Неизвестное исключение в netbeans java при подключении базы данных оракула

Question

Я следую за шаблоном MVC в java netbeans для некоторого проекта. Я пытаюсь подключить базу данных к моему приложению и запустить простой запрос показать все данные в JTable. Я закодирован отлично, но когда я запускаю свой проект он выдает ошибку:

package com.innovatraasolutions.eev.dal; 

import com.innovatraasolutions.eev.bo.Voters; 
import java.io.BufferedReader; 
import java.io.FileNotFoundException; 
import java.io.FileReader; 
import java.io.IOException; 
import java.util.ArrayList; 
import java.util.List; 
import java.util.logging.Level; 
import java.util.logging.Logger; 
import java.sql.*; 
/** 
* 
* @author SuperMan 
*/ 
public class VoterDAO { 

    /** 
    * 
    * @param voter 
    * @return 
    */ 
    public List<Voters> verifyVoter(Voters voter){ 
     String filename = null; 
     FileReader userFileReader = null; 
     FileReader userFileReader2 = null; 
     Connection connection = null; 

     List<Voters> list = new ArrayList<Voters>(); 

     try{ 
      String driverName = "oracle.jdbc.driver.OracleDriver"; 
      Class.forName(driverName); 
      String serverName = "SpiderMan"; 
      String serverPort = "1521"; 
      String sid = "XE"; 
      String url = "jdbc|oracle|thin|@" + serverName + "|" + serverPort + "|"; 
      String userName = "eev"; 
      String password = "123"; 

      connection = DriverManager.getConnection(url, userName, password); 

      System.out.println("Sucessfully connected to the DataBase"); 
     } catch(ClassNotFoundException e){ 
      System.out.println("Class Not Found Exeption::Couldn't find the database driver" + e.getMessage()); 
     } catch(SQLException e) { 
      System.out.println("Couldn't connect to the database" + e.getMessage()); 
     } 

     /*---------------------------------------------------*/ 
     //for retrieving data from database 
     try{ 
      Statement statement = connection.createStatement(); 
      ResultSet resultSet = statement.executeQuery("select *from Voter"); 

      while(resultSet.next()){ 
       String vcnic = resultSet.getString(1); 
       voter.setCnic(vcnic); 

       String Fname = resultSet.getString(2).toString(); 
       voter.setFname(Fname); 

       String Lname = resultSet.getString(3).toString(); 
       voter.setLname(Lname); 

       String VoteRegisteredIn = resultSet.getString(4).toString(); 
       voter.setVoteRegistered(VoteRegisteredIn); 

       String Address = resultSet.getString(5).toString(); 
       voter.setAddress(Address); 

       list.add(voter); 
      } 
      resultSet.close(); 

     }catch(Exception e){ 
      e.printStackTrace(); 
     } 
     return list; 

    /* try{ 
      userFileReader = new FileReader("voters.txt"); 
      String line = "a"; 
      BufferedReader voterFileBuffReader = new BufferedReader(userFileReader); 

      while((line = voterFileBuffReader.readLine()) != null){ 
       // System.out.println("Yesss"); 
       //filename = line + ".txt"; 
       //System.out.println(filename); 
       //System.out.println("first While"); 

       userFileReader2 = new FileReader("voters.txt"); 
       BufferedReader studFileBuffReader = new BufferedReader(userFileReader2); 

       while((line = studFileBuffReader.readLine()) != null){ 
        //System.out.println("Second While"); 
        String Cnic = line; 
        voter.setCnic(Cnic); 

        String Fname = studFileBuffReader.readLine(); 
        voter.setFname(Fname); 

        String Lname = studFileBuffReader.readLine(); 
        voter.setLname(Lname); 

        String VoteRegistered = studFileBuffReader.readLine(); 
        voter.setVoteRegistered(VoteRegistered); 

        String Address = studFileBuffReader.readLine(); 
        voter.setAddress(Address); 

        list.add(voter); 


     } 

    } 

    }*/ 
     /* catch(Exception e){ 
      System.err.println("Exception::"); 
     } */ 

} 

} 

И это дает следующее сообщение об ошибке: это

run: 
File not found! 
Couldn't connect to the databaseNo suitable driver found for jdbc|oracle|thin|@SpiderMan|1521| 
java.lang.NullPointerException 
    at com.innovatraasolutions.eev.dal.VoterDAO.verifyVoter(VoterDAO.java:58) 
    at com.innovatraasolutions.eev.bl.VoterHandler.verifyVoter(VoterHandler.java:27) 
    at com.innovatraasolutions.eev.controller.Controller.verifyVoter(Controller.java:83) 
    at com.innovatraasolutions.eev.controller.Controller.processRequest(Controller.java:43) 
    at com.innovatraasolutions.eev.ui.Voter.viewVoterActionPerformed(Voter.java:125) 
    at com.innovatraasolutions.eev.ui.Voter.access$000(Voter.java:21) 
    at com.innovatraasolutions.eev.ui.Voter$2.actionPerformed(Voter.java:75) 
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022) 
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346) 
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402) 
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259) 
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252) 
    at java.awt.Component.processMouseEvent(Component.java:6525) 
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3321) 
    at java.awt.Component.processEvent(Component.java:6290) 
    at java.awt.Container.processEvent(Container.java:2234) 
    at java.awt.Component.dispatchEventImpl(Component.java:4881) 
    at java.awt.Container.dispatchEventImpl(Container.java:2292) 
    at java.awt.Component.dispatchEvent(Component.java:4703) 
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898) 
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533) 
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462) 
    at java.awt.Container.dispatchEventImpl(Container.java:2278) 
    at java.awt.Window.dispatchEventImpl(Window.java:2739) 
    at java.awt.Component.dispatchEvent(Component.java:4703) 
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:746) 
    at java.awt.EventQueue.access$400(EventQueue.java:97) 
    at java.awt.EventQueue$3.run(EventQueue.java:697) 
    at java.awt.EventQueue$3.run(EventQueue.java:691) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) 
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86) 
    at java.awt.EventQueue$4.run(EventQueue.java:719) 
    at java.awt.EventQueue$4.run(EventQueue.java:717) 
    at java.security.AccessController.doPrivileged(Native Method) 
    at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75) 
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:716) 
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) 
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) 
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) 
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) 
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) 
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82) 
BUILD SUCCESSFUL (total time: 31 seconds) 

Answer 1

Проверьте драйвер оракула .jar файл прилагается к вашему проекту. проверить эту ссылку [https://www.youtube.com/watch?v=jsS_cRbNv3o]

Answer 2

Вам не удалось создать соединение, следовательно, вы видите следующее в журнале «Не удалось подключиться к базе данныхНет подходящего драйвера для jdbc | oracle | thin | @SpiderMan | 1521 |»

Вы должны изменить следующую строку из:

String url = "jdbc|oracle|thin|@" + serverName + "|" + serverPort + "|"; 

Для

String url = "jdbc:oracle:thin:@" + serverName + ":" + serverPort + "/" + sid; 

, если вы знаете имя базы данных вы можете добавить его быть похожим:

String url = "jdbc:oracle:thin:@" + serverName + ":" + serverPort + ":" + dbname;