創(chuàng)建節(jié)點(diǎn)的父親

//TreeNode nextParent = null;

int currentChildIndex = 0; // 表示 currentParent 是他的父親的第幾個(gè)兒子

//TreeNode lastNode = null; // 最后一個(gè)創(chuàng)建出來(lái)的TreeNode，用于找到他的父親

for ( int i = 2; i values.length; i++ ){

// 如果null ,表示下一個(gè)節(jié)點(diǎn)的父親是當(dāng)前節(jié)點(diǎn)的父親的第一個(gè)孩子節(jié)點(diǎn)

if ( values[i] == null ){

currentParent = (TreeNode)currentParent._childList.get(0);

currentChildIndex = 0;

continue;

}

// 表示一個(gè)父節(jié)點(diǎn)的所有孩子輸入完畢

if ( values[i].equals("|") ){

if ( currentChildIndex+1 currentParent._childList.size() ){

currentChildIndex++;

currentParent = (TreeNode)currentParent._parent._childList.get(currentChildIndex);

}

continue;

}

TreeNode child = createChildNode( currentParent, values[i] );

}

}

TreeNode _root = null;

public TreeNode getRoot(){

return _root;

}

/**

// 按寬度優(yōu)先遍歷，打印出parent子樹(shù)所有的節(jié)點(diǎn)

private void printSteps( TreeNode parent, int currentDepth ){

for ( int i = 0; i parent._childList.size(); i++ ){

TreeNode child = (TreeNode)parent._childList.get(i);

System.out.println(currentDepth+":"+child);

}

if ( parent._childList.size() != 0 ) System.out.println(""+null);// 為了避免葉子節(jié)點(diǎn)也會(huì)打印null

//打印 parent 同層的節(jié)點(diǎn)的孩子

if ( parent._parent != null ){ // 不是root

int i = 1;

while ( i parent._parent._childList.size() ){// parent 的父親還有孩子

TreeNode current = (TreeNode)parent._parent._childList.get(i);

printSteps( current, currentDepth );

i++;

}

}

// 遞歸調(diào)用，打印所有節(jié)點(diǎn)

for ( int i = 0; i parent._childList.size(); i++ ){

TreeNode child = (TreeNode)parent._childList.get(i);

printSteps( child, currentDepth+1 );

}

}

// 按寬度優(yōu)先遍歷，打印出parent子樹(shù)所有的節(jié)點(diǎn)

public void printSteps(){

System.out.println(""+_root);

System.out.println(""+null);

printSteps(_root, 1 );

}**/

// 將給定的值做為 parent 的孩子，構(gòu)建節(jié)點(diǎn)

private TreeNode createChildNode( TreeNode parent, Object value ){

TreeNode child = new TreeNode( value , parent );

parent._childList.add( child );

return child;

}

public static void main(String[] args) {

Tree tree = new Tree( new Object[]{ "root", null,

"left", "right", null,

"l1","l2","l3", "|", "r1","r2",null } );

//tree.printSteps();

System.out.println(""+ ( (TreeNode)tree.getRoot()._childList.get(0) )._childList.get(0) );

System.out.println(""+ ( (TreeNode)tree.getRoot()._childList.get(0) )._childList.get(1) );

System.out.println(""+ ( (TreeNode)tree.getRoot()._childList.get(0) )._childList.get(2) );

System.out.println(""+ ( (TreeNode)tree.getRoot()._childList.get(1) )._childList.get(0) );

System.out.println(""+ ( (TreeNode)tree.getRoot()._childList.get(1) )._childList.get(1) );

}

}

java：二叉樹(shù)添加和查詢方法

package arrays.myArray;

public class BinaryTree {

private Node root;

// 添加數(shù)據(jù)

public void add(int data) {

// 遞歸調(diào)用

if (null == root)

root = new Node(data, null, null);

else

addTree(root, data);

}

private void addTree(Node rootNode, int data) {

// 添加到左邊

if (rootNode.data data) {

if (rootNode.left == null)

rootNode.left = new Node(data, null, null);

else

addTree(rootNode.left, data);

} else {

// 添加到右邊

if (rootNode.right == null)

rootNode.right = new Node(data, null, null);

else

addTree(rootNode.right, data);

}

}

// 查詢數(shù)據(jù)

public void show() {

showTree(root);

}

private void showTree(Node node) {

if (node.left != null) {

showTree(node.left);

}

System.out.println(node.data);

if (node.right != null) {

showTree(node.right);

}

}

}

class Node {

int data;

Node left;

Node right;

public Node(int data, Node left, Node right) {

this.data = data;

this.left = left;

this.right = right;

