我有一个像这样的简单自定义日志记录框架:

package something;

import javafx.scene.control.TextArea;

public class MyLogger {
    public final TextArea textArea;

    private boolean verboseMode = false;
    private boolean debugMode = false;

    public MyLogger(final TextArea textArea) {
        this.textArea = textArea;
    }

    public MyLogger setVerboseMode(boolean value) {
        verboseMode = value;
        return this;
    }

    public MyLogger setDebugMode(boolean value) {
        debugMode = value;
        return this;
    }

    public boolean writeMessage(String msg) {
        textArea.appendText(msg);
        return true;
    }

    public boolean logMessage(String msg) {
        return writeMessage(msg + "\n");
    }

    public boolean logWarning(String msg) {
        return writeMessage("Warning: " + msg + "\n");
    }

    public boolean logError(String msg) {
        return writeMessage("Error: " + msg + "\n");
    }

    public boolean logVerbose(String msg) {
        return verboseMode ? writeMessage(msg + "\n") : true;
    }

    public boolean logDebug(String msg) {
        return debugMode ? writeMessage("[DEBUG] " + msg + "\n") : true;
    }
}

现在我想做的是扩展它，以便它能够通过线程正确处理消息记录。我尝试过类似 using message queues with an AnimationTimer 的解决方案.它可以工作，但会降低 GUI 的速度。

我还尝试使用 scheduled service它运行一个线程，从消息队列中读取消息，连接它们，并将它们附加到 TextArea (textArea.appendText(stringBuilder.toString()))。问题是 TextArea 控件变得不稳定，即您必须使用 Ctrl-A 突出显示所有文本并尝试调整窗口大小以使它们显示良好。还有一些以浅蓝色背景显示，不确定是什么原因造成的。我的第一个猜测是竞争条件可能不允许控件根据新字符串很好地更新自身。还值得注意的是，textarea 环绕在 ScrollPane 周围，因此如果 TextArea 实际上是有问题的那个或 ScrollPane，它会增加混淆。我还必须提到，这种方法不会使 TextArea 控件使用消息快速更新自身。

我考虑过将 binding TextArea.TextProperty() 到执行更新的东西，但我不确定如何在知道消息收集器的情况下正确地做到这一点(无论是通过服务还是单独的线程)仍将以不同于 GUI 线程的方式运行。

我尝试查找其他已知的日志记录框架解决方案，例如 log4j 和一些引用资料 here但它们似乎都没有给出通过线程记录到 TextArea 的明显方法。我也不喜欢在它们之上构建我的日志系统的想法，因为它们已经有它们的预定义机制，如日志级别等。

我看过 this以及。这意味着使用 SwingUtilities.invokeLater(Runnable) 来更新控件，但我已经尝试过使用 javafx.application.platform.runLater() 的类似方法，该方法在 worker 上执行线。我不确定我是否做错了什么，但它只是挂起。它可以产生消息，但当它们足够激进时就不会。我估计以纯同步方式运行的工作线程在 Debug模式下实际上每秒可以产生大约 20 行或更多行，甚至更多。一种可能的解决方法是也向其添加消息队列，但这不再有意义。

最佳答案

log-view.css

.root {
    -fx-padding: 10px;
}

.log-view .list-cell {
    -fx-background-color: null; // removes alternating list gray cells.
}

.log-view .list-cell:debug {
    -fx-text-fill: gray;
}

.log-view .list-cell:info {
    -fx-text-fill: green;
}

.log-view .list-cell:warn {
    -fx-text-fill: purple;
}

.log-view .list-cell:error {
    -fx-text-fill: red;
}

LogViewer.java

import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.binding.Bindings;
import javafx.beans.property.*;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.css.PseudoClass;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.Duration;

import java.text.SimpleDateFormat;
import java.util.Collection;
import java.util.Date;
import java.util.Random;
import java.util.concurrent.BlockingDeque;
import java.util.concurrent.LinkedBlockingDeque;

class Log {
    private static final int MAX_LOG_ENTRIES = 1_000_000;

    private final BlockingDeque<LogRecord> log = new LinkedBlockingDeque<>(MAX_LOG_ENTRIES);

    public void drainTo(Collection<? super LogRecord> collection) {
        log.drainTo(collection);
    }

    public void offer(LogRecord record) {
        log.offer(record);
    }
}

class Logger {
    private final Log log;
    private final String context;

    public Logger(Log log, String context) {
        this.log = log;
        this.context = context;
    }

    public void log(LogRecord record) {
        log.offer(record);
    }

    public void debug(String msg) {
        log(new LogRecord(Level.DEBUG, context, msg));
    }

    public void info(String msg) {
        log(new LogRecord(Level.INFO, context, msg));
    }

    public void warn(String msg) {
        log(new LogRecord(Level.WARN, context, msg));
    }

    public void error(String msg) {
        log(new LogRecord(Level.ERROR, context, msg));
    }

    public Log getLog() {
        return log;
    }
}

enum Level { DEBUG, INFO, WARN, ERROR }

class LogRecord {
    private Date   timestamp;
    private Level  level;
    private String context;
    private String message;

