如何配置 slf4j 和 logback 以允许一个类记录到单独的文件？

Question

我有一个多线程的 Java 类，我希望它记录到一个单独的文件中。我正在使用 Dropwizard，它使用 logback 并在我的 YAML 文件中进行配置，如下所示：

    logging:
  # The default level of all loggers. Can be OFF, ERROR, WARN, INFO, DEBUG, TRACE, or ALL.
  level: INFO
  # Logger-specific levels.
  loggers:
    # Sets the level for 'com.example.app' to DEBUG.
    com.mycode: DEBUG

  appenders:
    - type: console
      threshold: DEBUG
    - type: file
      threshold: INFO
      logFormat: "%-6level [%d{HH:mm:ss.SSS}] [%t] %logger{5} - %X{code} %msg %n"
      currentLogFilename: /tmp/fingage.log
      archivedLogFilenamePattern: /tmp/project-%d{yyyy-MM-dd}-%i.log.gz
      archivedFileCount: 7
      timeZone: UTC
      maxFileSize: 10MB

在我的特殊班级中，我正在尝试类似的事情：

//Obtain an instance of LoggerContext
    LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();

    //Create a new FileAppender
    FileAppender<ILoggingEvent> file = new FileAppender<ILoggingEvent>();
    file.setName("FileLogger");
    file.setFile("specialclass.log");
    file.setContext(context);
    file.setAppend(true);

    //Filter out anything < WARN
    ThresholdFilter warningFilter = new ThresholdFilter();
    warningFilter.setLevel("WARN");
    warningFilter.setContext(context);
    warningFilter.start();
    file.addFilter(warningFilter);

    //Message Encoder
    PatternLayoutEncoder ple = new PatternLayoutEncoder();
    ple.setContext(context);
    ple.setPattern("%date %level [%thread] %logger{10} %msg%n");
    ple.start();
    file.setEncoder(ple);

    file.start();

    //Get ROOT logger, and add appender to it
    log = context.getLogger(MySpecialClass.class);
    log.setLevel(Level.DEBUG);
    log.addAppender(file);

    log.info("Hello Special Class");

不幸的是，它似乎没有改变任何东西，尽管我确实看到了一个空白文件specialclass.log，并且我的日志消息仅出现在控制台中。

Answer 1

答案是在 dropwizard YAML 文件中添加以下内容：

    logging:
  # The default level of all loggers. Can be OFF, ERROR, WARN, INFO, DEBUG, TRACE, or ALL.
  level: INFO
  # Logger-specific levels.
  loggers:
    
    com.mycode:
        level: DEBUG
        additive: false 
        appenders:
          - type: file
            currentLogFilename: /tmp/myclass.log
            

  appenders:
    - type: console
      threshold: DEBUG
    - type: file
      threshold: INFO
      logFormat: "%-6level [%d{HH:mm:ss.SSS}] [%t] %logger{5} - %X{code} %msg %n"
      currentLogFilename: /tmp/project.log
      archivedLogFilenamePattern: /tmp/project-%d{yyyy-MM-dd}-%i.log.gz
      archivedFileCount: 7
      timeZone: UTC
      maxFileSize: 10MB