}

}

JAVA數(shù)據(jù)結(jié)構(gòu)關(guān)于查找樹(shù)的節(jié)點(diǎn)的代碼分析

你好，遞歸調(diào)用簡(jiǎn)單的說(shuō)就是自己無(wú)限的調(diào)用自己的下一級(jí)，也就是說(shuō)父節(jié)點(diǎn)和子節(jié)點(diǎn)擁有相同的屬性和方法，所以在處理玩當(dāng)前節(jié)點(diǎn)也就是父節(jié)點(diǎn)的時(shí)候，就調(diào)用處理自身下面的子節(jié)點(diǎn)，類似于文件夾和文件，文件夾相對(duì)于當(dāng)前目錄來(lái)說(shuō)是父節(jié)點(diǎn)，而他里面的子文件夾就相當(dāng)于子節(jié)點(diǎn)，但是處理子文件夾的時(shí)候，子文件夾就成了父節(jié)點(diǎn)，一次遞歸處理完畢

希望可以幫助到你

java 動(dòng)態(tài)的給樹(shù)添加新節(jié)點(diǎn) 望高手指點(diǎn)啊

//先選中節(jié)點(diǎn)才能增加節(jié)點(diǎn)

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;

import javax.swing.event.*;

import javax.swing.tree.*;

public class TreeTest implements ActionListener,TreeModelListener{

JLabel label=null;

JTree tree=null;

DefaultTreeModel treeModel=null;

String nodeName=null;//原有節(jié)點(diǎn)名稱

public TreeTest(){

JFrame f=new JFrame("TreeTest");

Container contentPane=f.getContentPane();

DefaultMutableTreeNode root=new DefaultMutableTreeNode("資源管理器");

tree=new JTree(root);

tree.setEditable(true);

tree.addMouseListener(new MouseHandle());

treeModel=(DefaultTreeModel)tree.getModel();

treeModel.addTreeModelListener(this);

JScrollPane scrollPane=new JScrollPane();

scrollPane.setViewportView(tree);

JPanel panel=new JPanel();

JButton b=new JButton("新增節(jié)點(diǎn)");

b.addActionListener(this);

panel.add(b);

b=new JButton("刪除節(jié)點(diǎn)");

b.addActionListener(this);

panel.add(b);

b=new JButton("清除所有節(jié)點(diǎn)");

b.addActionListener(this);

panel.add(b);

label=new JLabel("Action");

contentPane.add(panel,BorderLayout.NORTH);

contentPane.add(scrollPane,BorderLayout.CENTER);

contentPane.add(label,BorderLayout.SOUTH);

f.pack();

f.setVisible(true);

f.addWindowListener(new WindowAdapter(){

public void windowClosing(WindowEvent e){

System.exit(0);

}

});

}

//本方法運(yùn)行新增、刪除、清除所有節(jié)點(diǎn)的程序代碼.

public void actionPerformed(ActionEvent ae){

if (ae.getActionCommand().equals("新增節(jié)點(diǎn)")){

DefaultMutableTreeNode parentNode=null;

DefaultMutableTreeNode newNode=new DefaultMutableTreeNode("新節(jié)點(diǎn)");

newNode.setAllowsChildren(true);

TreePath parentPath=tree.getSelectionPath();

//取得新節(jié)點(diǎn)的父節(jié)點(diǎn)

parentNode=(DefaultMutableTreeNode)(parentPath.getLastPathComponent());

//由DefaultTreeModel的insertNodeInto（）方法增加新節(jié)點(diǎn)

treeModel.insertNodeInto(newNode,parentNode,parentNode.getChildCount());

//tree的scrollPathToVisible()方法在使Tree會(huì)自動(dòng)展開(kāi)文件夾以便顯示所加入的新節(jié)點(diǎn)。若沒(méi)加這行則加入的新節(jié)點(diǎn)

//會(huì)被 包在文件夾中，你必須自行展開(kāi)文件夾才看得到。

tree.scrollPathToVisible(new TreePath(newNode.getPath()));

label.setText("新增節(jié)點(diǎn)成功");

}

if (ae.getActionCommand().equals("刪除節(jié)點(diǎn)")){

TreePath treepath=tree.getSelectionPath();

if (treepath!=null){

//下面兩行取得選取節(jié)點(diǎn)的父節(jié)點(diǎn).

