如何从数据库中插入具有值的组合框我想从数据库中选择并添加到组合框中我有两个班级：
constructor Database（）第一类
//constructeur
Database()
{
void remplir_Jcomb() {
Connection conn = null;
Statement st = null;
String rq1 = "SELECT region FROM rg";
String rq2 = "SELECT ACTELS FROM rg";
// - Paramètres de connexion à la base de données
String url = "jdbc:mysql://localhost/réseau";
String login = "root";
String password = "";
String driver = "com.mysql.jdbc.Driver";
try {
//comboBox_gouver.removeAllItems();
try {
Class.forName(driver);
conn = DriverManager.getConnection(url,login,password);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
st = conn.createStatement();
ResultSet rs1 = st.executeQuery(rq1);
ResultSet rs2 = st.executeQuery(rq2);
while ((rs1.next())&&(rs2.next())) {
comboBox_gouver.addItem(rs1.getString(1));
comboBox_ACTELS.addItem(rs2.getString(1));
}
st.close();
rs1.close();
rs2.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();}
}
}
包含两个JComboBox的第二个接口摆动类调用构造函数Database（）
private Database BD= new Database();
public Region() {
//first JComboBox
comboBox_gouver = new JComboBox<String>();
BD.remplir_Jcomb();
sl_contentPanel.putConstraint(SpringLayout.NORTH, lbl_gouver, 5, SpringLayout.NORTH, comboBox_gouver);
sl_contentPanel.putConstraint(SpringLayout.NORTH, comboBox_gouver, 5, SpringLayout.NORTH, contentPanel);
sl_contentPanel.putConstraint(SpringLayout.WEST, comboBox_gouver, 16, SpringLayout.EAST, lbl_gouver);
sl_contentPanel.putConstraint(SpringLayout.EAST, comboBox_gouver, -26, SpringLayout.EAST, contentPanel);
contentPanel.add(comboBox_gouver);
comboBox_ACTELS = new JComboBox<String>();
sl_contentPanel.putConstraint(SpringLayout.NORTH, lbl_ACTELS, 5, SpringLayout.NORTH, comboBox_ACTELS);
sl_contentPanel.putConstraint(SpringLayout.NORTH, comboBox_ACTELS, 6, SpringLayout.SOUTH, comboBox_gouver);
sl_contentPanel.putConstraint(SpringLayout.WEST, comboBox_ACTELS, 90, SpringLayout.EAST, lbl_ACTELS);
sl_contentPanel.putConstraint(SpringLayout.SOUTH, comboBox_ACTELS, -29, SpringLayout.SOUTH, contentPanel);
sl_contentPanel.putConstraint(SpringLayout.EAST, comboBox_ACTELS, -26, SpringLayout.EAST, contentPanel);
contentPanel.add(comboBox_ACTELS);
}}
erreur：
java.sql.SQLException: Operation not allowed after ResultSet closed
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:987)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:982)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:927)
at com.mysql.jdbc.ResultSetImpl.checkClosed(ResultSetImpl.java:794)
at com.mysql.jdbc.ResultSetImpl.next(ResultSetImpl.java:7139)
at tn.pack.ACTEL.Database.remplir_Jcomb(Database.java:94)
at tn.pack.ACTEL.Region.<init>(Region.java:75)
at tn.pack.ACTEL.Region.main(Region.java:41)
finally block关闭打开的对象，因为在所有情况下都将执行此代码）void whatever {
Connection conn = null;
Statement st1 = null;
try {
st1 = conn.createStatement();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
st1.close();
rs1.close();
rs2.close();
conn.close();
} catch (SQLException ex) {
//
}
}
}
2]在Db语句中填充数据至（注意Java6 / Java7之间的API差异），
ComboBoxModel-JComboBox(ComboBoxModel aModel)/JComboBox(ComboBoxModel<E> aModel)arrays of Objects/Elements-JComboBox(Object[] items)/JComboBox(E[] items)Vector of Objects/Elements-JComboBox(Vector items)/JComboBox(Vector<E> items)如果Sql块结束，则将数组类型添加到JComboBox
编辑：
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
import javax.swing.*;
public class ComboBoxListeners {
private JFrame f;
private JComboBox comboBox;
private JLabel label = new JLabel();
private DefaultComboBoxModel comboBoxModel = new DefaultComboBoxModel();
public ComboBoxListeners() {
comboBox = new JComboBox(comboBoxModel);
comboBox.addItemListener(new ItemListener() {
@Override
public void itemStateChanged(ItemEvent e) {
if ((e.getStateChange() == ItemEvent.SELECTED)) {
String str = comboBox.getSelectedItem().toString();
label.setText("Selected Value From JComboBox is : " + str);
}
}
});
label.setPreferredSize(new Dimension(400, 30));
JButton btnAdd = new JButton(new AbstractAction("Append Items") {
private static final long serialVersionUID = 1L;
@Override
public void actionPerformed(ActionEvent e) {
addNewItemsFromDatabase();
}
});
JButton btnRefresh = new JButton(new AbstractAction("Refresh Items") {
private static final long serialVersionUID = 1L;
@Override
public void actionPerformed(ActionEvent e) {
refreshItemsFromDatabase();
}
});
f = new JFrame("ComboBox ItemListeners");
f.setLayout(new GridLayout(0, 1, 15, 15));
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.add(comboBox);
f.add(label);
f.add(btnAdd);
f.add(btnRefresh);
f.setLocation(150, 150);
f.pack();
f.setVisible(true);
}
public void addNewItemsFromDatabase() {
ArrayList<Integer> ageList = new ArrayList<Integer>();
for (int i = 1; i <= 5; ++i) {
ageList.add(i);
}
for (final Integer i : ageList) {
EventQueue.invokeLater(new Runnable() {
public void run() {// updates to the Swing GUI must be done on EDT
comboBoxModel.addElement(i);
}
});
}
}
public void refreshItemsFromDatabase() {
comboBoxModel = new DefaultComboBoxModel();
ArrayList<Integer> ageList = new ArrayList<Integer>();
for (int i = 1; i <= 5; ++i) {
ageList.add(i);
}
for (final Integer i : ageList) {
EventQueue.invokeLater(new Runnable() {
public void run() {// updates to the Swing GUI must be done on EDT
comboBoxModel.addElement(i);
}
});
}
comboBox.setModel(comboBoxModel);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
ComboBoxListeners comboBoxListeners = new ComboBoxListeners();
}
});
}
}
void remplir_Jcomb() {
Connection conn = null;
Statement st1 = null;
Statement st2 = null;
String rq1 = "SELECT region FROM rg";
String rq2 = "SELECT ACTELS FROM rg";
//Rest of your code here
try {
// snipping off some more code
//...
st1 = conn.createStatement();
st2 = conn.createStatement();
ResultSet rs1 = st1.executeQuery(rq1);
ResultSet rs2 = st2.executeQuery(rq2);
while ((rs1.next())&&(rs2.next())) {
comboBox_gouver.addItem(rs1.getString(1));
comboBox_ACTELS.addItem(rs2.getString(1));
}
} catch (SQLException e) {
e.printStackTrace();
}
finally{
st1.close();
st1.close();
rs1.close();
rs2.close();
conn.close();
}
}
皮拉好
维达很好
但是公鸡很棒！>
公鸡*
烹饪？
cokE？
GANZA
Peílius