log4j配置文件详解---转

使用步骤注意：

1. 从http://logging.apache.org/log4j/1.2/ 下载文件

2. 在src目录下加入log4j.properties，将jar包放入build -path，log4j.properties 编译后位于/classes目录下。

3.  配置文件读取解析：

     PropertyConfigurator.configure(String configFilename)---->

PropertyConfigurator.java

  staticpublic void configure(String configFilename) {
    new PropertyConfigurator().doConfigure(configFilename,
                       LogManager.getLoggerRepository());
  }

--->读取配置文件

 public
  void doConfigure(String configFileName, LoggerRepository hierarchy) {
    Properties props = new Properties();
    FileInputStream istream = null;
    try {
      istream = new FileInputStream(configFileName);
      props.load(istream);
      istream.close();
    }
    catch (Exception e) {
      if (e instanceof InterruptedIOException || e instanceof InterruptedException) {
          Thread.currentThread().interrupt();
      }
      LogLog.error("Could not read configuration file ["+configFileName+"].", e);
      LogLog.error("Ignoring configuration file [" + configFileName+"].");
      return;
    } finally {
        if(istream != null) {
            try {
                istream.close();
            } catch(InterruptedIOException ignore) {
                Thread.currentThread().interrupt();
            } catch(Throwable ignore) {
            }

        }
    }
    // If we reach here, then the config file is alright.
    doConfigure(props, hierarchy);
  }

-->读取配置

  /**
     Read configuration options from <code>properties</code>.

     See {@link #doConfigure(String, LoggerRepository)} for the expected format.
  */
  public
  void doConfigure(Properties properties, LoggerRepository hierarchy) {
    repository = hierarchy;
    String value = properties.getProperty(LogLog.DEBUG_KEY);
    if(value == null) {
      value = properties.getProperty("log4j.configDebug");
      if(value != null) {
        LogLog.warn("[log4j.configDebug] is deprecated. Use [log4j.debug] instead.");
    }
    }

    if(value != null) {
      LogLog.setInternalDebugging(OptionConverter.toBoolean(value, true));
    }

      //
      //   if log4j.reset=true then
      //        reset hierarchy
    String reset = properties.getProperty(RESET_KEY);
    if (reset != null && OptionConverter.toBoolean(reset, false)) {
          hierarchy.resetConfiguration();
    }

    String thresholdStr = OptionConverter.findAndSubst(THRESHOLD_PREFIX,
                               properties);
    if(thresholdStr != null) {
      hierarchy.setThreshold(OptionConverter.toLevel(thresholdStr,
                             Level.ALL));
      LogLog.debug("Hierarchy threshold set to ["+hierarchy.getThreshold()+"].");
    }
    
    configureRootCategory(properties, hierarchy);
    configureLoggerFactory(properties);
    parseCatsAndRenderers(properties, hierarchy);

    LogLog.debug("Finished configuring.");
    // We don't want to hold references to appenders preventing their
    // garbage collection.
    registry.clear();
  }

 

原文：http://zengjinliang.iteye.com/blog/171550

一：log4j配置文件基本含义说明 

    } 
} 
运行一下，看看异常信息是不是保存在了一个单独的文件error.log中。