    public LogRecord(Level level, String context, String message) {
        this.timestamp = new Date();
        this.level     = level;
        this.context   = context;
        this.message   = message;
    }

    public Date getTimestamp() {
        return timestamp;
    }

    public Level getLevel() {
        return level;
    }

    public String getContext() {
        return context;
    }

    public String getMessage() {
        return message;
    }
}

class LogView extends ListView<LogRecord> {
    private static final int MAX_ENTRIES = 10_000;

    private final static PseudoClass debug = PseudoClass.getPseudoClass("debug");
    private final static PseudoClass info  = PseudoClass.getPseudoClass("info");
    private final static PseudoClass warn  = PseudoClass.getPseudoClass("warn");
    private final static PseudoClass error = PseudoClass.getPseudoClass("error");

    private final static SimpleDateFormat timestampFormatter = new SimpleDateFormat("HH:mm:ss.SSS");

    private final BooleanProperty       showTimestamp = new SimpleBooleanProperty(false);
    private final ObjectProperty<Level> filterLevel   = new SimpleObjectProperty<>(null);
    private final BooleanProperty       tail          = new SimpleBooleanProperty(false);
    private final BooleanProperty       paused        = new SimpleBooleanProperty(false);
    private final DoubleProperty        refreshRate   = new SimpleDoubleProperty(60);

    private final ObservableList<LogRecord> logItems = FXCollections.observableArrayList();

    public BooleanProperty showTimeStampProperty() {
        return showTimestamp;
    }

    public ObjectProperty<Level> filterLevelProperty() {
        return filterLevel;
    }

    public BooleanProperty tailProperty() {
        return tail;
    }

    public BooleanProperty pausedProperty() {
        return paused;
    }

    public DoubleProperty refreshRateProperty() {
        return refreshRate;
    }

    public LogView(Logger logger) {
        getStyleClass().add("log-view");

        Timeline logTransfer = new Timeline(
                new KeyFrame(
                        Duration.seconds(1),
                        event -> {
                            logger.getLog().drainTo(logItems);

                            if (logItems.size() > MAX_ENTRIES) {
                                logItems.remove(0, logItems.size() - MAX_ENTRIES);
                            }

                            if (tail.get()) {
                                scrollTo(logItems.size());
                            }
                        }
                )
        );
        logTransfer.setCycleCount(Timeline.INDEFINITE);
        logTransfer.rateProperty().bind(refreshRateProperty());

        this.pausedProperty().addListener((observable, oldValue, newValue) -> {
            if (newValue && logTransfer.getStatus() == Animation.Status.RUNNING) {
                logTransfer.pause();
            }

            if (!newValue && logTransfer.getStatus() == Animation.Status.PAUSED && getParent() != null) {
                logTransfer.play();
            }
        });

        this.parentProperty().addListener((observable, oldValue, newValue) -> {
            if (newValue == null) {
                logTransfer.pause();
            } else {
                if (!paused.get()) {
                    logTransfer.play();
                }
            }
        });

        filterLevel.addListener((observable, oldValue, newValue) -> {
            setItems(
                    new FilteredList<LogRecord>(
                            logItems,
                            logRecord ->
                                logRecord.getLevel().ordinal() >=
                                filterLevel.get().ordinal()
                    )
            );
        });
        filterLevel.set(Level.DEBUG);

        setCellFactory(param -> new ListCell<LogRecord>() {
            {
                showTimestamp.addListener(observable -> updateItem(this.getItem(), this.isEmpty()));
            }

            @Override
            protected void updateItem(LogRecord item, boolean empty) {
                super.updateItem(item, empty);

                pseudoClassStateChanged(debug, false);
                pseudoClassStateChanged(info, false);
                pseudoClassStateChanged(warn, false);
                pseudoClassStateChanged(error, false);

                if (item == null || empty) {
                    setText(null);
                    return;
                }

                String context =
                        (item.getContext() == null)
                                ? ""
                                : item.getContext() + " ";

                if (showTimestamp.get()) {
                    String timestamp =
                            (item.getTimestamp() == null)
                                    ? ""
                                    : timestampFormatter.format(item.getTimestamp()) + " ";
                    setText(timestamp + context + item.getMessage());
                } else {
                    setText(context + item.getMessage());
                }

                switch (item.getLevel()) {
                    case DEBUG:
                        pseudoClassStateChanged(debug, true);
                        break;

                    case INFO:
                        pseudoClassStateChanged(info, true);
                        break;

                    case WARN:
                        pseudoClassStateChanged(warn, true);
                        break;

                    case ERROR:
                        pseudoClassStateChanged(error, true);
                        break;
                }
            }
        });
    }
}

class Lorem {
    private static final String[] IPSUM = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Quisque hendrerit imperdiet mi quis convallis. Pellentesque fringilla imperdiet libero, quis hendrerit lacus mollis et. Maecenas porttitor id urna id mollis. Suspendisse potenti. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Cras lacus tellus, semper hendrerit arcu quis, auctor suscipit ipsum. Vestibulum venenatis ante et nulla commodo, ac ultricies purus fringilla. Aliquam lectus urna, commodo eu quam a, dapibus bibendum nisl. Aliquam blandit a nibh tincidunt aliquam. In tellus lorem, rhoncus eu magna id, ullamcorper dictum tellus. Curabitur luctus, justo a sodales gravida, purus sem iaculis est, eu ornare turpis urna vitae dolor. Nulla facilisi. Proin mattis dignissim diam, id pellentesque sem bibendum sed. Donec venenatis dolor neque, ut luctus odio elementum eget. Nunc sed orci ligula. Aliquam erat volutpat.".split(" ");
    private static final int MSG_WORDS = 8;
    private int idx = 0;

    private Random random = new Random(42);

    synchronized public String nextString() {
        int end = Math.min(idx + MSG_WORDS, IPSUM.length);