DefaultMutableTreeNode selectionNode=(DefaultMutableTreeNode)treepath.getLastPathComponent();

TreeNode parent=(TreeNode)selectionNode.getParent();

if (parent!=null) {

//由DefaultTreeModel的removeNodeFromParent()方法刪除節(jié)點(diǎn)，包含它的子節(jié)點(diǎn)。

treeModel.removeNodeFromParent(selectionNode);

label.setText("刪除節(jié)點(diǎn)成功");

}

}

}

if (ae.getActionCommand().equals("清除所有節(jié)點(diǎn)")){

//下面一行，由DefaultTreeModel的getRoot()方法取得根節(jié)點(diǎn).

DefaultMutableTreeNode rootNode=(DefaultMutableTreeNode)treeModel.getRoot();

//下面一行刪除所有子節(jié)點(diǎn).

rootNode.removeAllChildren();

//刪除完后務(wù)必運(yùn)行DefaultTreeModel的reload()操作，整個(gè)Tree的節(jié)點(diǎn)才會(huì)真正被刪除.

treeModel.reload();

label.setText("清除所有節(jié)點(diǎn)成功");

}

}

public void treeNodesChanged(TreeModelEvent e){

TreePath treePath=e.getTreePath();

DefaultMutableTreeNode node=(DefaultMutableTreeNode)treePath.getLastPathComponent();

try{

int[] index=e.getChildIndices();

node=(DefaultMutableTreeNode)node.getChildAt(index[0]);

}catch(NullPointerException exc){}

label.setText(nodeName+"更改數(shù)據(jù)為:"+(String)node.getUserObject());

}

public void treeNodesInserted(TreeModelEvent e){

System.out.println("new node insered");

}

public void treeNodesRemoved(TreeModelEvent e){

System.out.println("node deleted");

}

public void treeStructureChanged(TreeModelEvent e){

System.out.println("Structrue changed");

}

public static void main(String[] args){

new TreeTest();

}

class MouseHandle extends MouseAdapter{

public void mousePressed(MouseEvent e){

try{

JTree tree=(JTree)e.getSource();

int rowLocation=tree.getRowForLocation(e.getX(),e.getY());

TreePath treepath=tree.getPathForRow(rowLocation);

TreeNode treenode=(TreeNode)treepath.getLastPathComponent();

nodeName=treenode.toString();

}catch(NullPointerException ne){}

}

}

}

java 求二叉樹(shù)的葉子結(jié)點(diǎn)，下面的代碼不知道哪里出錯(cuò)了！

我看了一下，知道lz的錯(cuò)誤在哪了。

createbintree方法中。以lz的講的先輸入a、再輸入三回車，也就是當(dāng)前只有一個(gè)節(jié)點(diǎn)a。下面就以樓主的數(shù)據(jù)來(lái)講一下函數(shù)所走流程

1.可是當(dāng)樓主輸入a之后，按完第一個(gè)回車

當(dāng)前取得的數(shù)據(jù)a，走else分支，接下來(lái)就到myTree.data = str;//為節(jié)點(diǎn)賦值，假設(shè)為父節(jié)點(diǎn)1

myTree.lchild = new BintNode();//為myTree建立了左節(jié)點(diǎn)

createbintree(myTree.lchild);

//遞歸調(diào)用跳到2

myTree.rchild = new BintNode();//創(chuàng)建右節(jié)點(diǎn)

createbintree(myTree.rchild);

//遞歸調(diào)用跳到3

2.輸入第二個(gè)回車，數(shù)據(jù)為空，那么走if分支，myTree=null，照理說(shuō)應(yīng)該將myTree該節(jié)點(diǎn)賦值為空，也就代表沒(méi)有該節(jié)點(diǎn)。

其實(shí)這個(gè)想法是錯(cuò)誤的。在1中，為父節(jié)點(diǎn)1分配了左孩子，已經(jīng)是new出來(lái)的對(duì)象。不知道lz對(duì)函數(shù)調(diào)用中的形參(也就是函數(shù)名所帶的參數(shù))的值，是怎么理解。有兩種形式的

1)值傳遞：即使是值傳遞，在函數(shù)體中，改變的也只是一個(gè)臨時(shí)變量的值。并不會(huì)影響到實(shí)參的值

2)引用傳遞：對(duì)象間的傳遞，而這傳遞只是引用關(guān)系的傳遞。就是將該參數(shù)指向該類，如果在函數(shù)體中設(shè)為null，也只是將形參與實(shí)際對(duì)象間的引用關(guān)系給去掉

本程序中，是屬于引用傳遞，在createbintree將myTree=null，也只是斷掉myTree與外部對(duì)象的關(guān)系而已，即父節(jié)點(diǎn)1的左孩子間的關(guān)系，所以父節(jié)點(diǎn)1的左孩子不為null

