ScheduledTasks

简介

在开发场景中，我们需要定时地发送一些短信、邮件之类的操作，也可能会定时地检查和监控一些标志、参数等，这时候我们就可以用springboot提供的定时器（Scheduled）

看完本章你将会知道

如何在指定时间里完成一件任务

配置文件

pom

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.boot</groupId>
    <artifactId>demo-task</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>demo-task</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>

项目结构

image.png

ScheduledTasks

package com.boot.task;

import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.text.SimpleDateFormat;
import java.util.Date;

@Slf4j
@Component
public class ScheduledTasks {


    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");

    @Scheduled(fixedRate = 5000)//每五秒运行一次
    public void reportCurrentTime() {
        log.info("时间： {}", dateFormat.format(new Date()));
    }


    /**
     * cron表达式，cron表达式
     * http://cron.qqe2.com/
     */
    @Scheduled(cron="*/10 * * * * *")//没10秒运行一次
    public void corn() {
        log.info("corn： {}", dateFormat.format(new Date()));
    }
}

DemoTaskApplication

@SpringBootApplication
@EnableScheduling
public class DemoTaskApplication {

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

run截图

image.png