Question

我正在尝试创建一个支票打印应用程序，其中我有四个ComboBox。所有这些都是从oracle数据库获取数据。 ComboBox1检索所有银行的名称，而ComboBox2检索所选银行的所有帐户。 ComboBox3检索范围的所有from_cheque数字，最后一个检索范围的所有to_cheque数字。
现在的问题是当我选择帐号时。引发了一个异常＆＃34; java.sql.SQLException：Closed Resultset：next ＆＃34;并且它只在ComboBox3中带来一行，而数据库中存储的行不止一行，并且不会在最后一个ComboBox中带来任何结果。代码如下所述。

package frame;

import java.beans.Statement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import javax.swing.*;
import java.io.*;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 *
 * @author talha
 */
public class print_cheque extends javax.swing.JFrame {

    Connection con = null;
    java.sql.Statement st = null;
    java.sql.Statement st1 = null;
    java.sql.Statement st2 = null;
    java.sql.Statement st3 = null;

    /**
     * Creates new form print_cheque
     */
    public print_cheque() {
        initComponents();

        //Statement st =  null;
        String query = "Select bnk_nm from d_bank_mst";

        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            con = DriverManager.getConnection("jdbc:oracle:thin:@191.1.1.220:1521:abc10g", "payablek", "payablek");
            System.out.println("connection successful");

            st = con.createStatement();
            ResultSet rs = st.executeQuery(query);
            int itemCount = jComboBox1.getItemCount();
            jComboBox1.addItem("--Select Company--");
            for (int i = 0; i < itemCount; i++) {
                jComboBox1.removeItemAt(0);
            }

            while (rs.next()) {
                String bank = rs.getString(1);
                jComboBox1.addItem(bank);
            }

            //JOptionPane.showMessageDialog(this, i);
            //con.close();
            st.close();
            rs.close();

        } catch (Exception e) {
            JOptionPane.showMessageDialog(this, e);
        }

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

        jComboBox1 = new javax.swing.JComboBox<>();
        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jComboBox2 = new javax.swing.JComboBox<>();
        jLabel3 = new javax.swing.JLabel();
        jLabel4 = new javax.swing.JLabel();
        jRadioButton1 = new javax.swing.JRadioButton();
        jComboBox4 = new javax.swing.JComboBox<>();
        jComboBox6 = new javax.swing.JComboBox<>();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        jComboBox1.setToolTipText("");
        jComboBox1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jComboBox1ActionPerformed(evt);
            }
        });

        jLabel1.setText("Bank Name");

        jLabel2.setText("Account No");

        jComboBox2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jComboBox2ActionPerformed(evt);
            }
        });

        jLabel3.setText("From Cheque No");

        jLabel4.setText("To Cheque No");

        jRadioButton1.setText("Cash");
        jRadioButton1.addActionListener(new java.awt.event.ActionListener() {


    private void jComboBox1ActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
        //JOptionPane.showConfirmDialog(null, "ello");       // TODO add your handling code here:
        JComboBox cb = (JComboBox) evt.getSource();
        int itemCount = jComboBox2.getItemCount();
        String banknm = (String) cb.getSelectedItem();// = "'%Sindh Bank Ltd%'";
        JOptionPane.showMessageDialog(null, banknm);
        jComboBox2.addItem("--Select Account--");
        try {
            st1 = con.createStatement();
        } catch (Exception ex) {
            Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
        }

        JOptionPane.showMessageDialog(null, 1);
        ResultSet rs2 = null;

        String query2 = "Select distinct c.ac_no  "
                + "from d_chq_mst c, d_bank_mst d "
                + "where d.bnk_nm like '%" + banknm + "%'"
                + "and  c.bnk_cd= d.bnk_cd ";//" + banknm + "
        try {
            JOptionPane.showMessageDialog(null, 2);
            //int itemCount = jComboBox2.getItemCount();
            for (int i = 0; i < itemCount; i++) {
                jComboBox2.removeItemAt(1);
            }
            rs2 = st1.executeQuery(query2);
            JOptionPane.showMessageDialog(null, 3);
            while (rs2.next()) {
                try {
                    //JOptionPane.showMessageDialog(null, 4);
                    jComboBox2.addItem(rs2.getString(1));
                } catch (SQLException ex) {
                    Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
                }
            }
            st1.close();
            rs2.close();
        } catch (SQLException ex) {
            Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
        }

