code: function(key) {
          var num = parseInt(this.loadVar(key));
          if (isNaN(num)) {
              exitProcess('the value of ' +key+' is a necessary int ,but get ' + num, this.alarm);
              return false;
          }
          return num;
      }
docs: Get integer value by key, the value must be exist, otherwise the process will exit.
  
  @param {KeyItem} key
  @returns {Integer}