@Schedule annotation is used to specify the execution time and frequency of scheduled tasks

Below is a detailed explanation of all parameters:

second: seconds, value range: 0~59;

minute: Minutes, value range: 0~59;

hour: hour, value range: 0~23;

dayOfMonth: A certain day in the month, value range: 1~31;

month: Month, value range: 1~12;

dayOfWeek: Day of the week, value range: 1~7, where 1 means Sunday, 2 means Monday, and so on;

year: year, value range: 1970~2099;

persistent: Whether to persist, the default is true. If true, it means that these scheduled tasks should continue to run even after the application is restarted; if false, it means that these scheduled tasks will no longer run after the application is restarted;

info: Task description information;

timezone: Time zone, the default value is "GMT".

Use expressions to control task execution time:

In addition to the above parameters, the @Schedule annotation also supports the use of expressions to control the execution time of tasks. The expression is in the form of a cron expression. This expression defines the time interval and rules for scheduling the execution of the program. The cron expression consists of 6 space-separated time fields. These fields represent, in order, seconds, minutes, hours, date, month, and day of the week. Each field has a set of allowed values, as well as some special characters that can be used to specify different options for execution time. Below is a detailed description of each field:

1. Second (0-59): Indicates which second in one minute the task is executed. For example, cron = "0/5 * * * * *" means starting from 0 seconds and executing the task every 5 seconds.

2. Minute (0-59): Indicates which minute of the hour the task is performed. For example, cron = "0 0/10 * * * *" means that the task will be executed every 10 minutes, starting from 0 minutes.

3. Hour (0-23): Indicates the hour of the day to perform the task. For example, cron = "0 0 12 * * *" means that the task will be executed at 12 noon every day.

4. Date (1-31): Indicates the day of the month to perform the task. For example, cron = "0 0 0 25 12 ?" means that the task is executed at zero o'clock on December 25th every year.

5. Month (1-12): Indicates which month of the year the task is performed. For example, cron = "0 0 0 1 * *" means executing the task on the first day of every month.

6. Day of the week (0-7, Sunday = 0 or 7): Indicates which day of the week the task is performed. For example, cron = "0 0 0 ? * SUN" means executing the task every Sunday.

Note: "*" in a cron expression means all possible values, while "?" means no value is specified (usually used for date and week fields).

Here are some other examples:

• 0 0 0 * * *Indicates that the task will be executed at midnight every day
• 0 0 12 * * ?Indicates that the task will be executed at 12 noon every day
• 0 15 10 ? * *Indicates that the task will be executed at 10:15 am every day
• 0 0/5 * * * ?Indicates that starting from 0 seconds, the task will be executed every 5 minutes

Here is an example using the @Schedule annotation:

@Service
public class MyTimer {

    @Schedule(second="*/10", minute="*", hour="*")
    public void execute() {
        System.out.println("定时任务执行了！");
    }
}

The above code indicates that a scheduled task will be executed every 10 seconds.