I am new to Java and trying to compile this code but run into these errors:
ava -cp .;C:\app\client\wtolentino\product\19.0.0\client_1\jdbc\lib\ojdbc8.jar main.java
main.java:7: error: cannot find symbol
new LoginScreen();
main.java
import javax.swing.*;
public class Main {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new LoginScreen();
}
});
}
}
LoginScreen.java
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class LoginScreen extends JFrame {
private JTextField usernameField;
private JPasswordField passwordField;
public static String user;
public static String password;
public LoginScreen() {
setTitle("Login");
setSize(300, 150);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
JPanel panel = new JPanel();
add(panel);
placeComponents(panel);
setVisible(true);
}
private void placeComponents(JPanel panel) {
panel.setLayout(null);
JLabel userLabel = new JLabel("User:");
userLabel.setBounds(10, 20, 80, 25);
panel.add(userLabel);
usernameField = new JTextField(20);
usernameField.setBounds(100, 20, 165, 25);
panel.add(usernameField);
JLabel passwordLabel = new JLabel("Password:");
passwordLabel.setBounds(10, 50, 80, 25);
panel.add(passwordLabel);
passwordField = new JPasswordField(20);
passwordField.setBounds(100, 50, 165, 25);
panel.add(passwordField);
JButton loginButton = new JButton("Login");
loginButton.setBounds(10, 80, 80, 25);
panel.add(loginButton);
loginButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String userInput = usernameField.getText();
String passInput = new String(passwordField.getPassword());
if (authenticate(userInput, passInput)) {
dispose();
new DataEntryScreen();
} else {
JOptionPane.showMessageDialog(null, "Invalid login. Please try again.");
}
}
});
}
private boolean authenticate(String userInput, String passInput) {
user = userInput;
password = passInput;
String url = "jdbc:oracle:thin:@//host:1521/DEV"
try (Connection conn = DriverManager.getConnection(url, user, password)) {
return conn != null;
} catch (SQLException e) {
e.printStackTrace();
return false;
}
}
}
DataEntryScreen.java
import java.sql.*;
import javax.swing.*;
public class DataEntryScreen extends JFrame {
private JComboBox<String> tableDropdown;
private JTextField usernameField;
private JTextField firstNameField;
private JTextField middleNameField;
private JTextField lastNameField;
private JTextField emailField;
private JTable dataTable;
public DataEntryScreen() {
setTitle("User Account Reference Data Entry");
setSize(800, 500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
JPanel panel = new JPanel();
add(panel);
placeComponents(panel);
setVisible(true);
}
private void placeComponents(JPanel panel) {
panel.setLayout(null);
JLabel tableLabel = new JLabel("Select Table:");
tableLabel.setBounds(10, 10, 100, 25);
panel.add(tableLabel);
tableDropdown = new JComboBox<>();
tableDropdown.setBounds(120, 10, 200, 25);
loadTables(); // Load table names dynamically
panel.add(tableDropdown);
JButton showDataButton = new JButton("Show Data");
showDataButton.setBounds(330, 10, 120, 25);
panel.add(showDataButton);
showDataButton.addActionListener(e -> showTableData());
JLabel usernameLabel = new JLabel("Username:");
usernameLabel.setBounds(10, 50, 100, 25);
panel.add(usernameLabel);
usernameField = new JTextField(20);
usernameField.setBounds(120, 50, 165, 25);
panel.add(usernameField);
JLabel firstNameLabel = new JLabel("First Name:");
firstNameLabel.setBounds(10, 90, 100, 25);
panel.add(firstNameLabel);
firstNameField = new JTextField(20);
firstNameField.setBounds(120, 90, 165, 25);
panel.add(firstNameField);
JLabel middleNameLabel = new JLabel("Middle Name:");
middleNameLabel.setBounds(10, 130, 100, 25);
panel.add(middleNameLabel);
middleNameField = new JTextField(20);
middleNameField.setBounds(120, 130, 165, 25);
panel.add(middleNameField);
JLabel lastNameLabel = new JLabel("Last Name:");
lastNameLabel.setBounds(10, 170, 100, 25);
panel.add(lastNameLabel);
lastNameField = new JTextField(20);
lastNameField.setBounds(120, 170, 165, 25);
panel.add(lastNameField);
JLabel emailLabel = new JLabel("Email Address:");