3.與2同樣的解釋，也可知道右孩子也不為空。

那么在調(diào)用num來(lái)計(jì)算葉子的個(gè)數(shù)時(shí)候，是不是根結(jié)點(diǎn)一開(kāi)始進(jìn)來(lái)，左右孩子都不為null，所以自然最后一個(gè)else。那么往下，lz再計(jì)算一下就知道結(jié)果為2

建議修改的話：

在createbintree方法中，if ("".equals(str.trim()))為空時(shí)，則myTree.data=null

然后在num方法中，計(jì)算個(gè)數(shù)的話，利用myTree.data==null return 0 ; myTree.lchild.data==null myTree.rchild.data==null return 1 ; else 一樣

JAVA中如何刪除樹(shù)中所選的節(jié)點(diǎn)？

//獲得商品分類樹(shù)形結(jié)構(gòu)

private JTree getTree(){

if(tree ==null)

{

tree = new JTree(getTreeModel());

tree.setBorder(new EtchedBorder(EtchedBorder.LOWERED));

// tree = new JTable(getModel());

tree.getSelectionModel().setSelectionMode(

TreeSelectionModel.SINGLE_TREE_SELECTION);

// 節(jié)點(diǎn)選擇事件

tree.addTreeSelectionListener(new TreeSelectionListener() {

public void valueChanged(TreeSelectionEvent e) {

treeSelection();

}

});

tree.addMouseListener(new MouseAdapter(){

public void mousePressed(MouseEvent e){

if(e.getButton()==MouseEvent.BUTTON3)

{

int selRow = tree.getRowForLocation(e.getX(), e.getY());

tree.setSelectionRow(selRow);

TreePath selPath = tree.getPathForLocation(e.getX(), e.getY());

if(selRow != -1) {

if(e.getClickCount() == 1) {

// myRightClick(selRow, selPath);

selectedNode = (DefaultMutableTreeNode) selPath.getLastPathComponent();

showPopMenu(selRow,selPath,e.getX(),e.getY());

}

}

}

}

});

}

return tree;

}

/**

* 獲得當(dāng)前選擇的商品對(duì)象

* @return

*

*/

private Goods getSelectedGoods(){

int row = table.getSelectedRow();

if(row!=-1)

{

String code = (String)getModel().getValueAt(row,0);

Goods g= gHandle.getGoodsByCode(code);

return g;

}

return null;

}

/**

* 樹(shù)形結(jié)構(gòu)上顯示右鍵菜單

* @param selRow

* @param selPath

*

*/

private void showPopMenu(int selRow, TreePath path,int x,int y) {

// tree.add(getPopMenu());

if (path == null)

return;

//點(diǎn)的是根結(jié)點(diǎn)

if(selectedNode.isRoot())

{

JPopupMenu pop = getPopMenu(1,path,selRow);

// System.out.println(selRow);

this.getContentPane().add(pop);

pop.show(tree,x,y);

}

//葉結(jié)點(diǎn)

if(selectedNode.isLeaf())

{

JPopupMenu pop = getPopMenu(0,path,selRow);

this.getContentPane().add(pop);

pop.show(tree,x,y);

}

}

/**

* 創(chuàng)建右鍵菜單

* @param action

* @return

*

*/

private JPopupMenu getPopMenu(int action,final TreePath path,final int selRow){

if(pop==null)

{

pop = new JPopupMenu();

//新建類別事件處理

addItem.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e) {

String value = JOptionPane.showInputDialog("請(qǐng)輸入新類別的名稱:");

if(value==null||value.trim().length()==0)

return;

GoodsCategoryHandle gcHandle = new GoodsCategoryHandle();

if(gcHandle.isExsited(value))

{

JOptionPane.showMessageDialog(null, "該類別名稱已經(jīng)存在!", "提示", JOptionPane.ERROR_MESSAGE);

return ;

}

DefaultMutableTreeNode newNode =new DefaultMutableTreeNode(value);

treeModel.insertNodeInto(newNode,(MutableTreeNode)treeModel.getRoot(),selRow-1);

GoodsCategory gc = new GoodsCategory();

gc.setCategoryName(value);

//更新到數(shù)據(jù)庫(kù)中

gcHandle.addCategory(gc);

}

});

//重命名類別名稱事件處理

renameItem.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e) {

String value = JOptionPane.showInputDialog(null,"請(qǐng)輸入新類別的名稱:",selectedNode.toString());

if(value==null||value.trim().length()==0)

return;

GoodsCategoryHandle gcHandle = new GoodsCategoryHandle();

if(gcHandle.isExsited(value))

