无法在@Scheduled注释中使用@ConfigurationProperties

我正在使用 @ConfigurationProperties 来定义属性my.delay.

@ConfigurationProperties( "my" )
public class MyProperties {

    private long delay = 1000L;

    public long getDelay() {
        return delay;
    }
    public void setDelay(long delay) {
        this.delay = delay;
    }
}

在调度程序方法中我尝试使用my.delay:

@SpringBootApplication
@EnableScheduling
@EnableConfigurationProperties( { MyProperties.class } )
public class TestSprPropApplication {

    public static void main(String[] args) {
        SpringApplication.run(TestSprPropApplication.class, args);
    }

    @Scheduled( fixedDelayString = "${my.delay}" )
    public void schedule() {
        System.out.println( "scheduled" );
    }
}

然后就会出现下面的错误：

Caused by: java.lang.IllegalStateException: Encountered invalid @Scheduled method 'schedule': Could not resolve placeholder 'my.delay' in string value "${my.delay}"
    at org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor.processScheduled(ScheduledAnnotationBeanPostProcessor.java:454) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor.postProcessAfterInitialization(ScheduledAnnotationBeanPostProcessor.java:324) ~[spring-context-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:423) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1633) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.6.RELEASE.jar:4.3.6.RELEASE]

您可以使用 SpEL 表达式来解决它引用一个bean https://docs.spring.io/spring/docs/current/spring-framework-reference/html/expressions.html#expressions-bean-references using @beanName.

你会这样使用它：

@Scheduled(fixedDelayString = "#{@myProperties.delay}")

请注意#{}使用（SpEL 表达式）代替${}（属性占位符）。