JavaFX 场景构建器在启动程序上显示变量

Question

您好，我尝试在 JavaFX 的 start 方法中从 MySQL 执行 getData 之类的操作

现在在 Intellji 中，我单击“运行程序”，然后屏幕上会出现窗口。

我有一个“获取数据”按钮，点击它后，我从 Mysql 获取数据以在标签中显示。

当我们点击“运行程序”时，我们的程序的JavaFX显示窗口和这个来自MySQL的数据会自动显示在标签中是一些解决方案？

我的意思是如何在 public void start 中运行方法 getData(从 MySQL 获取数据)？

我显示变量“Label labelek;”点击按钮后 “标签标签；”在getData方法中

public class Main extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception{
        Parent root = FXMLLoader.load(getClass().getResource("sample.fxml"));
        primaryStage.setTitle("Hello World");
        primaryStage.setScene(new Scene(root, 600, 275));

        DBConnect connect = new DBConnect();    
        primaryStage.show();
    }    

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

数据库连接

package sample;    
import javafx.fxml.FXML;
import javafx.scene.control.Label;    
import java.sql.*;

public class DBConnect {

    private Connection con;
    private Statement st;
    private ResultSet rs;
    @FXML
    public Label labelek;

    //utworzenie konstruktora
    public DBConnect(){
        try {
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection("jdbc:mysql://xxx","xxx",
                    "xxx");
            st = con.createStatement();

        } catch (Exception ex){
            System.out.println("Error: " + ex);
        }
    }
    public void getData(){
        try {
            String query = "select * from x order by id desc limit 1";
            rs = st.executeQuery(query);
            System.out.println("Records from DataBase");
            while(rs.next()){                   
                String TemperaturaPow = rs.getString("TemperaturaPow");

         labelek.setText("Temperature is " + temperathure);

            }
        } catch (Exception ex){
            System.out.println("Error: " + ex);
        }
    }
 }

Answer 1

从DBConnect 类中删除Label labelek。创建单独的SampleController 类，在initalize() 方法中调用DBConnect connect = new DBConnect() 并将您的数据附加到Label labelek。

SampleController

public class SampleController implements Initializable {

    @FXML
    private Label labelek;
    @FXML
    private Button getDataButton;

    /**
     * Initializes the controller class.
     */
    @Override
    public void initialize(URL url, ResourceBundle rb) {
        // TODO
        DBConnect connect = new DBConnect(); 
        String data = connect.getData();
        labelek.setText(data);
    }
}

Answer 2

单击带有 onAction (SceneBuilder) getData 的按钮后，我只能在 IDEA 中看到 没有 TemperaturaPow 的“来自数据库的记录”：/

Scene Builder 中的控制器类是：sample.DBConnect

真的很难;P？

public String getData(){
    try {
        String query = "select * from danet order by id desc limit 1";
        rs = st.executeQuery(query);
        System.out.println("Records from DataBase");
        while(rs.next()){
            String DataCzas = rs.getString("dataczas");
            String TemperaturaPow = rs.getString("TemperaturaPow");
            String WilgotnoscPow = rs.getString("WilgotnoscPow");
            String Cisnienie = rs.getString("baro");
            String dewPoint = rs.getString("dewPoint");
            String heatIndexC = rs.getString("heatIndexc");
            String comment = rs.getString("comment");
            return TemperaturaPow;
        }
    } catch (Exception ex){
        System.out.println("Error: " + ex);
    }


    return null;
}

公共类 SampleController 实现 Initializable {

@FXML
private Label labelek;
@FXML
private Button getDataButton;

/**
 * Initializes the controller class.
 */
@Override
public void initialize(URL url, ResourceBundle rb) {
    // TODO
    DBConnect connect = new DBConnect();
    String data = connect.getData();
    labelek.setText(data);
}

PrintScreen