        StringBuilder result = new StringBuilder();
        for (int i = idx; i < end; i++) {
            result.append(IPSUM[i]).append(" ");
        }

        idx += MSG_WORDS;
        idx = idx % IPSUM.length;

        return result.toString();
    }

    synchronized public Level nextLevel() {
        double v = random.nextDouble();

        if (v < 0.8) {
            return Level.DEBUG;
        }

        if (v < 0.95) {
            return Level.INFO;
        }

        if (v < 0.985) {
            return Level.WARN;
        }

        return Level.ERROR;
    }

}

public class LogViewer extends Application {
    private final Random random = new Random(42);

    @Override
    public void start(Stage stage) throws Exception {
        Lorem  lorem  = new Lorem();
        Log    log    = new Log();
        Logger logger = new Logger(log, "main");

        logger.info("Hello");
        logger.warn("Don't pick up alien hitchhickers");

        for (int x = 0; x < 20; x++) {
            Thread generatorThread = new Thread(
                    () -> {
                        for (;;) {
                            logger.log(
                                    new LogRecord(
                                            lorem.nextLevel(),
                                            Thread.currentThread().getName(),
                                            lorem.nextString()
                                    )
                            );

                            try {
                                Thread.sleep(random.nextInt(1_000));
                            } catch (InterruptedException e) {
                                Thread.currentThread().interrupt();
                            }
                        }
                    },
                    "log-gen-" + x
            );
            generatorThread.setDaemon(true);
            generatorThread.start();
        }

        LogView logView = new LogView(logger);
        logView.setPrefWidth(400);

        ChoiceBox<Level> filterLevel = new ChoiceBox<>(
                FXCollections.observableArrayList(
                        Level.values()
                )
        );
        filterLevel.getSelectionModel().select(Level.DEBUG);
        logView.filterLevelProperty().bind(
                filterLevel.getSelectionModel().selectedItemProperty()
        );

        ToggleButton showTimestamp = new ToggleButton("Show Timestamp");
        logView.showTimeStampProperty().bind(showTimestamp.selectedProperty());

        ToggleButton tail = new ToggleButton("Tail");
        logView.tailProperty().bind(tail.selectedProperty());

        ToggleButton pause = new ToggleButton("Pause");
        logView.pausedProperty().bind(pause.selectedProperty());

        Slider rate = new Slider(0.1, 60, 60);
        logView.refreshRateProperty().bind(rate.valueProperty());
        Label rateLabel = new Label();
        rateLabel.textProperty().bind(Bindings.format("Update: %.2f fps", rate.valueProperty()));
        rateLabel.setStyle("-fx-font-family: monospace;");
        VBox rateLayout = new VBox(rate, rateLabel);
        rateLayout.setAlignment(Pos.CENTER);

        HBox controls = new HBox(
                10,
                filterLevel,
                showTimestamp,
                tail,
                pause,
                rateLayout
        );
        controls.setMinHeight(HBox.USE_PREF_SIZE);

        VBox layout = new VBox(
                10,
                controls,
                logView
        );
        VBox.setVgrow(logView, Priority.ALWAYS);

        Scene scene = new Scene(layout);
        scene.getStylesheets().add(
            this.getClass().getResource("log-view.css").toExternalForm()
        );
        stage.setScene(scene);
        stage.show();
    }

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

下面关于可选文本的部分是对上面发布的解决方案的补充。如果您不需要可选择的文本，您可以忽略下面的选择。

Is it possible to make the text selectable?

有几个不同的选项:

1. 它是一个 ListView，因此您可以使用 multiple selection model ，确保 CSS 配置为根据您的需要适当设置所选行的样式。这将逐行选择，而不是直接选择文本。您可以为选择模型中的选定项目添加一个监听器，并在发生变化时进行适当的处​​理。
2. 您可以为 ListView 使用一个工厂，它将每个单元格设置为适当样式的只读文本字段。这将允许某人只选择一行中的一部分文本而不是整行。但他们无法一次跨多行选择文本。

• Copiable Label/TextField/LabeledText in JavaFX

1. 而不是 ListView，您可以将实现基于第三方只读 RichTextFX控件，这将允许跨多行选择文本。

尝试实现适合您的文本选择方法，如果您不能让它工作，请创建一个特定于可选文本日志的新问题，使用 mcve .

关于java - 使用简单的自定义日志记录框架通过线程将消息记录到 JavaFX TextArea 的最有效方式，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/24116858/