哪位大侠可以帮我写一段java代码！是关于根据数据库里的数据来形成一个动态树形图

这是代码，你可以自己调试一下。

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数据结构如下：

CREATE TABLE dtree (

id int,

pid int,

name varchar(200),

url varchar(200),

title varchar(200),

target varchar(200),

icon varchar(200),

iconopen varchar(200),

opened bit);

为了实现获取数据库变量功能，需要建立一个DTree类，并编译生成CLASS文件，放入\WEB-INF\classes文件夹下。

DTree类代码如下：

package work3;

public class DTree {

private int id;

private int pid;

private String name;

private String url;

private String title;

private String target;

private String icon;

private String iconOpen;

private int opened;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public int getPid() {

return pid;

}

public void setPid(int pid) {

this.pid = pid;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getUrl() {

return url;

}

public void setUrl(String url) {

this.url = url;

}

public String getTitle() {

return title;

}

public void setTitle(String title) {

this.title = title;

}

public String getTarget() {

return target;

}

public void setTarget(String target) {

this.target = target;

}

public String getIcon() {

return icon;

}

public void setIcon(String icon) {

this.icon = icon;

}

public String getIconOpen() {

return iconOpen;

}

public void setIconOpen(String iconOpen) {

this.iconOpen = iconOpen;

}

public int getOpened() {

return opened;

}

public void setOpened(int opened) {

this.opened = opened;

}

}

work3.jsp代码如下：

%@ page language="java" contentType="text/html; charset=GB18030" pageEncoding="GB18030"%

%@ page import="java.sql.*"%

jsp:useBean id='settree' scope="application" class="work3.DTree" /

!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"

""

html

head

meta http-equiv="Content-Type" content="text/html; charset=GB18030"

link rel="StyleSheet" href="dtree.css" type="text/css" /

script type="text/javascript" src="dtree.js"/script

titledTree in MySQL/title

/head

body

h2

Example

/h2

div class="dtree"

p

a href="javascript: d.openAll();"open all/a |

a href="javascript: d.closeAll();"close all/a

/p

script type="text/javascript"

!--

d = new dTree('d');

%

//驱动程序名

String driverName = "com.microsoft.jdbc.sqlserver.SQLServerDriver";

//数据库用户名

String userName = "sa";

//密码

String userPwd = "1";

//数据库名

String dbName = "master";

//表名

String tableName = "dtree";

//连接字符串

String url="jdbc:microsoft:sqlserver://localhost:1433;DatabaseName="+dbName;

//加载驱动

Class.forName(driverName).newInstance();

//连接数据库

java.sql.Connection conn = DriverManager.getConnection(url,userName,userPwd);

//得到Statement实例

java.sql.Statement statement = conn.createStatement();

//查询数据

String sql = "select * from " + tableName;

//返回结果

java.sql.ResultSet rs = statement.executeQuery(sql);

//获取变量

while (rs.next()) {

settree.setId(rs.getInt(1));

settree.setPid(rs.getInt(2));

settree.setName(rs.getString(3));

settree.setUrl(rs.getString(4));

settree.setTitle(rs.getString(5));

settree.setTarget(rs.getString(6));

settree.setIcon(rs.getString(7));

settree.setIconOpen(rs.getString(8));

settree.setOpened(rs.getInt(9));

if(settree.getPid()==0)

settree.setOpened(1);

%

d.add(%=settree.getId()%,%=settree.getPid()%,'%=settree.getName()%','%=settree.getUrl()%','%=settree.getTitle()%','%=settree.getTarget()%','','',%=settree.getOpened()%);

%

}

%

document.write(d);

//--

/script

/div

/body

/html

用java 编写一个程序,在命令行中以树状结构展现特定的文件夹及其子文件(夹)!

当然在理论上是可以实现的，可以将所有的子文件都以树形结构出来，但是文件很多的时候就会非常纠结

我理解中的树形结构大概是这样(不知道这样的图形是不是你想要的)

a

|

------------------

| | |

b c d

以下是代码，找了系统盘下子文件较少的文件夹 C:/Windows/AppPatch，当然也可以换成你自己的路径来测试

import java.io.File;

public class FileTree {

/**

* @param args

*/

public static void main(String[] args) {

try{

File file = new File("C:\\Windows\\AppPatch");

if(file.isDirectory()){

String[] fileList = file.list();

String fileName = file.getName();

int allLength = 0;

for(int i=0;ifileList.length;i++){

allLength += (fileList[i]+" ").length();

}

for(int i=0;iallLength/2;i++){

System.out.print(" ");

}

System.out.println(fileName);

for(int i=0;iallLength/2;i++){

System.out.print(" ");

}

for(int i=0;ifileName.length()/2;i++){

System.out.print(" ");

}

System.out.println("|");

for(int i=0;iallLength;i++){

System.out.print("-");

}

System.out.println("");

for(int i=0;ifileList.length;i++){

int tmpLength = fileList[i].length();

int subLength = tmpLength/2;

int lastLength = tmpLength - subLength - 1;

for(int j=0;jsubLength;j++){

System.out.print(" ");

}

System.out.print("|");

for(int j=0;jlastLength;j++){

System.out.print(" ");

}

System.out.print(" ");

}

System.out.println("");

for(int i=0;ifileList.length;i++){

System.out.print(fileList[i]+" ");

}

}

else{

System.out.println("对不起，你提供的路径不是文件夹");

