从My Sql检索JCombobox值

更新时间：2023-02-23 10:41:22
您已查看自动竞争JComboBox/JTextField ，请注意，您必须保存两个Java类，例如标准Swing JComponents 代替
I use the following code for retrieve the data from mysql Student data Base.It was work properly.It will show the student Name in combo box.The value is retrieved from Db.
My problem is the first value(first student Name which is stored in Database column) displayed in the Jcombobox name field Automatically and it was show when I click Combo Box arrow..It means when I execute this following code I see the first value(first Name) in combobox's name field nearby arrow .But I need "Student Name" Title in there.If i assign that design time but that same name displayed once again when i click that arrow.how to solve this?
My another problem is how to get select "combo box items "when I type combo box's name field.It means if I type S means the combo box items selected which is started with S.
package designstudent;
import java.awt.*;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.event.*;
import javax.swing.table.DefaultTableModel;
import java.sql.*;
import javax.swing.JOptionPane;
import javax.swing.ListSelectionModel;
import javax.swing.*;



public class FrmeA extends javax.swing.JFrame  {

    FrmA1 f1=new FrmA1();
    Statement TmpFlxTSt=null;
    ResultSet TmpFlxTRs=null;
    GContnStr GCS=new GContnStr();

public FrmeA() {
    initComponents();
}

public void combo() {

    try {
        GCS.GContnStr();
        TmpFlxTSt= GCS.GCotnStr.createStatement();
        String select = "Select StudName from studentmaster";
        TmpFlxTRs = TmpFlxTSt.executeQuery(select);

        while (TmpFlxTRs.next()) {
            cbx.addItem(TmpFlxTRs.getString("StudName"));
            Object comboitem=cbx.getSelectedItem();
        }

        TmpFlxTRs.close();
        TmpFlxTSt.close();
    }
    catch(Exception e) {
        System.out.println(e);
    }

}


@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jPanel2 = new javax.swing.JPanel();
    CmdA = new javax.swing.JButton();
    CmdE = new javax.swing.JButton();
    CmdD = new javax.swing.JButton();
    cmdQ = new javax.swing.JButton();
    jPanel3 = new javax.swing.JPanel();
    jScrollPane1 = new javax.swing.JScrollPane();
    FlxT = new javax.swing.JTable();
    cbx = new javax.swing.JComboBox();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    jPanel2.setBorder(
        javax.swing.BorderFactory.createTitledBorder(
            javax.swing.BorderFactory.createMatteBorder(
                1, 1, 1, 1, new java.awt.Color(0, 0, 255
            )
        ), "Commands")
    );

    CmdA.setFont(new java.awt.Font("Arial", 0, 10));
    CmdA.setText("+");
    CmdA.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            CmdAActionPerformed(evt);
        }
    });

    CmdE.setFont(new java.awt.Font("Arial", 0, 10));
    CmdE.setText("E");

    CmdD.setFont(new java.awt.Font("Arial", 0, 10));
    CmdD.setText("-");

    cmdQ.setFont(new java.awt.Font("Arial", 0, 10));
    cmdQ.setText("Q");
    javax.swing.GroupLayout jPanel2Layout = new javax.swing.GroupLayout(jPanel2);
    jPanel2.setLayout(jPanel2Layout);
    jPanel2Layout.setHorizontalGroup(
    jPanel2Layout.createParallelGroup(
        javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(
              CmdA,javax.swing.GroupLayout.PREFERRED_SIZE,64,javax.swing.GroupLayout.PREFERRED_SIZE
                 )
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(CmdE, javax.swing.GroupLayout.PREFERRED_SIZE, 75, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(CmdD, javax.swing.GroupLayout.DEFAULT_SIZE, 72, Short.MAX_VALUE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(cmdQ, javax.swing.GroupLayout.PREFERRED_SIZE, 72, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(35, 35, 35))
        );

        jPanel2Layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] {CmdA, CmdE, cmdQ});

        jPanel2Layout.setVerticalGroup(
            jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel2Layout.createSequentialGroup()
                .addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(CmdA, javax.swing.GroupLayout.PREFERRED_SIZE, 79, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(CmdE, javax.swing.GroupLayout.DEFAULT_SIZE, 79, Short.MAX_VALUE)
                    .addComponent(CmdD, javax.swing.GroupLayout.DEFAULT_SIZE, 79, Short.MAX_VALUE)
                    .addComponent(cmdQ, javax.swing.GroupLayout.DEFAULT_SIZE, 79, Short.MAX_VALUE))
                .addContainerGap())
        );

        jPanel3.setBorder(javax.swing.BorderFactory.createMatteBorder(1, 1, 1, 1, new java.awt.Color(0, 0, 255)));

        FlxT.setFont(new java.awt.Font("Arial", 0, 10));
        FlxT.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {

