How to solve the truncation of Java string attribute value that begins with a single number

Today, the editor will share with you how to solve the truncation of Java string attribute values starting with a single number. The content is detailed and the logic is clear. I believe most people still know too much about this knowledge, so share this article for your reference. I hope you can get something after reading this article. Let's take a look at it.

Brief introduction

When I tried to parameterize the CRON plan of the Spring task with environment variables, I encountered a problem that I did not receive the full plan from the property, but only if the first value was a number. Google search gives me zero examples of my problem type, so I'm on my own.

The solution I found involved using separate environment variables for each part of the plan.

Use the code

The attached Maven-based project is a simple project where the Spring task prints the current time to the console. I use Intellij's IDEA, but you should be able to adjust it to Eclipse or any other IDE you like.

The task classes are:

Public class ScheduledTasks {private static final Logger log = LoggerFactory.getLogger (ScheduledTasks.class); private static final SimpleDateFormat dateFormat = new SimpleDateFormat ("HH:mm:ss"); @ Scheduled (cron = "${cron.schedule}") public void reportCurrentTime () {log.info ("The time is now {}", dateFormat.format (new Date ();}}

In my application.properties, I initially set the timesheet from a single environment variable:

Cron.schedule = ${test_cron}

What if I use * / 5 *? The CRON of "" (every 5 seconds) set in the environment variable "test_cron" plans to run this program, and I will get the expected results:

2021-04-29 12 o.s.s.c.ThreadPoolTaskScheduler o.s.s.c.ThreadPoolTaskScheduler: Initializing ExecutorService 'taskScheduler'2021-04-29 12 INFO 22420-- [main] c.e.s.SchedulingTasksApplication: Started SchedulingTasksApplication in 2.441 seconds (JVM running for 3.931) 2021-04-29 12 INFO 55.008 INFO 22420-- [scheduling -1] c.e.schedulingtasks.ScheduledTasks: The time is now 12 c.e.schedulingtasks.ScheduledTasks 17 INFO 552021-04-29 12 INFO 1814 INFO 22420-[scheduling-1] c.e.schedulingtasks.ScheduledTasks: The time is now 12Vera 18Vera 002021-04-29 12Rd 18Vera 05.005 INFO 22420-- [scheduling-1] c.e.schedulingtasks.ScheduledTasks: The time is now 12:18:05

But if I run it with a schedule of "0 25 *?" (in the past 25 minutes), I get an error message indicating that my schedule is invalid and that there are only zeros in it:

Encountered invalid @ Scheduled method 'reportCurrentTime': For input string: "" 0 "

To solve this problem, I changed the application properties to use a variable in each plan section of the Environment, with a space in the middle:

Cron.schedule = ${cron_sec} ${cron_min} ${cron_hr} ${cron_day} ${cron_mth} ${cron_wk}

And run it with each environment variable set to the desired value. Similar to the above example of failure:

Cron_sec=0cron_min=30cron_hr=*cron_day=*cron_mth=*cron_wk=*

I got the expected output:

2021-04-29 12 c.e.s.SchedulingTasksApplication c.e.s.SchedulingTasksApplication: Started SchedulingTasksApplication in 3.677 seconds (JVM running for 5.441) 2021-04-29 12 c.e.s.SchedulingTasksApplication 30 Started SchedulingTasksApplication in 00.003 INFO 22896-[scheduling-1] c.e.schedulingtasks.ScheduledTasks above is "how to solve the truncation of Java string attribute values starting with a single number". Thank you for reading! I believe you will gain a lot after reading this article. The editor will update different knowledge for you every day. If you want to learn more knowledge, please pay attention to the industry information channel.