如何在java中的组合框之间使用过滤器？

问题描述

我在我的数据库中有两个表作为学期表和课程表。在学期表中有semesterId，courseId，courseName和Sdepartment（部门名称）。课表具有courseId和courseName。
我有两个组合框我的jframe.First一个是选择一个部门。第二个是选择课程。我想选择课程选定的部门。
当我选择一个部门时，我如何在组合框中调用课程名称？
我的代码;

I have two tables in my database as semester table and course table.There are semesterId,courseId,courseName and Sdepartment(department name)in semester table.Course table has courseId and courseName.I have two comboboxes my jframe.First one is for select a department.Second one is select course.I want to select course as to selected department.How can i call course name in combobox when i select a department?Here my code;

      public void coursename(){
     Session session = HibernateUtil.getSessionFactory().getCurrentSession();
     session.beginTransaction();
     //Query query= session.createQuery("select a.courseName,e.semesterId from Semester e inner join e.course as a");
     Query query= session.createQuery("FROM Senior.entity.Semester S  ");
     //for (Iterator it = query.iterate(); it.hasNext();) {
      //Object  row[] = (Object[])   it.next();
      //combocourse.addItem(new CourseItem((String)row[0], (int)row[1]));
      //}
     List <Semester>re= query.list();
     if (re.size() > 0){
     Iterator iterate= re.iterator();
     final Semester resultAccount= (Semester)iterate.next();
     combocourse.removeAllItems();
     for(Semester inv:re){
     combocourse.addItem(new CourseItem(inv.getSemesterId(),inv.getSCourse()));
     }
     }
      session.close();
   }


      public void depart(){
     Session session = HibernateUtil.getSessionFactory().getCurrentSession();
     session.beginTransaction();

     Query query= session.createQuery("FROM Senior.entity.Semester f ");
     List <Semester>results= query.list();
     if (results.size() > 0){
     Iterator iterate= results.iterator();
     final Semester resultAccount= (Semester)iterate.next();
     combodepart.removeAllItems();
     for(Semester inv:results){
     combodepart.addItem(new DepartItem(inv.getSemesterId(),inv.getSDepartment()));

         //  combodepart.addActionListener(combocourse);
               /*
            @Override
         public void actionPerformed(ActionEvent e) {
              JComboBox combocourse;
             combocourse = (JComboBox) e.getSource();
         //     Object selected = combocourse.getSelectedItem();
          Session session = HibernateUtil.getSessionFactory().getCurrentSession();
     session.beginTransaction();

     Query query= session.createQuery("FROM Senior.entity.Semester f ");
     List <Semester>results= query.list();
     if (results.size() > 0){
     Iterator iterate= results.iterator();
     final Semester resultAccount= (Semester)iterate.next();
     combodepart.removeAllItems();
     for(Semester inv:results){
     combodepart.addItem(new DepartItem(inv.getSemesterId(),inv.getSDepartment()));
         }
     });

     */

     }
     }
     session.close();
     }

推荐答案

类似于：

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;

public class ComboBoxTwo extends JPanel implements ActionListener
{
    private JComboBox<String> mainComboBox;
    private JComboBox<String> subComboBox;
    private Hashtable<String, String[]> subItems = new Hashtable<String, String[]>();

    public ComboBoxTwo()
    {
        String[] items = { "Select Item", "Color", "Shape", "Fruit" };
        mainComboBox = new JComboBox<String>( items );
        mainComboBox.addActionListener( this );

        //  prevent action events from being fired when the up/down arrow keys are used
        mainComboBox.putClientProperty("JComboBox.isTableCellEditor", Boolean.TRUE);
        add( mainComboBox );

        //  Create sub combo box with multiple models

        subComboBox = new JComboBox<String>();
        subComboBox.setPrototypeDisplayValue("XXXXXXXXXX"); // JDK1.4
        add( subComboBox );

        String[] subItems1 = { "Select Color", "Red", "Blue", "Green" };
        subItems.put(items[1], subItems1);

        String[] subItems2 = { "Select Shape", "Circle", "Square", "Triangle" };
        subItems.put(items[2], subItems2);

        String[] subItems3 = { "Select Fruit", "Apple", "Orange", "Banana" };
        subItems.put(items[3], subItems3);
    }

    public void actionPerformed(ActionEvent e)
    {
        String item = (String)mainComboBox.getSelectedItem();
        Object o = subItems.get( item );

        if (o == null)
        {
            subComboBox.setModel( new DefaultComboBoxModel() );
        }
        else
        {
            subComboBox.setModel( new DefaultComboBoxModel( (String[])o ) );
        }
    }

    private static void createAndShowUI()
    {
        JFrame frame = new JFrame("SSCCE");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.add( new ComboBoxTwo() );
        frame.setLocationByPlatform( true );
        frame.pack();
        frame.setVisible( true );
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowUI();
            }
        });
    }
}

在ActionListener中，查询数据库以获取所选部门的课程，然后创建模型。

In the ActionListener you query the database to get the courses for the selected department and then you create the model.

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