监视log4j日志以查找Javafx

Question

我一般都是非常新的Java世界。我有一个javafx应用程序，我正在尝试在log4j日志文件上设置文件观察器以监视更改并显示textarea中的更改。我有以下代码，它可以在log4j日志文件以外的任何文件上正常工作。

另外，我注意到当我在Windows资源管理器中刷新包含log4j文件的文件夹时，它似乎工作。我很困惑，不知道我做错了什么或不确定这是否可行。

请告知。

package application;

import java.io.IOException;
import java.net.URL;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardWatchEventKinds;
import java.nio.file.WatchEvent;
import java.nio.file.WatchKey;
import java.nio.file.WatchService;
import java.util.ResourceBundle;
import java.util.stream.Collectors;

import org.apache.log4j.Logger;
import org.apache.log4j.PropertyConfigurator;

import javafx.application.Platform;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;
import javafx.scene.text.TextFlow;

public class MainappWindowController implements Initializable {

    @FXML
    private Button btn_appendtext;
    @FXML
    private TextArea txtarea_logview;
    @FXML
    private TextFlow txtflow_logview;

    // FOR Logging
    public static final Logger log = Logger.getLogger(Main.class);

    String log4jConfPath = "./log4j_properties/log4j.properties";

    Path watchPath = Paths.get("C:/temp/mylogfile_being_watched_by_java.txt");

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        // TODO Auto-generated method stub

        btn_appendtext.setOnAction(e -> {
            testlogger();
        });

        // load file initially
        if (Files.exists(watchPath)) {
            loadFile();
        } else {
            log.info("File does not exist");
        }

        // watch file
        WatchThread watchThread = new WatchThread(watchPath);
        watchThread.setDaemon(true);
        watchThread.start();

        // Add log4j properties file to configuration
        PropertyConfigurator.configure(log4jConfPath);

    }

    public void testlogger() {
        log.info("This is an information message");
    }

    private void loadFile() {
        try {
            String stringFromFile = Files.lines(watchPath).collect(Collectors.joining("\n"));
            txtarea_logview.setText(stringFromFile);

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    private class WatchThread extends Thread {
        Path watchPath;

        public WatchThread(Path watchPath) {
            this.watchPath = watchPath;
        }

        @Override
        public void run() {
            try {
                WatchService watcher = FileSystems.getDefault().newWatchService();
                WatchKey key = watchPath.getParent().register(watcher, StandardWatchEventKinds.ENTRY_CREATE,
                        StandardWatchEventKinds.ENTRY_MODIFY);

                while (true) {
                    // wait for key to be signaled
                    try {
                        key = watcher.take();
                    } catch (InterruptedException x) {
                        return;
                    }

                    for (WatchEvent<?> event : key.pollEvents()) {
                        WatchEvent.Kind<?> kind = event.kind();

                        if (kind == StandardWatchEventKinds.OVERFLOW) {
                            continue;
                        }

                        WatchEvent<Path> ev = (WatchEvent<Path>) event;
                        Path path = ev.context();
                        if (!path.getFileName().equals(watchPath.getFileName())) {
                            continue;
                        }
                        // process file
                        Platform.runLater(() -> {
                            loadFile();
                        });
                    }

                    boolean valid = key.reset();
                    if (!valid) {
                        break;
                    }
                }
            } catch (IOException x) {
                System.err.println(x);
            }
        }
    }
}