JAVA树形结构

最新推荐文章于 2025-07-14 23:14:22 发布

原创最新推荐文章于 2025-07-14 23:14:22 发布 · 3.7k 阅读

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CC 4.0 BY-SA版权

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#java #scroll #import #exception #string #sqlserver

//分类显示数据库里的内容

package mypkg;

import java.awt.*; 

import java.awt.event.*; 

import javax.swing.*;

import javax.swing.event.*;

import java.util.*;

import java.sql.*;

import java.sql.Statement;

import javax.swing.table.*;

import javax.swing.tree.*;

/**

*

* @author Administrator

*/

public class ClassBrowse extends JFrame implements TreeSelectionListener {

Statement stmt;

ResultSet rs,rsl;

DefaultTableModel dtm;//定义数据模型

String[]title;//表头数组

JTree tree;//树

JTable table;

DefaultTreeModel treeModel = null;//定义一个默认的树模型，用于建立树

JScrollPane scroll1,scroll2;//定义两个滚动面板

JSplitPane splitPane;//定义一个分割面板

    private Object con;

public ClassBrowse(){



    try{

        stmt = ConnectServer1. con. createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);

        DefaultMutableTreeNode root = new DefaultMutableTreeNode("专业");//根

                treeModel = new DefaultTreeModel(root);//建立树模型

        initTree(root,0);//调用递归函数建立树模型

        tree = new JTree(treeModel);//利用树模型建立树

        scroll1 = new JScrollPane(tree);

        tree.addTreeSelectionListener(this);

        rs = stmt.executeQuery("select classclass.name as 班级,xsda.no as 学号,xsda.name as 姓名" +

                " from xsda,classclass where xsda.classid = classclass.id");

        ResultSetMetaData dbmd = rs.getMetaData();//得到记录集的元数据，建立表头数组

        title = new String[dbmd.getColumnCount()];

        for(int i=1;i <=dbmd.getColumnCount();i++)

            title[i-1] = dbmd.getColumnName(i);

        dtm = new DefaultTableModel(null,title);//建立表格数据模型

        table = new JTable(dtm);//利用数据模型建立表格

      scroll2 =new JScrollPane(table);

        initTable();//建立表

        splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,scroll1,scroll2);

        splitPane.setOneTouchExpandable(true);

        splitPane.setDividerLocation(200);

        this.getContentPane().add(splitPane,null);}

    catch(SQLException e){System.out.println(e);}

    setTitle("分类查询学生信息");

    setSize(500,400);

    setVisible(true);



    }

void initTree(DefaultMutableTreeNode root,int id){//这是递归函数

    DefaultMutableTreeNode node = null;//定义节点

    try{

      Statement stmt = ConnectServer1. con. createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE);

        ResultSet rs = stmt.executeQuery("select * from classclass where parent =" + id);//查询班级类表

        while(rs.next()){

            int nno = rs.getInt("id");//取得分类ID

          String nname = rs.getString("name").trim();//取得分类名称

            node = new DefaultMutableTreeNode(nname);//建立树的节点

            treeModel.insertNodeInto(node, root, root.getChildCount());//插入节点

            initTree(node,nno);}



        }

    catch(Exception e){}

    finally{

        try{

            rs.close();

        }catch(Exception e){}

                    }



}

public void valueChanged(TreeSelectionEvent e){

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

    //利用JTree的getLastSelectedPathCoponent（）方法取得目前选取的节点

    DefaultMutableTreeNode selectionNode = (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();

    String name = ((String)selectionNode.getUserObject());

    String sql = "selcet classclass.name as 班级，xsda.no as 学号,xsda.name as 姓名 from xsda,classclass where xsda.classid = classclass.id";

    if(!name.equals("专业"))

        sql=sql + "and classid in(select id from classclass where rtrim(ltrim(str(id)))like(select ltrim(rtrim(str(id)))+'%'from classclass where rtrim(ltrim(name))='"+name+"'))";

          try{

            rs = stmt.executeQuery(sql);//利用嵌套查询查出所有数据

                        initTable();

        }  catch(Exception ee){}

}

void initTable(){

    dtm.setRowCount(0);

    try{

        rs.beforeFirst();

        while(rs.next()){

            Vector v1=new Vector();

            for(int i=1;i <=title.length;i++)

                v1.addElement(rs.getString(i));

            dtm.addRow(v1);

        }

    }catch(SQLException e){e.printStackTrace();}

    dtm.fireTableStructureChanged();



}

public static void main(String arg[]){

    JFrame.setDefaultLookAndFeelDecorated(true);

    Font font = new Font("JFrame",Font.PLAIN,14);

    Enumeration keys = UIManager.getLookAndFeelDefaults().keys();

    while(keys.hasMoreElements()){

        Object key = keys.nextElement();

        if(UIManager.get(key)instanceof Font)

            UIManager.put(key, font);



    }

  if(!ConnectServer1.conn("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=xsgl","sa","")){

        JOptionPane.showMessageDialog(null, "连接数据库失败");

        System.exit(0);//关闭数据库

    }

    new ClassBrowse();



}

}