每次我尝试输入电子邮件密码的详细信息并命名该名称时，按钮上都会出现空指针异常。

但是，数据库上的所有内容也都有效，并且连接也已建立，但是在按下添加会计按钮后出现错误。

我试图检查数据库连接代码是否一切正常，并且连接变量也已初始化。

private void addbtn2actionPerformed(java.awt.event.actionEvent evt) {                                        

    try {


        PreparedStatement stmt = con.prepareStatement("INSERT INTO accountant('email','password','name')VALUES(?,?,?)");

        String names=namef2.getText();
        String emails=emailf2.getText();
        String passwords=String.valueOf(jPasswordField2.getText());
        String c_p=String.valueOf(jPasswordField2.getText());
        stmt.setString(1,emails);
        stmt.setString(2,passwords);
        stmt.setString(3,names);
        JOptionPane.showmessagedialog(null,"accountant Successfully added");
        stmt.execute();
        stmt.close();

    } catch (SQLException ex) {
        Logger.getLogger(accountantDetails.class.getName()).log(Level.SEVERE,null,ex);
    }
}    

输出

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at Admin.panel.accountantDetails.addbtn2actionPerformed(accountantDetails.java:300)
at Admin.panel.accountantDetails.access$300(accountantDetails.java:15)
at Admin.panel.accountantDetails$4.actionPerformed(accountantDetails.java:186)
at javax.swing.AbstractButton.fireactionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
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:6539)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
at java.awt.Component.processEvent(Component.java:6304)
at java.awt.Container.processEvent(Container.java:2239)
at java.awt.Component.dispatchEventImpl(Component.java:4889)
at java.awt.Container.dispatchEventImpl(Container.java:2297)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4904)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4535)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4476)
at java.awt.Container.dispatchEventImpl(Container.java:2283)
at java.awt.Window.dispatchEventImpl(Window.java:2746)
at java.awt.Component.dispatchEvent(Component.java:4711)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:709)
at java.awt.EventQueue$3.run(EventQueue.java:703)
at java.security.accessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityaccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.security.ProtectionDomain$JavaSecurityaccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
at java.awt.EventQueue$4.run(EventQueue.java:733)
at java.awt.EventQueue$4.run(EventQueue.java:731)
at java.security.accessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityaccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
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: 11 seconds)