Spring Boot文档阅读笔记-Scheduling Tasks

这篇博文将说明，如何一步一步完成Spring的任务调度功能。

主要是使用@Scheduled注解，完成每5秒打印当前时间。

首先在Maven中增加awaitility依赖包

<dependency>
  <groupId>org.awaitilitygroupId>
  <artifactId>awaitilityartifactId>
  <version>3.1.2version>
  <scope>testscope>
dependency>

整体Maven如下：

"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">
    <modelVersion>4.0.0modelVersion>
 
    <groupId>org.examplegroupId>
    <artifactId>SchedulingTasksartifactId>
    <version>1.0-SNAPSHOTversion>
 
    <dependencies>
 
        <dependency>
            <groupId>org.springframework.bootgroupId>
            <artifactId>spring-boot-starter-webartifactId>
            <version>2.1.10.RELEASEversion>
        dependency>
 
        <dependency>
            <groupId>org.awaitilitygroupId>
            <artifactId>awaitilityartifactId>
            <version>3.1.2version>
            <scope>testscope>
        dependency>
 
    dependencies>
 
project>

创建调度调度任务的类，ScheduleTasks.java

package cn.it1995.component;
 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
 
import java.text.SimpleDateFormat;
import java.util.Date;
 
@Component
public class ScheduledTasks {
 
    private static final Logger log = LoggerFactory.getLogger(ScheduledTasks.class);
 
    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
 
    @Scheduled(fixedDelay = 5000)
    public void reportCurrentTime(){
 
        log.info("The time is now {}", dateFormat.format(new Date()));
    }
}

@Scheduled注解说明了在合适调用，比如fixedDelay说明每多少毫秒调用一次。这里还有其他选项，比如使用corn，这里全称应该是crontab，也就是定时任务，如@Scheduled(cron="...")

package cn.it1995;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;
 
@SpringBootApplication
@EnableScheduling
public class Main {
 
    public static void main(String[] args){
 
        SpringApplication.run(Main.class, args);
    }
}

最后在@SpringBootApplication注解的地方，也就是main方法的地方，加上@EnableScheduling注解，这个注解的作用是使得后台任务调用执行被创建。

代码如下：Main.java

package cn.it1995;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableScheduling;
 
@SpringBootApplication
@EnableScheduling
public class Main {
 
    public static void main(String[] args){
 
        SpringApplication.run(Main.class, args);
    }
}

运行截图如下：

代码打包如下：

Java/SchedulingTasks at master · fengfanchen/Java · GitHub