    }                                          

    private void jRadioButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                              
        // TODO add your handling code here:
    }                                             

    private void jComboBox2ActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
        //int t = 0;
        JComboBox cb1 = (JComboBox) evt.getSource();
        jComboBox4.addItem("--Select From Cheque Number--");
        String acnt = (String) cb1.getSelectedItem();
        /*if((t == 0)&&!(jComboBox2.equals(null)) ){
            cb1.setSelectedItem(null);
        }*/

        JOptionPane.showMessageDialog(null, acnt);

        try {
            st2 = con.createStatement();
        } catch (Exception ex) {
            //Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
            ex.printStackTrace();
        }
        ResultSet rs3 = null;
        String query3 = "select distinct d.chq_from "
                + "from d_chq_mst d, d_chq_dtl e  "
                + " where e.ac_no= '" + acnt + "'"
                + " and d.ac_no = e.ac_no ";
        try {
            rs3 = st2.executeQuery(query3);
            int itemCount2 = jComboBox4.getItemCount();
            /*for (int i = 0; i < itemCount2; i++) {
                //jComboBox4.removeItemAt(0);
                JOptionPane.showMessageDialog(this, i);
            }*/
            while (rs3.next()) {
                try {
                    JOptionPane.showMessageDialog(null, "item Count**" + itemCount2);
                    jComboBox4.addItem(rs3.getString(1));
                } catch (SQLException ex) {
                    //Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
                    ex.printStackTrace();
                }

                st2.close();
                rs3.close();

            }
        } catch (Exception ex) {
            //Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
            ex.printStackTrace();
        }
        //t++;

    }                                          

    private void jComboBox4ActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
        jComboBox6.addItem("--Select To Cheque Number--");
        JComboBox cb2 = (JComboBox) evt.getSource();

        String account = (String) cb2.getSelectedItem();

        //JOptionPane.showMessageDialog(null, acnt);
        try {
            st3 = con.createStatement();
        } catch (Exception ex) {
            //Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
            ex.printStackTrace();
        }
        ResultSet rs4 = null;
        String query3 = "select distinct d.chq_to  "
                + "from d_chq_mst d, d_chq_dtl e  "
                + "where d.ac_no= '" + account + "'"
                + "and d.ac_no= '" + account + "'";

        //+ "where d.ac_no = '" + acnt + "'";
        try {
            rs4 = st3.executeQuery(query3);
            int itemCount3 = jComboBox6.getItemCount();
            /*for (int i = 0; i < itemCount3; i++) {
                jComboBox6.removeItemAt(0);
            }*/
            while (rs4.next()) {
                try {
                    JOptionPane.showMessageDialog(null, rs4.getString(1));
                    jComboBox6.addItem(rs4.getString(1));
                } catch (SQLException ex) {
                    Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
                    ex.printStackTrace();
                }

                st3.close();
                rs4.close();

            }

        } catch (Exception ex) {
            //Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
            ex.printStackTrace();
        }
    }                                          

    private void jComboBox6ActionPerformed(java.awt.event.ActionEvent evt) {                                           
        // TODO add your handling code here:
    } 
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(print_cheque.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(print_cheque.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(print_cheque.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(print_cheque.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new print_cheque().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JComboBox<String> jComboBox1;
    private javax.swing.JComboBox<String> jComboBox2;
    private javax.swing.JComboBox<String> jComboBox4;
    private javax.swing.JComboBox<String> jComboBox6;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JRadioButton jRadioButton1;
    // End of variables declaration                   
}

