使用log4j2v2收集日志。9

Question

我有一个关于2.9版本的log4j2的问题。基本上，我想做的与这里描述的相同（log4j），只有2.9：示例log4j v1. x

我需要一个可以在类中的任何方法中调用的记录器。这是从某个起点递归地收集所有后续日志。该集合应该能够在以后以任何形式读出。

Logger logger = LogManager.getLogger();
public void meth1(){
  StringWriter/ List/ String or whatever
  logger.add(Collector);
  logger.info("Start");
  this.meth2();
  this.meht3();
  logger.info("Stop");
  => do something with the collected logs
}
public void meht2(){
  logger.info("meth2: add Collection");
}
public void meth3(){
  logger.info("meth3: add Collection");
}
public void meht4(){
  logger.info("foo");
}

在表单中设置结束后，集合中应包括以下日志：

• 开始

谢谢你的帮助

Answer 1

谢谢，我已经根据自己的需要进行了调整：

public static StringWriter createStringWriter(String classname){
    StringWriter stringWriter = new StringWriter();
    final LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
    final Configuration config = ctx.getConfiguration();
    PatternLayout layout = PatternLayout.newBuilder()
            .withPattern("%d{yyyy-MM-dd HH:mm:ss.SSS} %level [%t] [%c] [%M] [%l] - %msg%n").build();
    WriterAppender writerAppender = WriterAppender.newBuilder()
                                        .setName(classname + "writeLogger")
                                        .setTarget(stringWriter)
                                        .setLayout(layout)
                                        .build();
    writerAppender.start();
    config.addAppender(writerAppender);
    LoggerConfig loggerConfig = config.getLoggerConfig(classname);
    loggerConfig.addAppender(writerAppender, null, null);
    ctx.updateLoggers();
    return stringWriter;
}

public static void removeStringWriter(String classname){
    final LoggerContext ctx = (LoggerContext) LogManager.getContext(false);
    final Configuration config = ctx.getConfiguration();
    LoggerConfig loggerConfig = config.getLoggerConfig(classname);
    loggerConfig.removeAppender(classname + "writeLogger");
    ctx.updateLoggers();
}

Answer 2

过了一会儿，我想出了下面的解决方案，它适用于我使用log4j2.8。我在代码中添加了一些注释来解释不同的必要步骤。

请求记录器时必须使用与存储配置时相同的名称（标有/*1*/的行）（标有/*2*/的行）。这意味着不能使用类名获取记录器，或者MyClass.class.getName（）应在/*2*/处使用。

public class LoggingTest {

    public static void main(String[] args) {

        // define the logger, could also be static in class
        final String loggerName = "myCollectingLogger";
        Logger logger = LogManager.getLogger(loggerName); /* 1 */

        // the log message collector
        StringWriter writer = new StringWriter();

        // start adapting the logger configuration
        LoggerContext ctx = LoggerContext.getContext(false);
        Configuration config = ctx.getConfiguration();

        // create our appender
        PatternLayout layout = PatternLayout.newBuilder().withPattern("%d{yyyy-MM-dd HH:mm:ss.SSS} %level [%t] [%c] [%M] [%l] - %msg%n").build();
        WriterAppender writerAppender = WriterAppender.newBuilder().setName("writerAppender").setTarget(writer).setLayout(layout).build();

        // add the appender to a LoggerConfig
        AppenderRef ref = AppenderRef.createAppenderRef("writerAppender", null, null);
        AppenderRef[] refs = new AppenderRef[] { ref };
        LoggerConfig loggerConfig = LoggerConfig.createLogger(false, Level.INFO, "example", null, refs, null, config, null);
        loggerConfig.addAppender(writerAppender, null, null);

        // enable the LoggerConfig in the LoggerContext
        config.addLogger(loggerName, loggerConfig); /* 2 */
        ctx.updateLoggers();

        // use the logger:
        logger.info("Start");
        logger.warn("foo bar");
        logger.error("relax, it's just a test");
        logger.info("Stop");

        System.out.println("--- the collected log messages: ---");
        System.out.println(writer.toString());
    }
}