以编程方式设置 Logback Appender 路径

我正在尝试以编程方式设置 Logback 附加程序路径。 （滚动文件附加器 http://logback.qos.ch/apidocs/ch/qos/logback/core/rolling/RollingFileAppender.html准确地说是固定窗口滚动策略）

我这样做是因为我想让我的用户能够在首选项对话框中设置日志路径（Eclipse RCP）

我已经尝试过类似的方法，但我没有更改配置文件中定义的日志路径：

Logger logback_logger = (ch.qos.logback.classic.Logger)LoggerFactory
   .getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
RollingFileAppender<ILoggingEvent> rfappender = 
   (RollingFileAppender<ILoggingEvent>)logback_logger.getAppender("FILE");
rfappender.setFile(newFile);
FixedWindowRollingPolicy rollingPolicy = 
   (FixedWindowRollingPolicy)rfappender.getRollingPolicy();
rollingPolicy.setFileNamePattern(newPattern);

一旦你以编程方式配置你的appender，你需要调用它的start()方法。如果appender有子组件，则调用start()首先是子组件。然后，您将附加程序添加到您选择的记录器中。

这是一个例子：

import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.encoder.PatternLayoutEncoder;
import ch.qos.logback.core.rolling.FixedWindowRollingPolicy;
import ch.qos.logback.core.rolling.RollingFileAppender;
import ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy;
import ch.qos.logback.core.util.StatusPrinter;
import org.slf4j.LoggerFactory;
import ch.qos.logback.classic.LoggerContext;

public class Main {
  public static void main(String[] args) {
    LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();

    RollingFileAppender rfAppender = new RollingFileAppender();
    rfAppender.setContext(loggerContext);
    rfAppender.setFile("testFile.log");
    FixedWindowRollingPolicy rollingPolicy = new FixedWindowRollingPolicy();
    rollingPolicy.setContext(loggerContext);
    // rolling policies need to know their parent
    // it's one of the rare cases, where a sub-component knows about its parent
    rollingPolicy.setParent(rfAppender);
    rollingPolicy.setFileNamePattern("testFile.%i.log.zip");
    rollingPolicy.start();

    SizeBasedTriggeringPolicy triggeringPolicy = new ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy();
    triggeringPolicy.setMaxFileSize("5MB");
    triggeringPolicy.start();

    PatternLayoutEncoder encoder = new PatternLayoutEncoder();
    encoder.setContext(loggerContext);
    encoder.setPattern("%-4relative [%thread] %-5level %logger{35} - %msg%n");
    encoder.start();

    rfAppender.setEncoder(encoder);
    rfAppender.setRollingPolicy(rollingPolicy);
    rfAppender.setTriggeringPolicy(triggeringPolicy);

    rfAppender.start();

    // attach the rolling file appender to the logger of your choice
    Logger logbackLogger = loggerContext.getLogger("Main");
    logbackLogger.addAppender(rfAppender);

    // OPTIONAL: print logback internal status messages
    StatusPrinter.print(loggerContext);

    // log something
    logbackLogger.debug("hello");
  }
}

上面的代码是 logback 的 XML 配置器（即 Joran）在解析滚动固定窗口.xml https://github.com/qos-ch/logback/blob/master/logback-examples/src/main/resources/chapters/appenders/conf/logback-RollingFixedWindow.xml file.