JavaFx tableview排序非常慢，如何提高排序速度，就像在java swing中一樣

Question

我正在研究javaFx應用程序，並創建了一個tableview，大約有100,000多行，包含10列。

我還使用java swing Jtable創建了相同的表。

現在我需要排序性能在javaFx中更好，如果不比java swing的jtable更接近。

現在我使用sortorder（）通過單擊列標題對數據進行排序，排序速度比Jtable慢20倍。

有人可以幫忙嗎？

謝謝

編輯：

我在這個鏈接中使用示例13.8 http://docs.oracle.com/javafx/2/ui_controls/table-view.htm只添加了幾行代碼，通過生成隨機數據來添加100,000行。

Answer 1

花了一段時間，但我想我已經弄明白了，至少在這個例子中。

在此示例中，Person類沒有任何屬性訪問器（即，有一個getFirstName（）方法，但沒有firstNameProperty（）方法）。 按列排序必須通過單元格值工廠訪問列中每個單元格中的值。 當沒有屬性訪問器時，單元值工廠將調用getFirstName（），然后在每次調用時將結果包裝在新的ReadOnlyObjectWrapper中。

如果確保表示行數據的類具有適當的屬性訪問器，則檢索該值會更有效，因為它只返回對現有StringProperty的引用。

此示例在我的系統上大約一秒鍾內排序100,000行（MacBookPro 8GB RAM，四核）。 您可以通過提供顯式單元值工廠來提高性能，這可以滿足計算單元格值時反射的需要。 換句話說，替換

    firstNameCol.setCellValueFactory(
            new PropertyValueFactory<Person, String>("firstName"));

同

    firstNameCol.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<Person,String>, ObservableValue<String>>() {
      @Override
      public ObservableValue<String> call(CellDataFeatures<Person, String> cdf) {
        return cdf.getValue().firstNameProperty();
      }
    });

這里的性能節省並不那么引人注目。

這是完整的例子：

import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
import javafx.beans.value.ObservableValue;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.TableColumn.CellDataFeatures;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.text.Font;
import javafx.stage.Stage;
import javafx.util.Callback;

import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.Random;

public class TableSortPerformanceTest extends Application {


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

    @Override
    public void start(Stage stage) {
        Scene scene = new Scene(new Group());
        stage.setTitle("Table View Sample");
        stage.setWidth(550);
        stage.setHeight(550);

        final Label label = new Label("Address Book");
        label.setFont(new Font("Arial", 20));

        final TableView<Person> table = new TableView<Person>();
        table.setEditable(true);

        TableColumn<Person, String> firstNameCol = new TableColumn<Person, String>("First Name");
        firstNameCol.setMinWidth(100);
        firstNameCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("firstName"));
        firstNameCol.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<Person,String>, ObservableValue<String>>() {
          @Override
          public ObservableValue<String> call(CellDataFeatures<Person, String> cdf) {
            return cdf.getValue().firstNameProperty();
          }
        });

        TableColumn<Person, String> lastNameCol = new TableColumn<Person, String>("Last Name");
        lastNameCol.setMinWidth(100);
        lastNameCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("lastName"));



        TableColumn<Person, String> emailCol = new TableColumn<Person, String>("Email");
        emailCol.setMinWidth(200);
        emailCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("email"));


        Random random = new Random();
        for (int i = 0; i < 100000; i++) {
          table.getItems().add(new Person(randomString(random), randomString(random), randomString(random)));
        }
        table.getColumns().addAll(Arrays.asList(firstNameCol, lastNameCol, emailCol));

        long start = new Date().getTime();
        Collections.sort(table.getItems());
        long end   = new Date().getTime();
        System.out.println("Took: " + (end - start));


        final TextField addFirstName = new TextField();
        addFirstName.setPromptText("First Name");
        addFirstName.setMaxWidth(firstNameCol.getPrefWidth());
        final TextField addLastName = new TextField();
        addLastName.setMaxWidth(lastNameCol.getPrefWidth());
        addLastName.setPromptText("Last Name");
        final TextField addEmail = new TextField();
        addEmail.setMaxWidth(emailCol.getPrefWidth());
        addEmail.setPromptText("Email");

        final Button addButton = new Button("Add");
        addButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent e) {
                table.getItems().add(new Person(
                        addFirstName.getText(),
                        addLastName.getText(),
                        addEmail.getText()));
                addFirstName.clear();
                addLastName.clear();
                addEmail.clear();
            }
        });

        final HBox hb = new HBox(3);
        hb.getChildren().addAll(addFirstName, addLastName, addEmail, addButton);

        final VBox vbox = new VBox();
        vbox.setSpacing(5);
        vbox.setPadding(new Insets(10, 0, 0, 10));
        vbox.getChildren().addAll(label, table, hb);

