fix 避免空打印

monitors/monitorHelper.go

@@ -12,8 +12,10 @@ type MonitorHelper struct {
 
 func (the *MonitorHelper) initial() {
 	the.Cron = cron.New()
+	if the.CronStr != "" {
 		log.Printf("cronStr=%s", the.CronStr)
 	}
+}
 
 // RegisterTask 注册定时器方法
 func (the *MonitorHelper) registerTask(cron string, task func()) {