서버 연동은 했고
로그인 버튼을 누르면 이런 오류가 납니다!
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException: Cannot read field "db" because "this.this$0.o" is null
at Setting.MainFrame$ButtonListener.actionPerformed(MainFrame.java:680)
at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1972)
at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2313)
at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
at java.desktop/java.awt.Component.processMouseEvent(Component.java:6626)
at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3389)
at java.desktop/java.awt.Component.processEvent(Component.java:6391)
at java.desktop/java.awt.Container.processEvent(Container.java:2266)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5001)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2324)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4833)
at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4948)
at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4575)
at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4516)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2310)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2780)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4833)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:773)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:722)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:716)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:97)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:746)
at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:744)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:743)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
로그인 쪽 코드는
class ButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent e) { JButton b = (JButton)e.getSource(); /* TextField에 입력된 아이디와 비밀번호를 변수에 초기화 */ String uid = id.getText(); String upass = ""; for(int i=0; i<pw.getPassword().length; i++) { upass = upass + pw.getPassword()[i]; } /* 로그인 버튼 이벤트 */ if(b.getText().equals("로그인")) { if(uid.equals("") || upass.equals("")) { JOptionPane.showMessageDialog(null, "아이디와 비밀번호 모두 입력해주세요", "로그인 실패", JOptionPane.ERROR_MESSAGE); System.out.println("로그인 실패 > 로그인 정보 미입력"); } else if(uid != null && upass != null) { //여기서부터 오류 시작인듯 시발. if(o.db.logincheck(uid, upass)) { //이 부분이 데이터베이스에 접속해 로그인 정보를 확인하는 부분이다. System.out.println("로그인 성공"); JOptionPane.showMessageDialog(null, "로그인에 성공하였습니다"); } else { System.out.println("로그인 실패 > 로그인 정보 불일치"); JOptionPane.showMessageDialog(null, "로그인에 실패하였습니다"); } } } } }
// database 클래스
boolean logincheck(String _i, String _p) { boolean flag = false; String id = _i; String pw = _p; try { String checkingStr = "SELECT password FROM mainsh.member WHERE id='" + id + "'"; ResultSet result = stmt.executeQuery(checkingStr); int count = 0; while(result.next()) { if(pw.equals(result.getString("password"))) { flag = true; System.out.println("로그인 성공"); } else { flag = false; System.out.println("로그인 실패"); } count++; } } catch(Exception e) { flag = false; System.out.println("로그인 실패 > " + e.toString()); } return flag; }