        ((Group) scene.getRoot()).getChildren().addAll(vbox);

        stage.setScene(scene);
        stage.show();
    }

    private String randomString(Random random) {
      char[] chars = new char[20];
      for (int i = 0; i < 20; i++) {
        int nextInt = random.nextInt(26);
        nextInt += random.nextBoolean() ? 65 : 97;
        chars[i] = (char) nextInt;
      }
      return new String(chars);
    }

    public static class Person implements Comparable<Person> {

        private final StringProperty firstName;
        private final StringProperty lastName;
        private final StringProperty email;

        private Person(String fName, String lName, String email) {
            this.firstName = new SimpleStringProperty(fName);
            this.lastName = new SimpleStringProperty(lName);
            this.email = new SimpleStringProperty(email);
        }

        public String getFirstName() {
            return firstName.get();
        }

        public void setFirstName(String fName) {
            firstName.set(fName);
        }

        public StringProperty firstNameProperty() {
          return firstName ;
        }

        public String getLastName() {
            return lastName.get();
        }

        public void setLastName(String fName) {
            lastName.set(fName);
        }

        public StringProperty lastNameProperty() {
          return lastName ;
        }

        public String getEmail() {
            return email.get();
        }

        public void setEmail(String fName) {
            email.set(fName);
        }

        public StringProperty emailProperty() {
          return email ;
        }

    @Override
    public int compareTo(Person o) {
      return firstName.get().compareTo(o.getFirstName());
    }
  }
} 

更新：請注意，這已在JavaFX 8中修復。

Answer 2

當你點擊表格標題時，我不知道TableView上的排序速度是多少 - 如你在問題中提到的那樣，它變得很慢，有100,000行。

如果你只是提供一個對基礎集合進行排序的按鈕，它會更快地排序很多次並且表格更新（至少在Java 8下）。 對列進行排序的時間還不到一秒。

Button sortByEmail = new Button("Sort by Email");
sortByEmail.setOnAction(new EventHandler<ActionEvent>() {
  @Override public void handle(ActionEvent event) {
    Collections.sort(table.getItems(), new Comparator<Person>() 
      @Override public int compare(Person o1, Person o2) {
        return o1.getEmail().compareTo(o2.getEmail());
      }
    });
  }
});

或者使用Java 8 lambdas：

Button sortByEmail = new Button("Sort by Email");
sortByEmail.setOnAction(event -> 
    Collections.sort(
        table.getItems(), 
        (o1, o2) -> o1.getEmail().compareTo(o2.getEmail())
    )
);

因此，如果表中有很多項，則在列上調用setSortable（false），並為用戶提供按鈕，以便在需要時對表列進行排序。

將我的筆記本電腦插入牆壁並增加JVM的最大內存也增加了大型數據集的排序性能（通過單擊下面的樣本從20秒到大約10秒單擊列標題來縮短排序時間）。

使用以下示例代碼向JavaFX問題跟蹤器提交增強請求。 該代碼生成100,000行隨機數據，您可以通過單擊表列標題對表列進行排序來檢查標准列排序的性能，並將其與按按鈕調用的Collections.sort排序性能進行比較。

import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.text.Font;
import javafx.stage.Stage;

import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.Random;

public class Test extends Application {

    private TableView<Person> table = new TableView<Person>();
    private final ObservableList<Person> data =
            FXCollections.observableArrayList(
            new Person("Jacob", "Smith", "jacob.smith@example.com"),
            new Person("Isabella", "Johnson", "isabella.johnson@example.com"),
            new Person("Ethan", "Williams", "ethan.williams@example.com"),
            new Person("Emma", "Jones", "emma.jones@example.com"),
            new Person("Michael", "Brown", "michael.brown@example.com"));
    final HBox hb = new HBox();

