Spring任务调度Scheduling Tasks

港控/mmm° 2022-07-17 03:27 219阅读 0赞

## 注解方式 ##

**第一步、创建maven工程，引入依赖**

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.0.RELEASE</version>
    </parent>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

相关注解存在于spring-context-xxx.jar包中，依赖可以按需引入

**第二步、创建调度任务**  
@Scheduled注解的方法不能有返回值，并且不能有形参

package hello;
    
    import java.text.SimpleDateFormat;
    import java.util.Date;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.scheduling.annotation.Scheduled;
    import org.springframework.stereotype.Component;
    
    @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()));
    	}
    }

**第三步、SpringBoot方式启动容器、测试**  
在@Configuration注解的类上添加\*\*@EnableScheduling\*\*注解，为@Scheduled提供调度支持

package hello;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.scheduling.annotation.EnableScheduling;
    
    @SpringBootApplication
    @EnableScheduling
    public class Application {
    
    public static void main(String[] args) throws Exception {
            SpringApplication.run(Application.class);
    }
    }

或者在spring配置文件中加入以下代码来启用任务调度

<task:annotation-driven/>

注：@SpringBootApplication注解是非常便利偷懒的方式，它包含了@Configuration、@EnableAutoConfiguration、 @EnableWebMvc、@ComponentScan的功能

运行结果：  
2016-08-26 16:23:06.316 INFO 37376 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 16:23:06  
2016-08-26 16:23:11.316 INFO 37376 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 16:23:11  
2016-08-26 16:23:16.316 INFO 37376 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 16:23:16

**@Scheduled Annotation**  
fixdDelay：以指定时间间隔调度（以方法执行结束时间为准）

@Scheduled(fixedDelay=5000)public void doSomething() {
        // something that should execute periodically
    }

fixedRate：以指定时间间隔调度任务（以方法执行开始时间为准）

@Scheduled(fixedRate=5000)public void doSomething() {
        // something that should execute periodically
    }

initialDelay：指定延迟后开始调度任务

@Scheduled(initialDelay=1000, fixedRate=5000)public void doSomething() {
        // something that should execute periodically
    }

cron表达式： 如下表示只在工作日每5秒执行一次

@Scheduled(cron="*/5 * * * * MON-FRI")public void doSomething() {
        // something that should execute on weekdays only
    }

fixdDelay和fixedRate的区别通过下面代码便能理解

fixedRate：

@Scheduled(fixedRate = 3000)
    public void reportCurrentTime() throws InterruptedException {
    	log.info("Sleep a while");
    	Thread.sleep(2000l);
    	log.info("The time is now {}", dateFormat.format(new Date()));
    }

运行结果：  
016-08-26 17:06:30.589 INFO 24844 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 17:06:30  
2016-08-26 17:06:31.589 INFO 24844 — \[pool-1-thread-1\] hello.ScheduledTasks : Sleep a while  
2016-08-26 17:06:33.589 INFO 24844 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 17:06:33  
2016-08-26 17:06:34.589 INFO 24844 — \[pool-1-thread-1\] hello.ScheduledTasks : Sleep a while  
2016-08-26 17:06:36.590 INFO 24844 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 17:06:36

fixdDelay：

@Scheduled(fixedDelay = 3000)
    public void reportCurrentTime() throws InterruptedException {
    	log.info("Sleep a while");
    	Thread.sleep(2000l);
    	log.info("The time is now {}", dateFormat.format(new Date()));
    }

运行结果：  
2016-08-26 17:08:24.959 INFO 9996 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 17:08:24  
2016-08-26 17:08:27.963 INFO 9996 — \[pool-1-thread-1\] hello.ScheduledTasks : Sleep a while  
2016-08-26 17:08:29.964 INFO 9996 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 17:08:29  
2016-08-26 17:08:32.964 INFO 9996 — \[pool-1-thread-1\] hello.ScheduledTasks : Sleep a while  
2016-08-26 17:08:34.964 INFO 9996 — \[pool-1-thread-1\] hello.ScheduledTasks : The time is now 17:08:34

## XML方式 ##

**第一步、创建调度任务**

package hello;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.stereotype.Component;
    import java.text.SimpleDateFormat;
    import java.util.Date;
    
    @Component("scheduledTasks2")
    public class ScheduledTasks2 {
    private static final Logger log = LoggerFactory.getLogger(ScheduledTasks2.class);
    
    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
    
    public void reportCurrentTime() throws InterruptedException {
    	log.info("The time is now {}", dateFormat.format(new Date()));
    	}
    }

**第二步、xml配置**  
创建任务调度配置文件spring-task.xml

<?xml version="1.0" encoding="UTF-8"?>
    <beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:task="http://www.springframework.org/schema/task"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    
    
    <context:component-scan base-package="hello">
        </context:component-scan>
    
    <task:scheduler id="myScheduler" pool-size="5"/>
    
    <task:scheduled-tasks scheduler="myScheduler">
            <task:scheduled ref="scheduledTasks2" method="reportCurrentTime" fixed-delay="5000" initial-delay="1000"/>
    
    </task:scheduled-tasks>
    </beans>

**第三步、SpringBoot方式启动容器、测试**

package hello;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.ImportResource;
    
    @SpringBootApplication
    @ImportResource(locations={"classpath:spring-task.xml"})
    public class Application {
    
    public static void main(String[] args) throws Exception {
            SpringApplication.run(Application.class);
    }
    }

运行结果：  
2016-08-29 11:47:11.615 INFO 26656 — \[ myScheduler-1\] hello.ScheduledTasks2 : The time is now 11:47:11  
2016-08-29 11:47:16.621 INFO 26656 — \[ myScheduler-1\] hello.ScheduledTasks2 : The time is now 11:47:16  
2016-08-29 11:47:21.622 INFO 26656 — \[ myScheduler-2\] hello.ScheduledTasks2 : The time is now 11:47:21

注：xml配置文件中

<context:component-scan base-package="hello">
    </context:component-scan>

其实多余了，因为SpringBootApplication已经包含bean扫描的功能

参考  
http://spring.io/guides/gs/scheduling-tasks/  
http://docs.spring.io/spring/docs/current/spring-framework-reference/html/scheduling.html