这是我的系统分析和设计类中的一个项目，所以我对Java相当陌生，只上过一门基础课程，数据库，从未上过课程。这是我第一次在这个网站上发帖，所以如果代码格式有点乱，我很抱歉。
这是我的类加载数据库的代码。
import java.sql.*;
import javax.swing.*;
public class javaconnect {
Connection conn=null;
public static Connection ConnecrDB()
{
try{
Class.forName("org.sqlite.JDBC").newInstance();
Connection conn=DriverManager.getConnection
("jdbc:sqlite:Macintosh HD\Users\matthewslauson\Documents\workspace\scheduleSystem.sqlite" );
JOptionPane.showMessageDialog(null, "Connection Successful");
return conn;
}catch(Exception e)
{
JOptionPane.showMessageDialog(null, e);
return null;
}
}
}
与数据库的连接运行良好，但当我尝试输入用户名和密码时，我会收到错误。这是我登录屏幕的代码。我向您保证，表Employeeinfo确实存在于scheduleSystem.sqlite.中
import java.sql.*;
import javax.swing.*;
public class NewJFrame extends javax.swing.JFrame {
Connection conn=null;
ResultSet rs =null;
PreparedStatement pst=null;
/**
* Creates new form NewJFrame
*/
public NewJFrame() {
initComponents();
conn=javaconnect.ConnecrDB();
}
/**
* 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() {
jPanel1 = new javax.swing.JPanel();
txtUsername = new javax.swing.JTextField();
txtPassword = new javax.swing.JPasswordField();
btnLogin = new javax.swing.JButton();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
txtUsername.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
txtUsernameActionPerformed(evt);
}
});
txtPassword.setText("jPasswordField1");
btnLogin.setText("Login");
btnLogin.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
btnLoginActionPerformed(evt);
}
});
jLabel1.setFont(new java.awt.Font("Sinhala Sangam MN", 1, 36)); // NOI18N
jLabel1.setText("Welcome");
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(151, 151, 151)
.addComponent(btnLogin)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addContainerGap(128, Short.MAX_VALUE)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(txtPassword, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(txtUsername, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(128, 128, 128))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addComponent(jLabel1)
.addGap(117, 117, 117))))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(36, 36, 36)
.addComponent(jLabel1)
.addGap(32, 32, 32)
.addComponent(txtUsername, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(txtPassword, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(btnLogin)
.addContainerGap(61, Short.MAX_VALUE))
);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
);
pack();
}// </editor-fold>
private void txtUsernameActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void btnLoginActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
String sql ="SELECT * FROM Employeeinfo WHERE uName=? AND pWord=?";
try{
pst=conn.prepareStatement(sql);
pst.setString(1, txtUsername.getText());
pst.setString(2, txtPassword.getText());
rs=pst.executeQuery();
if(rs.next()){
JOptionPane.showMessageDialog(null, "login credentials valid");
}
else{
JOptionPane.showMessageDialog(null, "login credentials invalid");
}
}catch(Exception e)
{
JOptionPane.showMessageDialog(null, e);
JOptionPane.showMessageDialog(null, e);
}
}
/**
* @param args the command line arguments
*/
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(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame.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 NewJFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton btnLogin;
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel jPanel1;
private javax.swing.JPasswordField txtPassword;
private javax.swing.JTextField txtUsername;
// End of variables declaration
}
这是我第一次在这个网站上发帖，所以如果我的代码有点乱，我很抱歉。
我不确定它在sqlite中是否相似，但在Postgresql中，必须在表名前面加上模式。例如：schema_name.Emplateeinfo