通过引用 bean 名称在@Scheduled注释中使用@ConfigurationProperties

java spring spring-boot

2022-09-04 08:44:19

我正在使用Spring boot配置后台任务的延迟，并且我正在尝试从另一个组件上的注释中使用此值。但是，为了使它起作用，我必须使用Spring给豆子的全名。@ConfigurationProperties@Scheduled

配置属性类如下所示：

@ConfigurationProperties("some")
class SomeProperties {
    private int millis; //the property is some.millis

    public int getMillis() {
        return millis;
    }

    public void setMillis(int millis) {
         this.millis = millis;
    }
}

我在计划方法中按如下方式使用该值：

@Component
class BackgroundTasks {

    @Scheduled(fixedDelayString = "#{@'some-com.example.demo.SomeProperties'.millis}") //this works.
    public void sayHello(){
        System.out.println("hello");
    }
}

是否可以在不使用 Bean 的全名的情况下引用该值？这个答案表明这是可能的，但我无法使它工作。

答案 1

在属性类上使用允许以的形式访问属性。@Component"#{@someProperties.persistence.delay}

更多信息请参阅弹簧启动文档。

答案 2

一些优点.java

package com.example.demo;

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.stereotype.Component;

@ConfigurationProperties("some")
@Component("someProperties")
public class SomeProperties {

    private int millis; // the property is some.millis

    public int getMillis() {
        return millis;
    }

    public void setMillis(int millis) {
        this.millis = millis;
    }

}

背景任务.java

package com.example.demo;

import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

@Component
public class BackgroundTasks {

    /**
     * 
     * Approach1: We can inject/access the property some.millis directly in @Value
     * fashion even though we have configured it to bind with SomeProperties class
     * using @ConfigurationProperties.
     * 
     * 
     */
    @Scheduled(fixedRateString = "${some.millis}")
    public void fromDirectInjection() {

        System.out.println("Hi, I'm  from DirectInjection method");

    }

    /**
     * 
     * Approach2: Add @Component on SomeProperties and access the bean bean's
     * property millis like below using Spring Expression language
     * 
     * 
     */
    @Scheduled(fixedRateString = "#{@someProperties.millis}")
    public void fromConfigurationProperty() {
        System.out.println("Hi, I'm from ConfigurationProperty method");

    }

}

演示应用程序.java

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;

@SpringBootApplication
@EnableScheduling
public class DemoApplication {

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

}

应用程序.属性

some.millis=2000

使用的版本

 SpringBoot 2.6.0

啪.xml

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.0-SNAPSHOT</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>11</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <releases>
                <enabled>false</enabled>
            </releases>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
        <pluginRepository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <releases>
                <enabled>false</enabled>
            </releases>
        </pluginRepository>
    </pluginRepositories>

</project>

输出：

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::       (v2.6.0-SNAPSHOT)

2021-10-08 08:38:03.342  INFO 8092 --- [           main] com.example.demo.DemoApplication         : Starting DemoApplication using Java 14.0.2 on TO-GZ9M403-L with PID 8092 (D:\workspaces\configprop\demo (1)\demo\target\classes started by D1 in D:\workspaces\configprop\demo (1)\demo)
2021-10-08 08:38:03.345  INFO 8092 --- [           main] com.example.demo.DemoApplication         : No active profile set, falling back to default profiles: default
2021-10-08 08:38:04.884  INFO 8092 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2021-10-08 08:38:04.902  INFO 8092 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-10-08 08:38:04.902  INFO 8092 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.53]
2021-10-08 08:38:05.050  INFO 8092 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-10-08 08:38:05.050  INFO 8092 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 1631 ms
2021-10-08 08:38:05.644  INFO 8092 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
Hi, I'm  from DirectInjection method
Hi, I'm from ConfigurationProperty method
2021-10-08 08:38:05.662  INFO 8092 --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 2.995 seconds (JVM running for 3.712)
Hi, I'm  from DirectInjection method
Hi, I'm from ConfigurationProperty method
Hi, I'm  from DirectInjection method
Hi, I'm from ConfigurationProperty method
Hi, I'm  from DirectInjection method
Hi, I'm from ConfigurationProperty method