log4j日志应用 - pingdongyi/blog-2 GitHub Wiki

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private static final org.apache.log4j.Logger logger = LogManager.getLogger(UserController.class);
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logger.info("user_log_test_log4j");

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private final static org.slf4j.Logger LOGGER = org.slf4j.LoggerFactory.getLogger(UserController.class);
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LOGGER.debug("user_log_test_slf4j");

public class LogManager {

  /**
   * @deprecated This variable is for internal use only. It will
   * become package protected in future versions.
   * */
  static public final String DEFAULT_CONFIGURATION_FILE = "log4j.properties";
  
  static final String DEFAULT_XML_CONFIGURATION_FILE = "log4j.xml";  
   
  /**
   * @deprecated This variable is for internal use only. It will
   * become private in future versions.
   * */
  static final public String DEFAULT_CONFIGURATION_KEY="log4j.configuration";

  /**
   * @deprecated This variable is for internal use only. It will
   * become private in future versions.
   * */
  static final public String CONFIGURATOR_CLASS_KEY="log4j.configuratorClass";

  /**
  * @deprecated This variable is for internal use only. It will
  * become private in future versions.
  */
  public static final String DEFAULT_INIT_OVERRIDE_KEY = 
                                                 "log4j.defaultInitOverride";


  static private Object guard = null;
  static private RepositorySelector repositorySelector;

  static {
    // By default we use a DefaultRepositorySelector which always returns 'h'.
    Hierarchy h = new Hierarchy(new RootLogger((Level) Level.DEBUG));
    repositorySelector = new DefaultRepositorySelector(h);

    /** Search for the properties file log4j.properties in the CLASSPATH.  */
    String override =OptionConverter.getSystemProperty(DEFAULT_INIT_OVERRIDE_KEY,
						       null);

    // if there is no default init override, then get the resource
    // specified by the user or the default config file.
    if(override == null || "false".equalsIgnoreCase(override)) {

      String configurationOptionStr = OptionConverter.getSystemProperty(
							  DEFAULT_CONFIGURATION_KEY, 
							  null);

      String configuratorClassName = OptionConverter.getSystemProperty(
                                                   CONFIGURATOR_CLASS_KEY, 
						   null);

      URL url = null;

      // if the user has not specified the log4j.configuration
      // property, we search first for the file "log4j.xml" and then
      // "log4j.properties"
      if(configurationOptionStr == null) {	
	url = Loader.getResource(DEFAULT_XML_CONFIGURATION_FILE);
	if(url == null) {
	  url = Loader.getResource(DEFAULT_CONFIGURATION_FILE);
	}
      } else {
	try {
	  url = new URL(configurationOptionStr);
	} catch (MalformedURLException ex) {
	  // so, resource is not a URL:
	  // attempt to get the resource from the class path
	  url = Loader.getResource(configurationOptionStr); 
	}	
      }
      
      // If we have a non-null url, then delegate the rest of the
      // configuration to the OptionConverter.selectAndConfigure
      // method.
      if(url != null) {
	    LogLog.debug("Using URL ["+url+"] for automatic log4j configuration.");
        try {
            OptionConverter.selectAndConfigure(url, configuratorClassName,
					   LogManager.getLoggerRepository());
        } catch (NoClassDefFoundError e) {
            LogLog.warn("Error during default initialization", e);
        }
      } else {
	    LogLog.debug("Could not find resource: ["+configurationOptionStr+"].");
      }
    } else {
        LogLog.debug("Default initialization of overridden by " + 
            DEFAULT_INIT_OVERRIDE_KEY + "property."); 
    }  
  }
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}