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stay springboot Let the task be executed regularly
First add… To the entry class @EnableScheduling annotation
@EnableScheduling
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}Add… To the specified task method to be executed regularly @Scheduled annotation
@Service
public class ScheduledService {
/* second branch when Japan month Zhou
* corn An example of an expression in ：0 * * * * *
* It means that every day, every hour, every minute of every month 0 In seconds
* */
@Scheduled(cron = "0-50 * * * * *")
public void scheduledHello(){
System.out.println("hello...");
}
}Write… In the notes cron The expression can meet the corresponding time requirements , For example, the example code indicates that for the first time in any minute 0 Second to the first 50 Every second will output “hello…”
cron expression
Cron expression Is a string , character string With 5 or 6 Space between , It is divided into 6 or 7 Domains , Each domain represents a meaning ,Cron There are two grammatical formats as follows ：（1） second branch when date month The week of the week year
（2） second branch when date month The week of the week
| Field | permitted | Special characters allowed |
| second （Seconds） | 0~59 The integer of | , – * / |
| branch （Minutes） | 0~59 The integer of | , – * / |
| Hours （Hours） | 0~53 The integer of | , – * / |
| date （DayofMonth） | 1~31 The integer of （ Pay attention to the days of the month ） | , – * / ? L W C |
| month （Month） | 1~12 The integer of | , – * / |
| week （DayofWeek） | 0-7 or SUN-SAT,0 and 7 yes SUN | , – * / ? L C # |
| Special characters | meaning |
| ,（ English comma ） | enumeration |
| -（ minus sign ） | Section |
| * | arbitrarily |
| / | Interval step size |
| ？ | Japan / Week conflict match |
| L | Last |
| W | Working day |
| C | and calendar Calculated value after contact |
| # | week ,4#2 It means the next Thursday |