找不到数据Java异常 [英] No data found Java exception
问题描述
我是Java的新手,正在从事一个项目.我正在尝试使用Netbeans从MS Access检索数据.一切正常,直到我重新安装操作系统.现在,我运行代码时遇到此错误.您的帮助和建议将不胜感激
I'm new to Java and working on a project. i am trying to retrieve data from MS Access with the use of Netbeans. It was all working fine untill i reinstalled my operating system. Now wen i run the code I get this error. Your help and advice would be much appreciated
java.sql.SQLException: No data found
at sun.jdbc.odbc.JdbcOdbc.standardError(JdbcOdbc.java:7138)
at sun.jdbc.odbc.JdbcOdbc.SQLDriverConnect(JdbcOdbc.java:3073)
at sun.jdbc.odbc.JdbcOdbcConnection.initialize(JdbcOdbcConnection.java:323)
at sun.jdbc.odbc.JdbcOdbcDriver.connect(JdbcOdbcDriver.java:174)
at java.sql.DriverManager.getConnection(DriverManager.java:582)
at java.sql.DriverManager.getConnection(DriverManager.java:185)
at connect.ConnectDB(connect.java:24)
at StaffLogin.formWindowOpened(StaffLogin.java:125)
at StaffLogin.access$000(StaffLogin.java:13)
at StaffLogin$1.windowOpened(StaffLogin.java:47)
at java.awt.Window.processWindowEvent(Window.java:1859)
at javax.swing.JFrame.processWindowEvent(JFrame.java:279)
at java.awt.Window.processEvent(Window.java:1820)
at java.awt.Component.dispatchEventImpl(Component.java:4630)
at java.awt.Container.dispatchEventImpl(Container.java:2099)
at java.awt.Window.dispatchEventImpl(Window.java:2475)
at java.awt.Component.dispatchEvent(Component.java:4460)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
这是代码,我也省略了生成的代码"和外观".请让我知道是否需要这些.谢谢.
This is the code, I have left out the 'generated code' and the 'look and feel' also. please let me know if these are needed. Thanks.
import java.sql.*;
import javax.swing.*;
public class StaffLogin extends javax.swing.JFrame {
Connection conn = null;
ResultSet rs = null;
PreparedStatement pst = null;
/**
* Creates new form StaffLogin
*/
public StaffLogin() {
initComponents();
}
private void formWindowOpened(java.awt.event.WindowEvent evt) {
// TODO add your handling code here:
conn = connect.ConnectDB();
}
private void cmdloginMouseClicked(java.awt.event.MouseEvent evt) {
// TODO add your handling code here:
conn = connect.ConnectDB();
String u = txtusername.getText();
String p = txtpassword.getText();
String sql = "SELECT * FROM Staff_Table WHERE Firstname='" + u+"' and Password='"+ p+"'";
try{
pst = conn.prepareStatement(sql);
rs = pst.executeQuery();
if (rs.next()){
JOptionPane.showMessageDialog(null,"Correct Password");
Interface i = new Interface();
i.setVisible(true);
}
else
JOptionPane.showMessageDialog(null,"Invalid Username or Password");
}
catch(Exception e){
JOptionPane.showMessageDialog(null, e);
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new StaffLogin().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton cmdlogin;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JPanel jPanel1;
private javax.swing.JPasswordField txtpassword;
private javax.swing.JTextField txtusername;
// End of variables declaration
}
推荐答案
当您尝试多次读取列的值时,通常会发生这种情况.例如,这可能会引发找不到数据":
This typically occurs when you try to read the value of a column multiple times. For example, this may throw "No data found":
ResultSet rs = statement.executeQuery(sql);
while (rs.next()) {
if ("value1".equals(rs.getString("mycolumn")) || "value2".equals(rs.getString("mycolumn"))) {
这样可以正常工作:
ResultSet rs = statement.executeQuery(sql);
while (rs.next()) {
String value = rs.getString("mycolumn");
if ("value1".equals(value) || "value2".equals(value)) {
这篇关于找不到数据Java异常的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!