SedJ601's questions

我已经用了try-with-resources很多次了。我File经常用它来关闭数据库资源类型或其他东西。

现在，我正在使用 POI 处理大型 Excel 文件，我刚刚注意到我应该调用workbook.dispose()。try-with-resources 会调用该dispose()方法吗？我查找的所有内容仅涵盖close()。

我不确定重复的问题是否是同一个问题。我的问题具体询问是否Dispose由 处理try-with-resource。其他问题均未提及Dispose。

我创建了一个应用程序来回答问题。在大多数情况下，该应用程序运行正常，但我从ScheduledService updateMessage. 我的理解udpateMessage可能是错误的，这可能会让我误入歧途。我的理解是每次调用时都updateMessage应该更新。在本例中，应该每三秒一次。在这个应用程序中，这种情况没有发生。并且都按预期进行更新。这是错误的行为，还是我对工作原理的想法错误？messagePropertyupdateMessageupdateValueSystem.out.printlnupdateMessage

主要的

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.concurrent.ScheduledService;
import javafx.concurrent.Task;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.util.Duration;
import org.controlsfx.control.Notifications;

public class App extends Application {
    
    static List<MyNotification> myNotifications = new ArrayList();
    static FakeDatabaseHandler fakeDatabaseHandler = new FakeDatabaseHandler();
    
    @Override
    public void start(Stage stage) {
        
        Button btnGenerateNotification = new Button("Generate!");
        btnGenerateNotification.setOnAction(actionEvent ->{            
             fakeDatabaseHandler.addFakeNotificationsToDb();
        });

        Label lblUpdateMessage = new Label("Update Message: ");
        
        ScheduledService<List<MyNotification>> checkForScheduledService = new CheckForNotificationsScheduledService();
        checkForScheduledService.setPeriod(Duration.seconds(5));
        checkForScheduledService.messageProperty().addListener((ov, oldValue, newValue) -> {
            if(newValue != null)
            {
                lblUpdateMessage.setText("Update Message: " + newValue);
            }
        });
        
        checkForScheduledService.valueProperty().addListener((ov, oldValue, newValue) -> {
            if(newValue != null && !newValue.isEmpty())
            {
                myNotifications.clear();
                myNotifications.addAll(newValue);
                checkForScheduledService.cancel();
                
                AtomicInteger index = new AtomicInteger(0);
                checkForScheduledService.cancel();
                Timeline threeSecondsWonder = new Timeline(
                    new KeyFrame(Duration.seconds(3),  event -> {    
                        MyNotification myNotification = myNotifications.get(index.getAndIncrement());
                        Notifications.create().title(myNotification.department()+ " - " + myNotification.title()).text(myNotification.message()).hideAfter(Duration.seconds(3)).showWarning();
                    })
                );
                threeSecondsWonder.setCycleCount(myNotifications.size());
                threeSecondsWonder.play();
                threeSecondsWonder.setOnFinished((t) -> {
                    checkForScheduledService.restart();
                });
            }
        });
        checkForScheduledService.start();
        
        StackPane root = new StackPane(new VBox(btnGenerateNotification, lblUpdateMessage));

        stage.setScene(new Scene(root, 500, 500));
        stage.setTitle("Facilities");
        stage.show();        
    }

    public static void main(String[] args) {
        launch(args);
    }
    
    private static class CheckForNotificationsScheduledService extends ScheduledService<List<MyNotification>> {

    @Override
    protected Task<List<MyNotification>> createTask() {
        return new Task<List<MyNotification>>() {
            @Override
            protected List<MyNotification> call() throws Exception {
                List<MyNotification> fakeNotificationList = fakeDatabaseHandler.getFakeNotificationsFromDB();
                
                System.out.println("Checking for notifications. Notifications Found: " + fakeNotificationList.size());
                updateMessage("Checking for notifications. Notifications Found: " + fakeNotificationList.size());             
                updateValue(fakeNotificationList);                
                
                return fakeNotificationList; 
            }
        };
    }
  }
}

假数据库处理程序

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

/**
 *
 * @author Sed
 */
public class FakeDatabaseHandler {
    private final List<MyNotification> fakeDBData = new ArrayList();    
    
    public FakeDatabaseHandler() {}
    
    public void addFakeNotificationsToDb(){
        List<String> departmentList = Arrays.asList("A", "B", "C", "D");
              
        for(int i = 0; i < ThreadLocalRandom.current().nextInt(1, 6); i++)
        {
            int notificationID = ThreadLocalRandom.current().nextInt( 1000000);
            fakeDBData.add(new MyNotification("Department: " + departmentList.get(ThreadLocalRandom.current().nextInt(4)), "Title " + notificationID, "Message: " + notificationID));
        }
    }
    
    public List<MyNotification> getFakeNotificationsFromDB(){
        List<MyNotification> returnList = new ArrayList(fakeDBData);
        fakeDBData.clear();
        
        return returnList;
    }
}

我的通知

public record MyNotification(String department, String title, String message) {}

模块信息

module com.mycompany.javafxsimpletest {  
    requires org.controlsfx.controls;
    exports com.mycompany.javafxsimpletest;
}

输出

技术信息

Product Version: Apache NetBeans IDE 18
Java: 19.0.2; OpenJDK 64-Bit Server VM 19.0.2+7-jvmci-22.3-b12
Runtime: OpenJDK Runtime Environment 19.0.2+7-jvmci-22.3-b12
System: Windows 11 version 10.0 running on amd64; UTF-8; en_US (nb)