springboot - 应用实践（N）使用springboot内置的@Scheduled

1、springboot开箱即用，内置调度任务的使用。

建一个简单的springboot工程，pom.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>2.1.8.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.lfy</groupId>
    <artifactId>javatestproject</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>javatestproject</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</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>

</project>

2、使用@Scheduled

package com.lfy.javatestproject.start;

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

@Component
public class TaskDemo {

    /**
     * 每5秒执行一次
     */
    @Scheduled(cron = "0/5 * * * * ? ")
    public void sayHello(){
        System.out.println("Hello.");
    }

    /**
     * 每2秒执行一次
     */
    @Scheduled(fixedRate = 2000)
    public void sayHappy(){
        System.out.println("I am Happy.");
    }
}

3、将启动项注解@EnableScheduling

package com.lfy.javatestproject;

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

@EnableScheduling
@SpringBootApplication
public class JavatestprojectApplication {

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

}

4、运行查看

"C:\Program Files\Java\jdk1.8.0_65\bin\java.exe" -XX:TieredStopAtLevel= -noverify -Dspring.output.ansi...

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.8.RELEASE)

-- ::31.403  INFO  --- [           main] c.l.j.JavatestprojectApplication         : Starting JavatestprojectApplication on DESKTOP-V80IF6T with PID ...
-- ::31.418  INFO  --- [           main] c.l.j.JavatestprojectApplication         : No active profile set, falling back to default profiles: default
-- ::31.935  INFO  --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s):  (http)
-- ::31.951  INFO  --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
-- ::31.951  INFO  --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.]
-- ::31.998  INFO  --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
-- ::31.998  INFO  --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in  ms
-- ::32.107  INFO  --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
-- ::32.185  INFO  --- [           main] o.s.s.c.ThreadPoolTaskScheduler          : Initializing ExecutorService 'taskScheduler'
I am Happy.
-- ::32.216  INFO  --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s):  (http) with context path ''
-- ::32.216  INFO  --- [           main] c.l.j.JavatestprojectApplication         : Started JavatestprojectApplication in 1.033 seconds (JVM running for 1.53)
I am Happy.
Hello.
I am Happy.
I am Happy.
Hello.
I am Happy.
I am Happy.
I am Happy.
Hello.
I am Happy.
I am Happy.
Hello.
I am Happy.
I am Happy.
I am Happy.
Hello.
I am Happy.