}

}

catch (Exception e) {

e.printStackTrace();

}

}

}

这时可以发现输出每一个子文件/子文件夹的名字已经比较长，要是再想输出这些子文件夹里面的文件，那幅图个人觉得相当纠结，也许是我水平没够吧或是我理解错了你说的树形结构

希望以上代码对你有帮助

请问这个树状图在Java中应该怎么做？

打个比方

可以写一个Tree的类

public class Tree extends BaseDomain {

private String id;

private String key;

private String icon;

private String title;

private String value;

private String text;

private String code;

private String mtype;

private String type;

/**

* 部门的特殊个别字段

* 1.部门 / 2.岗位 的编码

*/

private String number;

private Double order;

private Double sort;

private String href;

private String component;

private ListTreeT children;

private String parentId;

private boolean hasParent = false;

private boolean hasChildren = false;

private Date createTime;

private Date modifyTime;

public void initChildren(){

this.children = new ArrayList();

}

}

在写一个工具类

public class TreeUtil {

protected TreeUtil() {

}

private final static String TOP_NODE_ID = "0";

/**

* 用于构建菜单

*

* @param nodes nodes

* @param T   T

* @return T TreeT

*/

public static T TreeT build(ListTreeT nodes) {

if (nodes == null) {

return null;

}

ListTreeT topNodes = new ArrayList();

nodes.forEach(node - {

String pid = node.getParentId();

if (pid == null || TOP_NODE_ID.equals(pid)) {

topNodes.add(node);

return;

}

for (TreeT n : nodes) {

String id = n.getId();

if (id != null id.equals(pid)) {

if (n.getChildren() == null)

n.initChildren();

n.getChildren().add(node);

node.setHasParent(true);

n.setHasChildren(true);

n.setHasParent(true);

return;

}

}

if (topNodes.isEmpty())

topNodes.add(node);

});

TreeT root = new Tree();

root.setId("0");

root.setParentId("");

root.setHasParent(false);

root.setHasChildren(true);

root.setChildren(topNodes);

root.setText("root");

return root;

}

}

写完了这两个在写业务层

一个构建书的方法

private void buildTrees(List trees, List menus, List ids) {

menus.forEach(menu - {

ids.add(menu.getId().toString());

Tree tree = new Tree();

tree.setId(menu.getId().toString());

tree.setKey(tree.getId());

tree.setParentId(menu.getParentId().toString());

tree.setText(menu.getName());

tree.setTitle(tree.getText());

tree.setIcon(menu.getIcon());

tree.setComponent(menu.getComponent());

tree.setCreateTime(menu.getCreateTime());

tree.setCreateTime(menu.getCreateTime());

tree.setHref(menu.getHref());

tree.setSort(menu.getSort());

tree.setCode(menu.getCode());

tree.setMtype(menu.getMtype());

trees.add(tree);

});

}

MapString, Object result = new HashMap();

ListDept depts = findDepts(dept, request);

ListTreeDept trees = new ArrayList();

buildTrees(trees, depts);

TreeDept deptTree = TreeUtil.build(trees);

result.put("rows", deptTree);

result.put("total", depts.size());

求 java 刷新 JScrollPane中jtree树状图的方法

java 中actionPerformed的方法可以刷新jtree树状图的，具体做法是在actionPerformed的方法尾部加上JSPcrollPanel.updateUI();

代码如下:

import javax.swing.JFrame;

import javax.swing.JTree;

import javax.swing.event.TreeSelectionEvent;

import javax.swing.event.TreeSelectionListener;

import javax.swing.tree.DefaultMutableTreeNode;

public class TreeDemo {

public static void main(String[] args) {

// 创建没有父节点和子节点、但允许有子节点的树节点，并使用指定的用户对象对它进行初始化。

// public DefaultMutableTreeNode(Object userObject)

DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("软件部");

node1.add(new DefaultMutableTreeNode(new User("小花")));

node1.add(new DefaultMutableTreeNode(new User("小虎")));

node1.add(new DefaultMutableTreeNode(new User("小龙")));

DefaultMutableTreeNode node2 = new DefaultMutableTreeNode("销售部");

node2.add(new DefaultMutableTreeNode(new User("小叶")));

node2.add(new DefaultMutableTreeNode(new User("小雯")));

node2.add(new DefaultMutableTreeNode(new User("小夏")));

DefaultMutableTreeNode top = new DefaultMutableTreeNode("职员管理");

top.add(new DefaultMutableTreeNode(new User("总经理")));

top.add(node1);

top.add(node2);

final JTree tree = new JTree(top);

JFrame f = new JFrame("JTreeDemo");

f.add(tree);

f.setSize(300, 300);

f.setVisible(true);

f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

// 添加选择事件

tree.addTreeSelectionListener(new TreeSelectionListener() {

@Override

public void valueChanged(TreeSelectionEvent e) {

DefaultMutableTreeNode node = (DefaultMutableTreeNode) tree

.getLastSelectedPathComponent();

if (node == null)

return;

Object object = node.getUserObject();

if (node.isLeaf()) {

User user = (User) object;

System.out.println("你选择了：" + user.toString());

}

}

});

}

}

class User {

private String name;

public User(String n) {

name = n;

}

// 重点在toString，节点的显示文本就是toString

public String toString() {

return name;

}

}

名称栏目：树状图java代码 java 树状图
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