如何将NetBeans 12连接到Access数据库/ SQL数据库

如何解决如何将NetBeans 12连接到Access数据库/ SQL数据库

我对netbeans比较陌生，无法弄清楚如何在Access上连接到我的数据库。我正在使用Netbeans 12，并且我的数据库以及ucanaccess-5.0.0都在我的源文件夹中

这是我必须连接到数据库的编码：

public class DatabaseManager {

    Connection conn = null;

    public DatabaseManager() {
        String filename = "HomeAffairs.accdb";
        try {
            Class.forName("net.ucanaccess.jdbc.ucanaccessDriver");

            if (filename.endsWith(".mdb") || filename.endsWith(".accdb")) {
                String url = "jdbc:ucanaccess://" + filename;
                conn = DriverManager.getConnection(url); 
            } else {
                throw new FileNotFoundException();
            }
            System.out.println("Connection successful");
        } catch (Exception e) {
            System.out.println("Failed to get connection");
            e.printstacktrace();
        }
    }

    //Querys the database
    public ResultSet queryDatabase(String sql) throws sqlException {
        Statement stmt = conn.createStatement();
        return stmt.executeQuery(sql);
    }

    //Updates the tables in the database
    public void updateDatabase(String sql) throws sqlException {
        Statement stmt = conn.createStatement();
        stmt.execute(sql);
    }
}

如果您能帮助我，我将不胜感激！

这是我收到的错误：

线程“ AWT-EventQueue-0”中的异常java.lang.NullPointerException 在HomeAffairsPackage.ApplicantManager。（ApplicantManager.java:26）在HomeAffairsPackage.LoginScreen.LoginButtonActionPerformed（LoginScreen.java:177）在HomeAffairsPackage.LoginScreen $ 7.actionPerformed（LoginScreen.java:143）在java.desktop / javax.swing.AbstractButton.fireActionPerformed（AbstractButton.java:1967）在java.desktop / javax.swing.AbstractButton $ Handler.actionPerformed（AbstractButton.java:2308）在java.desktop / javax.swing.DefaultButtonModel.fireActionPerformed（DefaultButtonModel.java:405）在java.desktop / javax.swing.DefaultButtonModel.setpressed（DefaultButtonModel.java:262）在java.desktop / javax.swing.plaf.basic.BasicButtonListener.mouseReleased（BasicButtonListener.java:279）在java.desktop / java.awt.Component.processMouseEvent（Component.java:6636）在java.desktop / javax.swing.JComponent.processMouseEvent（JComponent.java:3342）在java.desktop / java.awt.Component.processEvent（Component.java:6401）在java.desktop / java.awt.Container.processEvent（Container.java:2263）在java.desktop / java.awt.Component.dispatchEventImpl（Component.java:5012）在java.desktop / java.awt.Container.dispatchEventImpl（Container.java:2321）在java.desktop / java.awt.Component.dispatchEvent（Component.java:4844）在java.desktop / java.awt.Lightweightdispatcher.retargetMouseEvent（Container.java:4919）在java.desktop / java.awt.Lightweightdispatcher.processMouseEvent（Container.java:4548）在java.desktop / java.awt.Lightweightdispatcher.dispatchEvent（Container.java:4489）在java.desktop / java.awt.Container.dispatchEventImpl（Container.java:2307）在java.desktop / java.awt.Window.dispatchEventImpl（Window.java:2764）在java.desktop / java.awt.Component.dispatchEvent（Component.java:4844）在java.desktop / java.awt.EventQueue.dispatchEventImpl（EventQueue.java:772）在java.desktop / java.awt.EventQueue $ 4.run（EventQueue.java:721）在java.desktop / java.awt.EventQueue $ 4.run（EventQueue.java:715）在java.base / java.security.AccessController.doPrivileged（AccessController.java:391）在java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:85）在java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:95）在java.desktop / java.awt.EventQueue $ 5.run（EventQueue.java:745）在java.desktop / java.awt.EventQueue $ 5.run（EventQueue.java:743）在java.base / java.security.AccessController.doPrivileged（AccessController.java:391）在java.base / java.security.ProtectionDomain $ JavaSecurityAccessImpl.doIntersectionPrivilege（ProtectionDomain.java:85）在java.desktop / java.awt.EventQueue.dispatchEvent（EventQueue.java:742）在java.desktop / java.awt.EventdispatchThread.pumpOneEventForFilters（EventdispatchThread.java:203）在java.desktop / java.awt.EventdispatchThread.pumpEventsForFilter（EventdispatchThread.java:124）在java.desktop / java.awt.EventdispatchThread.pumpEventsForHierarchy（EventdispatchThread.java:113）在java.desktop / java.awt.EventdispatchThread.pumpEvents（EventdispatchThread.java:109）在java.desktop / java.awt.EventdispatchThread.pumpEvents（EventdispatchThread.java:101）在java.desktop / java.awt.EventdispatchThread.run（EventdispatchThread.java:90）