这是Stack Trace。

运行：连接成功java.sql.SQLException：关闭结果集：接下来 oracle.jdbc.driver.InsensitiveScrollableResultSet.next（InsensitiveScrollableResultSet.java:558）在 frame.print_cheque.jComboBox2ActionPerformed（print_cheque.java:262） at frame.print_cheque.access $ 100（print_cheque.java:23）at frame.print_cheque $ 2.actionPerformed（print_cheque.java:103）at javax.swing.JComboBox.fireActionEvent（JComboBox.java:1260）at javax.swing.JComboBox.setSelectedItem（JComboBox.java:588）at javax.swing.JComboBox.setSelectedIndex（JComboBox.java:624）at javax.swing.plaf.basic.BasicComboBoxUI.selectNextPossibleValue（BasicComboBoxUI.java:1124）在 javax.swing.plaf.basic.BasicComboBoxUI中的$ Actions.actionPerformed（BasicComboBoxUI.java:1528）在javax.swing.SwingUtilities.notifyAction（SwingUtilities.java:1662）在javax.swing.JComponent.processKeyBinding（JComponent.java:2879）at javax.swing.JComboBox.processKeyBinding（JComboBox.java:1425）at javax.swing.JComponent.processKeyBindings（JComponent.java:2940）at javax.swing.JComponent.processKeyEvent（JComponent.java:2842）at javax.swing.JComboBox.processKeyEvent（JComboBox.java:1417）at java.awt.Component.processEvent（Component.java:6293）at java.awt.Container.processEvent（Container.java:2229）at java.awt.Component.dispatchEventImpl（Component.java:4872）at java.awt.Container.dispatchEventImpl（Container.java:2287）at java.awt.Component.dispatchEvent（Component.java:4698）at java.awt.KeyboardFocusManager.redispatchEvent（KeyboardFocusManager.java:1887）在 java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent（DefaultKeyboardFocusManager.java:762）在 java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent（DefaultKeyboardFocusManager.java:1027）在 java.awt.DefaultKeyboardFocusManager.typeAheadAssertions（DefaultKeyboardFocusManager.java:899）在 java.awt.DefaultKeyboardFocusManager.dispatchEvent（DefaultKeyboardFocusManager.java:727）在java.awt.Component.dispatchEventImpl（Component.java:4742）at java.awt.Container.dispatchEventImpl（Container.java:2287）at java.awt.Window.dispatchEventImpl（Window.java:2719）at java.awt.Component.dispatchEvent（Component.java:4698）at java.awt.EventQueue.dispatchEventImpl（EventQueue.java:747）at at java.awt.EventQueue.access $ 300（EventQueue.java:103）at java.awt.EventQueue $ 3.run（EventQueue.java:706）at java.awt.EventQueue $ 3.run（EventQueue.java:704）at java.security.AccessController.doPrivileged（Native Method）at java.security.ProtectionDomain $ 1.doIntersectionPrivilege（ProtectionDomain.java:76）在 java.security.ProtectionDomain $ 1.doIntersectionPrivilege（ProtectionDomain.java:87）在java.awt.EventQueue $ 4.run（EventQueue.java:720）at java.awt.EventQueue $ 4.run（EventQueue.java:718）at java.security.AccessController.doPrivileged（Native Method）at java.security.ProtectionDomain $ 1.doIntersectionPrivilege（ProtectionDomain.java:76）在java.awt.EventQueue.dispatchEvent（EventQueue.java:717）at java.awt.EventDispatchThread.pumpOneEventForFilters（EventDispatchThread.java:242）在 java.awt.EventDispatchThread.pumpEventsForFilter（EventDispatchThread.java:161）在 java.awt.EventDispatchThread.pumpEventsForHierarchy（EventDispatchThread.java:150）在 java.awt.EventDispatchThread.pumpEvents（EventDispatchThread.java:146）在 java.awt.EventDispatchThread.pumpEvents（EventDispatchThread.java:138） at java.awt.EventDispatchThread.run（EventDispatchThread.java:91）

Answer 1

你的错误在这里：

while (rs3.next()) {
    ...
    st2.close();
    rs3.close();
}

您在while循环中关闭ResultSet而不是在循环外

NB：您的关闭序列不正确您应该首先关闭结果集，然后关闭语句，最后关闭连接（如果不再需要）。换句话说，关闭序列必须是反转的创建序列。

你的代码应该是这样的：

try {
    ...
} catch (Exception ex) {
    //Logger.getLogger(print_cheque.class.getName()).log(Level.SEVERE, null, ex);
    ex.printStackTrace();
} finally {
    // Close first the result set
    if (rs4 != null) {
        rs4.close();  
    }
    // The close your statement
    if (st3 != null) {
        st3.close(); 
    } 
}

假设您使用的是Java 7或更高版本，可以考虑使用try-with-resources语句

java.sql.SQLException：Closed Resultset：接下来从ComboBox

1 个答案: