将log4j2输出附加到TextArea

Question

我正在log4j2中搜索一个简单的方法来将日志附加到textArea.

在log4j中,这可以通过扩展AppenderSkeleton类来实现,但我在log4j2中找不到类似的机制.

此外,使用重新路由系统输出

System.setOut(myPrintStream);

也不起作用.

是否有可能使用log4j2？

Answer 1

一个迟到的答案,但我终于找到了解决问题的方法.要将log4j2控制台流附加到JavaFX TextArea,ListView或类似控件甚至是摆动控制都是可能的.我的解决方案还将标准System.out附加到记录器视图.看你自己.

首先,我通过屏幕截图显示我当前的结果(抱歉,我不能直接在此处包含它,因为我在stackoverflow上的用户帐户信誉不足...): 查看屏幕截图

步骤1:编辑log4j2.xml文件并添加属性follow ="true":

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
<Appenders>
    <Console name="STDOUT" target="SYSTEM_OUT" follow="true">
        <PatternLayout pattern="%d %-5p (%F:%L) - %m%n" />
    </Console>
</Appenders>
<Loggers>
    <Root level="DEBUG">
        <AppenderRef ref="STDOUT" />
    </Root>
</Loggers>
</Configuration>

第2步:编写一个类,用于将SYSTEM_OUT附加到所需的可视控件

对于我的例子,我编写了一个小的UI控件组合,如截图所示.因此你需要一个fxml,一个fxml的控制器和一个LogStringCell,它提供颜色格式化(这不是必需的坚果噱头)

LoggerConsole.fxml

<?import java.lang.*?>
<?import javafx.scene.control.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>

<VBox prefHeight="200.0" prefWidth="800.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="tuc.plentyfx.configurator.views.LoggerConsoleController">
   <children>
      <ListView fx:id="listViewLog" />
      <ToolBar prefHeight="40.0" prefWidth="200.0">
        <items>
            <Button mnemonicParsing="false" onAction="#handleRemoveSelected" text="Selektierte löschen" />
            <Button fx:id="buttonClearLog" mnemonicParsing="false" onAction="#handleClearLog" text="Leeren" />
            <ToggleButton fx:id="toggleButtonAutoScroll" mnemonicParsing="false" text="Auto-Scroll" />
            <ChoiceBox fx:id="choiceBoxLogLevel" prefWidth="150.0" />
        </items>
      </ToolBar>
   </children>
</VBox>

控制器类LoggerConsoleController.java

package tuc.plentyfx.configurator.views;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PipedInputStream;
import java.io.PipedOutputStream;
import java.io.PrintStream;

import javafx.application.Platform;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import javafx.concurrent.Task;
import javafx.fxml.FXML;
import javafx.scene.control.ChoiceBox;
import javafx.scene.control.ListCell;
import javafx.scene.control.ListView;
import javafx.scene.control.SelectionMode;
import javafx.scene.control.ToggleButton;
import javafx.util.Callback;

import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.LoggerConfig;

import tuc.plentyfx.common.LogStringCell;

public class LoggerConsoleController {
    static final Logger logger = LogManager.getLogger(LoggerConsoleController.class.getName());

    @FXML
    private ListView<String> listViewLog;

    @FXML
    private ToggleButton toggleButtonAutoScroll;

    @FXML
    private ChoiceBox<Level> choiceBoxLogLevel;

    @FXML
    void handleRemoveSelected() {
        listViewLog.getItems().removeAll(listViewLog.getSelectionModel().getSelectedItems());
    }

    @FXML
    void handleClearLog() {
        listViewLog.getItems().clear();
    }

    @FXML
    void initialize() {
        listViewLog.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
        LoggerContext loggerContext = (LoggerContext) LogManager.getContext(false);
        Configuration loggerConfiguration = loggerContext.getConfiguration();
        LoggerConfig loggerConfig = loggerConfiguration.getLoggerConfig(LogManager.ROOT_LOGGER_NAME);
        /* ChoiceBox füllen */
        for (Level level : Level.values()) {
            choiceBoxLogLevel.getItems().add(level);
        }
        /* Aktuellen LogLevel in der ChoiceBox als Auswahl setzen */
        choiceBoxLogLevel.getSelectionModel().select(loggerConfig.getLevel());
        choiceBoxLogLevel.getSelectionModel().selectedItemProperty().addListener(new ChangeListener<Level>() {
            @Override
            public void changed(ObservableValue<? extends Level> arg0, Level oldLevel, Level newLevel) {
                loggerConfig.setLevel(newLevel);
                loggerContext.updateLoggers(); // übernehme aktuellen LogLevel
            }
        });

        listViewLog.setCellFactory(new Callback<ListView<String>, ListCell<String>>() {
            @Override
            public ListCell<String> call(ListView<String> listView) {
                return new LogStringCell();
            }
        });

        /* den Origial System.out Stream in die ListView umleiten */
        PipedOutputStream pOut = new PipedOutputStream();
        System.setOut(new PrintStream(pOut));
        PipedInputStream pIn = null;
        try {
            pIn = new PipedInputStream(pOut);
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        BufferedReader reader = new BufferedReader(new InputStreamReader(pIn));

        Task<Void> task = new Task<Void>() {
            @Override
            protected Void call() throws Exception {
                while (!isCancelled()) {
                    try {
                        String line = reader.readLine();
                        if (line != null) {
                            Platform.runLater(new Runnable() {
                                @Override
                                public void run() {
                                    listViewLog.getItems().add(line);

                                    /* Auto-Scroll + Select */
                                    if (toggleButtonAutoScroll.selectedProperty().get()) {
                                        listViewLog.scrollTo(listViewLog.getItems().size() - 1);
                                        listViewLog.getSelectionModel().select(listViewLog.getItems().size() - 1);
                                    }
                                }
                            });
                        }
                    }
                    catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                return null;
            }
        };
        Thread thread = new Thread(task);
        thread.setDaemon(true);
        thread.start();
    }
}

该LogStringCell.class

package tuc.plentyfx.common;

import javafx.scene.control.ListCell;
import javafx.scene.layout.FlowPane;
import javafx.scene.text.Text;

public class LogStringCell extends ListCell<String> {

    @Override
    protected void updateItem(String string, boolean empty) {
        super.updateItem(string, empty);
        if (string != null && !isEmpty()) {
            setGraphic(createAssembledFlowPane(string));
        }
        else {
            setGraphic(null);
            setText(null);
        }
    }

    /* Erzeuge ein FlowPane mit gefüllten Textbausteien */
    private FlowPane createAssembledFlowPane(String... messageTokens) {
        FlowPane flow = new FlowPane();
        for (String token : messageTokens) {
            Text text = new Text(token);

            if (text.toString().contains(" TRACE ")) {
                text.setStyle("-fx-fill: #0000FF");
            }
            if (text.toString().contains(" ALL ")) {
                text.setStyle("-fx-fill: #FF00FF");
            }
            if (text.toString().contains(" ERROR ")) {
                text.setStyle("-fx-fill: #FF8080");
            }
            if (text.toString().contains(" INFO ")) {
                text.setStyle("-fx-fill: #000000");
            }
            if (text.toString().contains(" FATAL ")) {
                text.setStyle("-fx-fill: #FF0000");
            }
            if (text.toString().contains(" DEBUG ")) {
                text.setStyle("-fx-fill: #808080");
            }
            if (text.toString().contains(" OFF ")) {
                text.setStyle("-fx-fill: #8040FF");
            }
            if (text.toString().contains(" WARN ")) {
                text.setStyle("-fx-fill: #FF8000");
            }

            flow.getChildren().add(text);
        }
        return flow;
    }
}

第3步:在您的应用程序中使用它.完成...!

问题/想法/限制: 当我的代码与线程一起使用时,我的代码目前存在一些问题:从另一个线程创建一个日志语句会破坏管道流并抛出错误.也许需要一个同步管道.我发现谷歌的代码,但没有尝试它(也看这里:http://www.certpal.com/blogs/2010/11/using-a-pipedinputstream-and-pipedoutputstream/ ):

package application.common;

import java.io.InputStream;
import java.io.OutputStream;

public class SyncPipe implements Runnable {

    private final OutputStream outputStream;
    private final InputStream inputStream;

    public SyncPipe(InputStream inputStream, OutputStream outputStream) {
        this.inputStream = inputStream;
        this.outputStream = outputStream;
    }

    @Override
    public void run() {
        try {
            final byte[] buffer = new byte[1024];
            for (int length = 0; (length = inputStream.read(buffer)) != -1;) {
                outputStream.write(buffer, 0, length);
            }
        }
        catch (Exception e) {
            e.printStackTrace();
        }
    }

}

另一个问题:应该使用更好的检测日志消息类型(信息,调试,跟踪等)来重新编码彩色字符串格式.使用诸如"text.toString().contains("TRACE"))"之类的内容进行过滤非常难看.

如果您对此有任何疑问,请与我们联系.这个帖子真的很旧但如果你在这里写,我会收到一封电子邮件.然后我可以直接回答你