spring
创建一个spring程序，用于定时任务的调度
pom
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<parent>
<artifactId>springdemo</artifactId>
<groupId>org.example</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>Scheduling-tasks</artifactId>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>2.4.2</version>
</dependency>
<dependency>
<groupId>org.awaitility</groupId>
<artifactId>awaitility</artifactId>
<version>4.0.3</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<version>2.4.2</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
定时任务
@Component
public class ScheduledTasks {
private static final Logger log = LoggerFactory.getLogger(ScheduledTasks.class);
private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
@Scheduled(fixedRate = 5000)
public void reportCurrentTime() {
log.info("The time is now {}", dateFormat.format(new Date()));
}
}
Scheduled注解
/**
* Annotation that marks a method to be scheduled.用于标识一个方法用于调度用的
* Exactly one of the
* {@link #cron}, {@link #fixedDelay}, or {@link #fixedRate} attributes must be
* specified.
* 注解中必须要有以上一个的参数
*
* <p>The annotated method must expect no arguments. It will typically have
* a {@code void} return type; if not, the returned value will be ignored
* when called through the scheduler.
* 调度任务不能有参数
*
* <p>Processing of {@code @Scheduled} annotations is performed by
* registering a {@link ScheduledAnnotationBeanPostProcessor}. This can be
* done manually or, more conveniently, through the {@code <task:annotation-driven/>}
* element or @{@link EnableScheduling} annotation.
*
* <p>This annotation may be used as a <em>meta-annotation</em> to create custom
* <em>composed annotations</em> with attribute overrides.
*
* @author Mark Fisher
* @author Juergen Hoeller
* @author Dave Syer
* @author Chris Beams
* @since 3.0
* @see EnableScheduling
* @see ScheduledAnnotationBeanPostProcessor
* @see Schedules
*/
@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Repeatable(Schedules.class)
public @interface Scheduled {
/**
* A special cron expression value that indicates a disabled trigger: {@value}.
* <p>This is primarily meant for use with <code>${...}</code> placeholders,
* allowing for external disabling of corresponding scheduled methods.
* @since 5.1
* @see ScheduledTaskRegistrar#CRON_DISABLED
*/
String CRON_DISABLED = ScheduledTaskRegistrar.CRON_DISABLED;
/**
* A cron-like expression, extending the usual UN*X definition to include triggers
* on the second, minute, hour, day of month, month, and day of week.
* <p>For example, {@code "0 * * * * MON-FRI"} means once per minute on weekdays
* (at the top of the minute - the 0th second).
* <p>The fields read from left to right are interpreted as follows.
* <ul>
* <li>second</li>
* <li>minute</li>
* <li>hour</li>
* <li>day of month</li>
* <li>month</li>
* <li>day of week</li>
* </ul>
* <p>The special value {@link #CRON_DISABLED "-"} indicates a disabled cron
* trigger, primarily meant for externally specified values resolved by a
* <code>${...}</code> placeholder.
* @return an expression that can be parsed to a cron schedule
* @see org.springframework.scheduling.support.CronSequenceGenerator
*/
String cron() default "";
/**
* A time zone for which the cron expression will be resolved. By default, this
* attribute is the empty String (i.e. the server's local time zone will be used).
* @return a zone id accepted by {@link java.util.TimeZone#getTimeZone(String)},
* or an empty String to indicate the server's default time zone
* @since 4.0
* @see org.springframework.scheduling.support.CronTrigger#CronTrigger(String, java.util.TimeZone)
* @see java.util.TimeZone
*/
String zone() default "";
/**
* Execute the annotated method with a fixed period in milliseconds between the
* end of the last invocation and the start of the next.
* @return the delay in milliseconds
*/
long fixedDelay() default -1;
/**
* Execute the annotated method with a fixed period in milliseconds between the
* end of the last invocation and the start of the next.
* @return the delay in milliseconds as a String value, e.g. a placeholder
* or a {@link java.time.Duration#parse java.time.Duration} compliant value
* @since 3.2.2
*/
String fixedDelayString() default "";
/**
* Execute the annotated method with a fixed period in milliseconds between
* invocations.
* @return the period in milliseconds
*/
long fixedRate() default -1;
/**
* Execute the annotated method with a fixed period in milliseconds between
* invocations.
* @return the period in milliseconds as a String value, e.g. a placeholder
* or a {@link java.time.Duration#parse java.time.Duration} compliant value
* @since 3.2.2
*/
String fixedRateString() default "";
/**
* Number of milliseconds to delay before the first execution of a
* {@link #fixedRate} or {@link #fixedDelay} task.
* @return the initial delay in milliseconds
* @since 3.2
*/
long initialDelay() default -1;
/**
* Number of milliseconds to delay before the first execution of a
* {@link #fixedRate} or {@link #fixedDelay} task.
* @return the initial delay in milliseconds as a String value, e.g. a placeholder
* or a {@link java.time.Duration#parse java.time.Duration} compliant value
* @since 3.2.2
*/
String initialDelayString() default "";
}
使调度起作用
@SpringBootApplication
@EnableScheduling
public class Main {
public static void main(String[] args) {
SpringApplication.run(Main.class);
}
}
这样就能使任务定时执行了
2021-02-24 09:55:06.750 INFO 13612 --- [ scheduling-1] org.yyc.task.ScheduledTasks : The time is now 09:55:06
2021-02-24 09:55:11.748 INFO 13612 --- [ scheduling-1] org.yyc.task.ScheduledTasks : The time is now 09:55:11
2021-02-24 09:55:16.750 INFO 13612 --- [ scheduling-1] org.yyc.task.ScheduledTasks : The time is now 09:55:16
2021-02-24 09:55:21.749 INFO 13612 --- [ scheduling-1] org.yyc.task.ScheduledTasks : The time is now 09:55:21
2021-02-24 09:55:26.748 INFO 13612 --- [ scheduling-1] org.yyc.task.ScheduledTasks : The time is now 09:55:26
2021-02-24 09:55:31.749 INFO 13612 --- [ scheduling-1] org.yyc.task.ScheduledTasks : The time is now 09:55:31
2021-02-24 09:55:36.749 INFO 13612 --- [ scheduling-1] org.yyc.task.ScheduledTasks : The time is now 09:55:36