我目前的开放结果集存在问题，无法按照我认为的方式工作。当前唯一可用的函数是 next() 方法，其他都不起作用。如果项目处于调试模式，您可以通过按钮上的 actionperformed 事件，它会触发 previous() 方法并跳过该方法中的剩余代码。如果有人能指出我正确的方向，那将不胜感激。
表格代码：
import java.sql.*;
import javax.swing.*;
public class DataNavigator extends javax.swing.JFrame {
public DataInterface db = null;
public Statement s = null;
public Connection con = null;
public PreparedStatement stmt = null;
public ResultSet rs = null;
/** Creates new form DataNavigator */
public DataNavigator() {
initComponents();
try {
db = new DataInterface("jdbc:odbc:CMPS422");
con = db.getConnection();
stmt = con.prepareStatement("SELECT * FROM Products");
rs = stmt.executeQuery();
rs.last();
} catch (Exception e) {
}
}
/** This method is called from within the constructor to
* initialize the form.
* WARNING: Do NOT modify this code. The content of this method is
* always regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
btnFirst = new javax.swing.JButton();
btnNext = new javax.swing.JButton();
btnLast = new javax.swing.JButton();
btnUpdate = new javax.swing.JButton();
btnInsert = new javax.swing.JButton();
btnDelete = new javax.swing.JButton();
txtPartNum = new javax.swing.JTextField();
txtDesc = new javax.swing.JTextField();
txtQty = new javax.swing.JTextField();
txtPrice = new javax.swing.JTextField();
jLabel1 = new javax.swing.JLabel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
btnPrev = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setTitle("Assignment 3 Data Navigator");
addWindowListener(new java.awt.event.WindowAdapter() {
public void windowOpened(java.awt.event.WindowEvent evt) {
formWindowOpened(evt);
}
});
btnFirst.setText("First");
btnFirst.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnFirstActionPerformed(evt);
}
});
btnNext.setText("Next");
btnNext.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnNextActionPerformed(evt);
}
});
btnLast.setText("Last");
btnLast.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnLastActionPerformed(evt);
}
});
btnUpdate.setText("Update");
btnInsert.setText("Insert");
btnDelete.setText("Delete");
jLabel1.setText("Part Number:");
jLabel2.setText("Description:");
jLabel3.setText("Quantity:");
jLabel4.setText("Price:");
btnPrev.setText("Prev");
btnPrev.addMouseListener(new java.awt.event.MouseAdapter() {
public void mouseClicked(java.awt.event.MouseEvent evt) {
btnPrevMouseClicked(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(btnFirst)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(2, 2, 2)
.addComponent(btnPrev)
.addGap(4, 4, 4)
.addComponent(btnNext)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnLast))
.addComponent(jLabel1)
.addComponent(jLabel2)
.addComponent(jLabel3)
.addComponent(jLabel4))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(txtPartNum)
.addGroup(layout.createSequentialGroup()
.addComponent(btnUpdate)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnInsert)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(btnDelete))
.addComponent(txtDesc)
.addComponent(txtQty)
.addComponent(txtPrice))
.addContainerGap(71, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(btnFirst)
.addComponent(btnNext)
.addComponent(btnLast)
.addComponent(btnUpdate)
.addComponent(btnInsert)
.addComponent(btnDelete)
.addComponent(btnPrev))
.addGap(66, 66, 66)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(jLabel1)
.addComponent(txtPartNum, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(txtDesc, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel2))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(txtQty, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel3))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addComponent(txtPrice, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel4))
.addContainerGap(102, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void formWindowOpened(java.awt.event.WindowEvent evt) {
try {
this.txtPartNum.setText(rs.getString("Partnum"));
this.txtDesc.setText(rs.getString("Description"));
this.txtPrice.setText(rs.getString("Price"));
this.txtQty.setText(rs.getString("Quantity"));
} catch (SQLException e) {
}
}
private void btnNextActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
try {
System.out.println(rs.getCursorName());
rs.next();
rs.moveToCurrentRow();
System.out.println(rs.getCursorName());
this.txtPartNum.setText(rs.getString("Partnum"));
this.txtDesc.setText(rs.getString("Description"));
this.txtPrice.setText(rs.getString("Price"));
this.txtQty.setText(rs.getString("Quantity"));
System.out.println(rs.getRow());
} catch (Exception e) {
}
}
private void btnLastActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
try {
rs.last();
this.txtPartNum.setText(rs.getString("Partnum"));
this.txtDesc.setText(rs.getString("Description"));
this.txtPrice.setText(rs.getString("Price"));
this.txtQty.setText(rs.getString("Quantity"));
} catch (Exception e) {
}
}
private void btnFirstActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
try {
rs.first();
this.txtPartNum.setText(rs.getString("Partnum"));
this.txtDesc.setText(rs.getString("Description"));
this.txtPrice.setText(rs.getString("Price"));
this.txtQty.setText(rs.getString("Quantity"));
} catch (Exception e) {
}
}
private void btnPrevMouseClicked(java.awt.event.MouseEvent evt) {
// TODO add your handling code here:
try {
int i;
i = rs.getRow();
if (i > 0) {
rs.previous();
System.out.println(rs.getRow());
this.txtPartNum.setText(rs.getString("Partnum"));
this.txtDesc.setText(rs.getString("Description"));
this.txtPrice.setText(rs.getString("Price"));
this.txtQty.setText(rs.getString("Quantity"));
} else {
System.out.println("FALSE");
}
} catch (Exception e) {
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new DataNavigator().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton btnDelete;
private javax.swing.JButton btnFirst;
private javax.swing.JButton btnInsert;
private javax.swing.JButton btnLast;
private javax.swing.JButton btnNext;
private javax.swing.JButton btnPrev;
private javax.swing.JButton btnUpdate;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JTextField txtDesc;
private javax.swing.JTextField txtPartNum;
private javax.swing.JTextField txtPrice;
private javax.swing.JTextField txtQty;
// End of variables declaration
}
类对象代码：
import java.sql.*;
import javax.swing.JOptionPane;
public class DataInterface {
private static DataInterface dbint = null;
private static Connection conn = null; // connection object.
private static ResultSet rset = null;
public DataInterface(String ODBCDSN) {
try
{
// See if the driver is present.
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
// Open connection to database.
conn = DriverManager.getConnection(ODBCDSN);
JOptionPane.showMessageDialog(null,
"Database successfully opened");
}
catch (Exception e)
{
JOptionPane.showMessageDialog(null, e.toString());
}
}
public Connection getConnection() { return conn; }
public static DataInterface getInstance() { return dbint; }
public static ResultSet getResultSet() { return rset; }
public PreparedStatement setStatement(String a) throws SQLException{
PreparedStatement stmt = conn.prepareStatement(a);
return stmt;
}