text: // load log4js package
  var log4js = require('log4js');
  
  // config log4js
  log4js.configure({
      appenders: [
          {
              type: 'console', // out console platform
              category: 'console'
          },
          {
              type: 'dateFile',
              filename: 'logs/application.log',
              pattern: '-yyyy-MM-dd',
              alwaysIncludePattern: false,
              category: 'dateFilelog',
          }
      ],
  
      replaceConsole: true, // allow replace console
      levels: {
          console: 'DEBUG',
          dateFilelog: 'DEBUG'
      }
  })
  
  // output logger
  var logger = log4js.getLogger('console');
  var dateFileLogger = log4js.getLogger('dateFilelog');
  
  exports.logger = logger
  
  exports.use = function(app) {
      // 打印debug级别以上的日志级别
      log4js.connectLogger(dateFileLogger, { level: 'DEBUG', format: ':method :url'});
  }