我正在尝试获取某人用于登录的用户名，然后在某人发出提示时将其插入数据库
这是“programaritest”表

ID_programare | Nume | Prenume | Data | Ora | Departament | Doctor | Username | Nr_telefon

这是accounts表，其中用户名保存为unique

ID_account | Username | Password | Email | Nume |  Prenume | Admin

用户名的输入是通过一个textfield从fxml获得的，在getusername方法中，我在下面指出了这一点

package LicentaApp;

public class LogareController implements Initializable {
 public LoginVerifier loginVerifier = new LoginVerifier();

   @FXML
   private TextField Numeutilzator; Numeutilziator is the username that I am talking about

   @FXML
   private PasswordField Parola;

   @FXML
   private Label Stare;

 @Override
 public void initialize(URL location, ResourceBundle resources) {

  if (loginVerifier.Conexiune()) {
      Stare.setText("");
  } else {

      Stare.setText("Conexiune nereusita!");

  }

 }

 public void Autentificare (ActionEvent event) {
 try {
         if(loginVerifier.testaredate(Numeutilzator.getText(),     Parola.getText())) {
         Stare.setText("Autentificare reusita !");
         ((Node)event.getSource()).getScene().getWindow().hide();
            Stage StagePrincipala= new Stage();
            FXMLLoader incarcator= new FXMLLoader();
            Pane parinte = incarcator.load(getClass().getResource("/LicentaApp/Meniu.fxml").openStream());

            Scene scene = new Scene(parinte);
                scene.getStylesheets().add(getClass().getResource("Style1212.css").toExternalForm());
            StagePrincipala.setScene(scene);
            StagePrincipala.show();

          }
     else { 
         Stare.setText("Nume de utilizator sau parola incorect");

     }

} catch (SQLException e) {

     e.printStackTrace();
} catch (IOException e) {

    e.printStackTrace();
    }
 }
 @FXML
    public void Inregistrare(ActionEvent event) {
        try {
         ((Node)event.getSource()).getScene().getWindow().hide();
            Stage PS= new Stage();
            FXMLLoader incarcator= new FXMLLoader();
            Pane parinte = incarcator.load(getClass().getResource("/LicentaApp/InregistrareUser.fxml").openStream());
            Scene scena = new Scene(parinte);
            scena.getStylesheets().add(getClass().getResource("Style1212.css").toExternalForm());
            PS.setScene(scena);
            PS.show();
    } catch (Exception e) {

    }

* Here I m calling the function that I made in AddProgramareController and

passing it the username located in Numeutilzator*

@FXML 
 public void GetUsername() {
     try {
     FXMLLoader loader=new     FXMLLoader(getClass().getResource("/LicentaApp/AddProgramare.fxml"));
     Parent root = (Parent) loader.load();

     AddProgramareController AddPr=loader.getController();
     AddPr.MyUsername(Numeutilzator.getText());

 } catch (IOException e) {
     e.printStackTrace();
 }
 }

}
}

下面是一个将apointment添加到db的类，我在下面的代码中指出了用户名的函数是什么（我添加了所有代码，以便您更好地理解发生了什么）

package LicentaApp;

public class AddProgramareController implements Initializable {
    ObservableList Timestamp=FXCollections.observableArrayList();

@FXML
private TextField Nume;

@FXML
private TextField Prenume;

@FXML
private TextField Ora;

@FXML
private DatePicker Data;

@FXML
private TextField Departament;

@FXML
private TextField Doctor;

@FXML
private TextField Nr_telefon;

@FXML
private TextField Numeutilizator;

public void initialize(URL location, ResourceBundle resources) {

} 

* This is the function that I'll call in GetUsername from LogareController

 public void MyUsername(String Numeutilizator) {
    this.Numeutilizator.setText(Numeutilizator);

}

@FXML 
private void AddProgramare(ActionEvent event) throws SQLException, IOException  {

    String Interogare1= "INSERT INTO programaritest(Nume,Prenume,Data,Ora,Departament,Doctor,Nr_telefon,Numeutilizator) VALUES(?,?,?,?,?,?,?,?)";

    String nume=Nume.getText();
    String prenume=Prenume.getText();

    LocalDate data=Data.getValue(); 

    String ora=Ora.getText();
    String departament=Departament.getText();
    String doctor=Doctor.getText();
    String nr_telefon=Nr_telefon.getText();
    String numeutilizator=Numeutilizator.getText();

    try {
        ConectaredB ConectaredB=new ConectaredB();
        Connection conexiune=ConectaredB.logareDB();
        PreparedStatement MG = conexiune.prepareStatement(Interogare1);

        MG.setString(1, nume);
        MG.setString(2, prenume);
        MG.setDate(3, Date.valueOf(data)); 
        MG.setString(4, ora);
        MG.setString(5, departament);
        MG.setString(6, doctor);
        MG.setString(7, nr_telefon);
        MG.setString(8, numeutilizator);

        MG.executeUpdate();

        // ...
   } catch (SQLException exceptie1) {
       exceptie1.printStackTrace(); 
   }

}
}

尝试添加新约会时收到的错误消息是：
由以下原因引起：java.lang.nullpointerexception at licenstapp.addprogramarecontroller.addprogramare（addprogramarecontroller）。java:103)
在第103行：string numeutilizator=numeutilizator.gettext（）；
所以来自numeutilizator的数据不是输入输出的数据，这意味着我无法将参数从一个控制器传递到另一个控制器。
p、 我跟踪了这个传递参数javafx-fxml，搞不懂。