code: function(key) {
          var value;
          if (key.indexOf('.') == -1) {
              value = this.configObj[key];
          } else {
              var keyArray = key.split('.');
              var keyStr = keyArray[0];
              value = this.configObj[keyStr];
              for(var i= 1,len=keyArray.length;i<len;i++) {
                  if (!value && i < len-1) {
                      exitProcess('the var ['+keyStr + '] is empty.', this.alarm);
                      return undefined;
                  }
                  var keyNow = keyArray[i];
                  keyStr += '.'+keyNow;
                  value = value[keyNow];
              }
          }
          slogger.debug('load var ['+key+'],value:',value);
          return value;
      }
docs: Get value by key
  
  @param {KeyItem} key
  @returns {String|Object}