{

JOptionPane.showMessageDialog(null, "該類別名稱已經(jīng)存在!", "提示", JOptionPane.ERROR_MESSAGE);

return ;

}

GoodsCategory gc =gcHandle.getCategory(selectedNode.toString());

gc.setCategoryName(value);

//更新到數(shù)據(jù)庫(kù)中

gcHandle.modifyCategory(gc);

selectedNode.setUserObject(value);

tree.setModel(getTreeModel());

}

});

//移除結(jié)點(diǎn)事件處理

delItem.addActionListener(new ActionListener(){

public void actionPerformed(ActionEvent e) {

int i =JOptionPane.showConfirmDialog(null,

"慎重!刪除類別后,該類別下的所有商品將全部被刪除,確認(rèn)后繼續(xù)", "提示", JOptionPane.YES_NO_OPTION);

if(i==JOptionPane.YES_OPTION)

{

GoodsCategoryHandle gcHandle = new GoodsCategoryHandle();

GoodsHandle gHandle = new GoodsHandle();

int id = (gcHandle.getCategory(selectedNode.toString().trim())).getCategoryId();

ArrayList al = gHandle.getGoodsByCategory(id);

boolean b_bak = false;

//對(duì)刪除商品的備分

try {

FileWriter out = new FileWriter("/"+CommonUtil.getTime()+"商品刪除bak.db",true);

out.write("商品名稱"+" "+"商品分類"+" "+

"商品別名"+" "+"商品單位"+" "+

"商品廠商"+" "+"商品庫(kù)存上限"+" "+

"商品庫(kù)存下限"+" "+

"商品庫(kù)存下限"+" "+

"商品參考售價(jià)"+" "+

"商品實(shí)際庫(kù)存");

out.write('\n');

for(int j=0;jal.size();j++)

{

Goods g = (Goods)al.get(j);

out.write(g.toString());

out.write('\n');

}

out.close();

b_bak=true;

} catch (IOException e1) {

e1.printStackTrace();

b_bak = false;

}

gcHandle.setCommit(false);

boolean g_del=gHandle.deleteByCategoryId(id);

boolean gc_del=gcHandle.deleteById(id);

//只有類別刪除成功，該類別下的商品刪除成功，并且備分成功后才提交刪除

if(g_delgc_delb_bak)

gcHandle.commit();

else

{

// System.out.println("fail");

gcHandle.rollBack();

JOptionPane.showMessageDialog(null, "刪除失敗，可能是因?yàn)樵擃悇e下的商品存在銷售記錄，不能被刪除！", "提示", JOptionPane.ERROR_MESSAGE);

}

tree.setModel(getTreeModel());

tree.setSelectionRow(0);

}

else

return;

}

});

pop.add(addItem);

pop.add(delItem);

pop.add(renameItem);

}

if(action ==1)

{

delItem.setEnabled(false);

renameItem.setEnabled(false);

}

if(action ==0)

{

delItem.setEnabled(true);

renameItem.setEnabled(true);

}

return pop;

}

/**

* 用戶在商品分類樹(shù)上的事件處理

*

*

*/

private void treeSelection(){

TreePath path = tree.getSelectionPath();

if (path == null)

return;

DefaultMutableTreeNode node = (DefaultMutableTreeNode) path

.getLastPathComponent();

selectedCategory = cHandle.getCategory(node.toString());

// 若選中的是根節(jié)點(diǎn)

if (node.isRoot())

showAllGoods();

if(node.isLeaf()){

model.setRowCount(0);

ArrayList al = gHandle.getGoodsByCategoryName(node

.toString());

for (int i = 0; i al.size(); i++) {

Goods g = (Goods) al.get(i);

model.addRow(getRow(g));

}

}

}

public GoodsCategory getCategory(){

return this.selectedCategory;

}

/**

* 生產(chǎn)樹(shù)形列表的數(shù)據(jù)模型

*

* @return

*

*/

private TreeModel getTreeModel() {

DefaultMutableTreeNode root = new DefaultMutableTreeNode(

PropertiesUtil.getString("categoryTree.all"));

ArrayList categoryList = cHandle.getAllCategory();

// 添加子節(jié)點(diǎn)

for (int i = 0; i categoryList.size(); i++) {

GoodsCategory gc = (GoodsCategory) categoryList.get(i);

String name = gc.getCategoryName();

DefaultMutableTreeNode node = new DefaultMutableTreeNode(name);

root.add(node);

}

// 生產(chǎn)treeModel

treeModel = new DefaultTreeModel(root);

return treeModel;

}