标签：tasks String 55 spring 09 link time Scheduling org

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

标签：tasks,String,55,spring,09,link,time,Scheduling,org
来源： https://blog.csdn.net/yuyanchuan/article/details/114010660

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