            },
            new String [] {
                "StudName", "StudClass", "StudMrk1", "StudMrk2", "StudTot", "StudRes", "StudNO", "StudId"
            }
        ) {
            Class[] types = new Class [] {
                java.lang.String.class, java.lang.Integer.class, java.lang.Integer.class, java.lang.Integer.class, java.lang.Integer.class, java.lang.String.class, java.lang.Integer.class, java.lang.Integer.class
            };

            public Class getColumnClass(int columnIndex) {
                return types [columnIndex];
            }
        });
        jScrollPane1.setViewportView(FlxT);
        FlxT.getColumnModel().getColumn(0).setResizable(false);
        FlxT.getColumnModel().getColumn(0).setPreferredWidth(150);
        FlxT.getColumnModel().getColumn(1).setResizable(false);
        FlxT.getColumnModel().getColumn(1).setPreferredWidth(70);
        FlxT.getColumnModel().getColumn(2).setResizable(false);
        FlxT.getColumnModel().getColumn(2).setPreferredWidth(70);
        FlxT.getColumnModel().getColumn(3).setResizable(false);
        FlxT.getColumnModel().getColumn(3).setPreferredWidth(70);
        FlxT.getColumnModel().getColumn(4).setResizable(false);
        FlxT.getColumnModel().getColumn(4).setPreferredWidth(70);
        FlxT.getColumnModel().getColumn(5).setResizable(false);
        FlxT.getColumnModel().getColumn(5).setPreferredWidth(70);
        FlxT.getColumnModel().getColumn(6).setMinWidth(0);
        FlxT.getColumnModel().getColumn(6).setPreferredWidth(0);
        FlxT.getColumnModel().getColumn(6).setMaxWidth(0);
        FlxT.getColumnModel().getColumn(7).setMinWidth(0);
        FlxT.getColumnModel().getColumn(7).setPreferredWidth(0);
        FlxT.getColumnModel().getColumn(7).setMaxWidth(0);

        javax.swing.GroupLayout jPanel3Layout = new javax.swing.GroupLayout(jPanel3);
        jPanel3.setLayout(jPanel3Layout);
        jPanel3Layout.setHorizontalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 1015, Short.MAX_VALUE)
            .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(jPanel3Layout.createSequentialGroup()
                    .addContainerGap()
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 995, Short.MAX_VALUE)
                    .addContainerGap()))
        );
        jPanel3Layout.setVerticalGroup(
            jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 249, Short.MAX_VALUE)
            .addGroup(jPanel3Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(jPanel3Layout.createSequentialGroup()
                    .addContainerGap()
                    .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 184, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(54, Short.MAX_VALUE)))
        );

        cbx.setEditable(true);
        cbx.setFont(new java.awt.Font("Arial", 0, 10)); // NOI18N
        cbx.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                cbxActionPerformed(evt);
            }
        });

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                .addContainerGap(657, Short.MAX_VALUE)
                .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap())
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(122, 122, 122)
                .addComponent(cbx, javax.swing.GroupLayout.PREFERRED_SIZE, 124, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(791, Short.MAX_VALUE))
            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(jPanel1Layout.createSequentialGroup()
                    .addContainerGap()
                    .addComponent(jPanel3, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                    .addContainerGap()))
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addGap(19, 19, 19)
                .addComponent(jPanel2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(18, 18, 18)
                .addComponent(cbx, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(777, Short.MAX_VALUE))
            .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(jPanel1Layout.createSequentialGroup()
                    .addGap(190, 190, 190)
                    .addComponent(jPanel3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(503, Short.MAX_VALUE)))
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 1047, Short.MAX_VALUE)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 955, Short.MAX_VALUE)
            .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                .addGroup(layout.createSequentialGroup()
                    .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)))
        );

        pack();
        java.awt.Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
        java.awt.Dimension dialogSize = getSize();
        setLocation((screenSize.width-dialogSize.width)/2,(screenSize.height-dialogSize.height)/2);
    }// </editor-fold>

    private void CmdAActionPerformed(java.awt.event.ActionEvent evt) {                                     

        f1.setVisible(true);

 // TODO add your handling code here:
    }                                    

    private void cbxActionPerformed(java.awt.event.ActionEvent evt) {

}

    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                 FrmeA fr=new FrmeA();
                 fr.combo();
                 fr.setVisible(true);
                   //fr.initconn();
            }
        });
    }

    // Variables declaration - do not modify
    private javax.swing.JButton CmdA;
    private javax.swing.JButton CmdD;
    private javax.swing.JButton CmdE;
    private javax.swing.JTable FlxT;
    private javax.swing.JComboBox cbx;
    private javax.swing.JButton cmdQ;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JPanel jPanel2;
    private javax.swing.JPanel jPanel3;
    private javax.swing.JScrollPane jScrollPane1;
    // End of variables declaration
}
you have look at AutoCompete JComboBox / JTextField, notice you have to save both Java classes, examples here, please don't use Netbeans generated code, because in most cases is too hard overrive basic methods, use Standard Swing JComponents instead
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从My Sql检索JCombobox值

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