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

    @Override
    public void start(Stage stage) {
        Scene scene = new Scene(new Group());
        stage.setTitle("Table View Sample");
        stage.setWidth(550);
        stage.setHeight(550);

        final Label label = new Label("Address Book");
        label.setFont(new Font("Arial", 20));

        table.setEditable(true);

        TableColumn firstNameCol = new TableColumn("First Name");
        firstNameCol.setMinWidth(100);
        firstNameCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("firstName"));

        TableColumn lastNameCol = new TableColumn("Last Name");
        lastNameCol.setMinWidth(100);
        lastNameCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("lastName"));

        TableColumn emailCol = new TableColumn("Email");
        emailCol.setMinWidth(200);
        emailCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("email"));

        Random random = new Random();
        table.setItems(data);
        for (int i = 0; i < 100000; i++) {
          table.getItems().add(new Person(randomString(random), randomString(random), randomString(random)));
        }
        table.getColumns().addAll(firstNameCol, lastNameCol, emailCol);

        long start = new Date().getTime();
        Collections.sort(table.getItems());
        long end   = new Date().getTime();
        System.out.println("Took: " + (end - start));


        final TextField addFirstName = new TextField();
        addFirstName.setPromptText("First Name");
        addFirstName.setMaxWidth(firstNameCol.getPrefWidth());
        final TextField addLastName = new TextField();
        addLastName.setMaxWidth(lastNameCol.getPrefWidth());
        addLastName.setPromptText("Last Name");
        final TextField addEmail = new TextField();
        addEmail.setMaxWidth(emailCol.getPrefWidth());
        addEmail.setPromptText("Email");

        final Button addButton = new Button("Add");
        addButton.setOnAction(new EventHandler<ActionEvent>() {
            @Override
            public void handle(ActionEvent e) {
                data.add(new Person(
                        addFirstName.getText(),
                        addLastName.getText(),
                        addEmail.getText()));
                addFirstName.clear();
                addLastName.clear();
                addEmail.clear();
            }
        });

        Button sortByFirstName = new Button("Sort by First Name");
        sortByFirstName.setOnAction(new EventHandler<ActionEvent>() {
          @Override
          public void handle(ActionEvent event) {
            Collections.sort(table.getItems());
          }
        });

        Button sortByEmail = new Button("Sort by Email");
        sortByEmail.setOnAction(new EventHandler<ActionEvent>() {
          @Override
          public void handle(ActionEvent event) {
            Collections.sort(table.getItems(), new Comparator<Person>() {
              @Override
              public int compare(Person o1, Person o2) {
                return o1.getEmail().compareTo(o2.getEmail());
              }
            });
          }
        });

        hb.getChildren().addAll(addFirstName, addLastName, addEmail, addButton, sortByFirstName, sortByEmail);
        hb.setSpacing(3);

        final VBox vbox = new VBox();
        vbox.setSpacing(5);
        vbox.setPadding(new Insets(10, 0, 0, 10));
        vbox.getChildren().addAll(label, table, hb);

        ((Group) scene.getRoot()).getChildren().addAll(vbox);

        stage.setScene(scene);
        stage.show();
    }

    private String randomString(Random random) {
      char[] chars = new char[20];
      for (int i = 0; i < 20; i++) {
        int nextInt = random.nextInt(26);
        nextInt += random.nextBoolean() ? 65 : 97;
        chars[i] = (char) nextInt;
      }
      return new String(chars);
    }

    public static class Person implements Comparable<Person> {

        private final SimpleStringProperty firstName;
        private final SimpleStringProperty lastName;
        private final SimpleStringProperty email;

        private Person(String fName, String lName, String email) {
            this.firstName = new SimpleStringProperty(fName);
            this.lastName = new SimpleStringProperty(lName);
            this.email = new SimpleStringProperty(email);
        }

        public String getFirstName() {
            return firstName.get();
        }

        public void setFirstName(String fName) {
            firstName.set(fName);
        }

        public String getLastName() {
            return lastName.get();
        }

        public void setLastName(String fName) {
            lastName.set(fName);
        }

        public String getEmail() {
            return email.get();
        }

        public void setEmail(String fName) {
            email.set(fName);
        }

    @Override
    public int compareTo(Person o) {
      return firstName.get().compareTo(o.getFirstName());
    }
  }
}