emailLabel.setBounds(10, 210, 100, 25);
panel.add(emailLabel);
emailField = new JTextField(20);
emailField.setBounds(120, 210, 165, 25);
panel.add(emailField);
JButton insertButton = new JButton("Insert");
insertButton.setBounds(10, 260, 80, 25);
panel.add(insertButton);
insertButton.addActionListener(e -> insertData());
/*JButton deleteButton = new JButton("Delete");
deleteButton.setBounds(100, 260, 80, 25);
panel.add(deleteButton);
deleteButton.addActionListener(e -> deleteData());
JButton updateButton = new JButton("Update");
updateButton.setBounds(190, 260, 80, 25);
panel.add(updateButton);
updateButton.addActionListener(e -> updateData());*/
dataTable = new JTable();
JScrollPane scrollPane = new JScrollPane(dataTable);
scrollPane.setBounds(10, 300, 760, 150);
panel.add(scrollPane);
}
private void loadTables() {
String url = "jdbc:oracle:thin:@//host:1521/DEV"
try (Connection conn = DriverManager.getConnection(url, LoginScreen.user, LoginScreen.password)) {
DatabaseMetaData metaData = conn.getMetaData();
ResultSet tables = metaData.getTables(null, null, "%", new String[] {"TABLE"});
while (tables.next()) {
String tableName = tables.getString("TABLE_NAME");
String table_schem = tables.getString("TABLE_SCHEM");
tableDropdown.addItem(table_schem + "." + tableName); // Add table name to the dropdown
}
} catch (SQLException e) {
e.printStackTrace();
JOptionPane.showMessageDialog(this, "Error loading tables: " + e.getMessage());
}
}
private void showTableData() {
String selectedTable = (String) tableDropdown.getSelectedItem();
String url = "jdbc:oracle:thin:@//host:1521/DEV"
try (Connection conn = DriverManager.getConnection(url, LoginScreen.user, LoginScreen.password)) {
String query = "SELECT * FROM " + selectedTable;
PreparedStatement stmt = conn.prepareStatement(query);
ResultSet rs = stmt.executeQuery();
ResultSetMetaData metaData = rs.getMetaData();
int columnCount = metaData.getColumnCount();
// Fetch column names
String[] columnNames = new String[columnCount];
for (int i = 1; i <= columnCount; i++) {
columnNames[i - 1] = metaData.getColumnName(i);
}
// Fetch rows dynamically
java.util.List<Object[]> rows = new java.util.ArrayList<>();
while (rs.next()) {
Object[] rowData = new Object[columnCount];
for (int colIndex = 0; colIndex < columnCount; colIndex++) {
rowData[colIndex] = rs.getObject(colIndex + 1);
}
rows.add(rowData);
}
// Convert list to array for JTable
Object[][] data = rows.toArray(new Object[0][]);
// Update table model
dataTable.setModel(new javax.swing.table.DefaultTableModel(data, columnNames));
} catch (SQLException e) {
e.printStackTrace();
JOptionPane.showMessageDialog(this, "Error displaying data: " + e.getMessage());
}
}
private void insertData() {
executeQuery("INSERT INTO " + tableDropdown.getSelectedItem() +
" (USERNAME, FIRST_NAME, MIDDLE_NAME, LAST_NAME, EMAIL_ADDRESS) VALUES (?, ?, ?, ?, ?)",
true);
}
/*private void deleteData() {
executeQuery("DELETE FROM " + tableDropdown.getSelectedItem() + " WHERE USERNAME = ?", false);
}
private void updateData() {
executeQuery("UPDATE " + tableDropdown.getSelectedItem() +
" SET EMAIL_ADDRESS = ? WHERE USERNAME = ?", false);
}*/
private void executeQuery(String query, boolean isInsert) {
String url = "jdbc:oracle:thin:@//host:1521/DEV"
try (Connection conn = DriverManager.getConnection(url, LoginScreen.user, LoginScreen.password);
PreparedStatement stmt = conn.prepareStatement(query)) {
stmt.setString(1, usernameField.getText());
if (isInsert) {
stmt.setString(2, firstNameField.getText());
stmt.setString(3, middleNameField.getText());
stmt.setString(4, lastNameField.getText());
stmt.setString(5, emailField.getText());
} else {
stmt.setString(2, emailField.getText());
}
stmt.executeUpdate();
JOptionPane.showMessageDialog(this, "Operation successful.");
} catch (SQLException e) {
e.printStackTrace();
JOptionPane.showMessageDialog(this, "Error: " + e.getMessage());
}
}
}
However, when I asked a co-worker to compile it on her machine it is working. I am not sure what is missing. Please advise. Thank you.