Java Hibernate在插入用户名和密码时获取实体ID并将其删除

Question

我想获取已插入实体的自动生成的 ID 到 MySQL，我有一个使用 javafx 和 hibernate 制作的应用程序，我不能删除实体，因为 ID 是自动生成的，我必须获取实体的 ID ，所以在我将它保存到数据库之后，然后写入用户名和密码，我希望它给我插入的用户名和密码的 ID。假设我已经插入了实体用户名:1​​23，密码:asd，它会自动生成 ID : 1. 现在，如果我在字段中写入用户名:1​​23，密码:asd 并单击删除按钮，它应该删除该实体..但它没有...所以我需要获取它的 ID 并按 ID 删除它我不知道怎么做。

public class TestMain extends Application { 
     static Employee m = new Employee();

    public static void main(String[] args)  {  launch(args);   }  

        @Override
        public void start(Stage primaryStage) throws Exception {
            // TODO Auto-generated method stub

                Stage window = primaryStage;

                window.setTitle("WELCOME");

                Label l1 = new Label();
                // l1.setFont(new Font(48));
                l1.setText("SMS");
                l1.setTranslateY(-180);                            

                Button closeBut = new Button("Exit.");
                closeBut.setTooltip(new Tooltip("Click to exit application"));
                closeBut.setOnAction(e -> window.close());
                Button save = new Button ("Save");
                save.setTooltip(new Tooltip("Click to save to database"));


                Label l2 = new Label("Username ");
                TextField username = new TextField();
                username.setTooltip(new Tooltip("Enter your new username"));
                username.setPromptText("username");
                GridPane.setConstraints(l2,0,0);
                GridPane.setConstraints(username,1,0);

                Label l3 = new Label("Password ");
                PasswordField password = new PasswordField();
                password.setTooltip(new Tooltip("Enter your new password"));
                password.setPromptText("password");
                GridPane.setConstraints(l3,0,1);
                GridPane.setConstraints(password,1,1);

                Label l4 = new Label();
                GridPane.setConstraints(l4,0,4);
                GridPane.setConstraints(save,0,2);
                GridPane.setConstraints(closeBut,1,2);              

                //Configureation Hibernate
               // Configuration config = new Configuration();
                //config.configure("hibernate.cfg.xml");

                   SessionFactory sf = new Configuration().configure().buildSessionFactory();

                 //  
                       save.setOnAction(e -> {
                       m.setUser(username.getText());
                       m.setPassword(password.getText());   

                       Session session = sf.openSession();   
                       session.beginTransaction();                                                                                       
                       session.delete(m);                      
                       session.getTransaction().commit();

                });

                GridPane grid = new GridPane();
                grid.setPadding(new Insets(10,10,10,10));
                grid.setVgap(8);
                grid.setHgap(0);

                grid.getChildren().addAll(l1,l2,username,l3,password,save,l4,closeBut);
                grid.setAlignment(Pos.CENTER);
                Scene scene = new Scene(grid,300,400);
                window.setScene(scene);
                window.show();

   }
}               

Java 类员工:

package mypackage;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.*;
import javax.persistence.Id;

@Entity(name="EMPLOYEE")
public class Employee {

    @Id @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="ID")
    private int Id;


    @Column(name="USERNAME")
    private String user;

    @Column(name="PASSWORD")
    private String password;


    public int getId() {
        return Id;
    }

    public void setId(int Id) {
        this.Id = Id;
    }

    public String getUser() {
        return user;
    }

    public void setUser(String user) {
        this.user = user;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
    }

Answer 1

如您所说，我会选择一个单独的按钮，而不是混合使用。

因此您的保存操作将是:

save.setOnAction(e -> {
   m.setUser(username.getText());
   m.setPassword(password.getText());   

   Session session = sf.openSession();   
   session.beginTransaction();                                                                                       
   session.save(m);                      
   session.getTransaction().commit();

您的删除操作将是:

delete.setOnAction(e -> {
   Session session = sf.openSession();   
   Transaction tx;

   try{
     tx = session.beginTransaction();

       Query query = session.createQuery("from Employee where user = :user and password = :password");
     query.setString("user", username.getText());
     query.setString("password", password.getText());

     Employee userToDelete = (Employee)query.uniqueResult();  

     session.delete(userToDelete );                      
     tx.commit(); 
   }catch(Exception e){
       tx.rollback();
   }finally{
        session.close();
   }