Processing schedule timed tasks in the Spring boot project

After initialization, we allow support for schedule in the Spring Boot entry class Application.java

@SpringBootApplication@EnableSchedulingpublic class Application {    public static void main(String[] args) {        SpringApplication.run(Application.class, args);    }}

Then, create a new execution class Jobs.java

@Componentpublic class Jobs {    public final static long ONE_Minute =  60 * 1000;        @Scheduled(fixedDelay=ONE_Minute)    public void fixedDelayJob(){        System.out.println(Dates.format_yyyyMMddHHmmss(new Date())+" >>fixedDelay执行");    }        @Scheduled(fixedRate=ONE_Minute)    public void fixedRateJob(){        System.out.println(Dates.format_yyyyMMddHHmmss(new Date())+" >>fixedRate执行");    }    @Scheduled(cron="0 15 3 * * ?")    public void cronJob(){        System.out.println(Dates.format_yyyyMMddHHmmss(new Date())+" >>cron执行");    }}

This is the simplest of 2 ways, how many minutes to execute once, Fixeddelay and fixedrate, the unit is milliseconds, so 1 minutes is 60 seconds x1000
The difference is that fixedrate is once every few minutes, no matter how much time you spend doing business. I was executed 1 times in 1 minutes, and Fixeddelay was executed 1 minutes after the task was executed. So depending on the actual business, we will choose different ways.

And there is a class of timed tasks, such as 3:15 per day, so we need another way: cron expressions

Cron expressions, have a special syntax, and feel a bit around people, but in simple terms, we remember some common usage, special grammar can be checked separately.
Cron has a total of 7, but the last one is years and can be left blank, so we can write 6 bits:

• First digit, indicating seconds, value 0-59
• Second position, the value of 0-59
• The third digit, which represents the hour, is valued at 0-23
• Fourth digit, date day/day, value 1-31
• Fifth digit, date month, value 1-12
• Sixth place, week, value 1-7, Monday, Tuesday ..., note: Not 1th week, second week meaning
  In addition: 1 represents Sunday, 2 represents Monday.
• 7th, year, can be left blank, value 1970-2099
  Cron, there are some special symbols, meaning the following:

() Asterisk: can be understood as each meaning, per second, per minute, daily, monthly, every year ...
(?) Question mark: The question mark can only appear in the date and week two positions, indicating that the value of this position is indeterminate, 3 points per day, so the sixth position of the week, we do not need to pay attention to, that is, indeterminate value. At the same time: the date and week are two mutually exclusive elements, with a question mark indicating that no value is specified. For example, January 10, such as the Week 1, if the location of the week is another designated Tuesday, the conflict conflicts.
(-) minus sign: Expresses a range, such as using "10-12" in the hour field, which means from 10 to 12 points, i.e. 10,11,12
(,) Comma: Expresses a list value, such as "1,2,4" in the week field, which means Monday, Tuesday, Thursday
(/) Slash: such as: X/y,x is the start value, Y is the step, such as in the first bit (seconds) 0/15 is, starting from 0 seconds, every 15 seconds, the last is 0,15,30,45,60 another:/y, equivalent to 0/y
Here are a few examples for you to verify:

0 0 3 * *? 3-point execution per day
0 5 3 * *? Performed 3:5 daily
0 5 3? * * Daily 3:5, same as above
0 5/10 3 * *? 3 points per day, 5 points, 15 points, 25 points, 35 points, 45 points, 55 points these hours are executed.
0 10 3? * 1 per week Sunday, 3:10 execution, note: 1 = Sunday
0 10 3? * 1#3 The third week of each month, executed in Sunday, #号只能出现在星期的位置

Processing schedule timed tasks in the Spring boot project