Springboot中使用Scheduled做定时任务

在开发中，定时任务是常见的功能，在spring boot 下开发定时任务其实很简单，具体代码如下：

1、配置依赖包pom.xml

由于默认的maven仓库经常访问不了，这里采用了阿里云的maven仓库镜像。

<?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.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>spring-boot-scheduled</name>
    <description>Demo project for Spring Boot</description>

    <!-- 阿里云maven仓库 -->
    <repositories>
        <repository>
            <id>public</id>
            <name>aliyun nexus</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>public</id>
            <name>aliyun nexus</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.5.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-web</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>

2、定制任务场景

定时任务实现，提供固定周期、固定周期延迟间隔和制定时间点执行等场景。采用@Scheduled注解进行标注。

ExampleTimer.java

package com.example;

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

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

@Component
public class ExampleTimer {
     SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");

        @Scheduled(fixedRate = 10000)
        public void timerRate() {
            System.out.println(dateFormat.format(new Date()));
        }

        //第一次延迟1秒执行，当执行完后2秒再执行
        @Scheduled(initialDelay = 1000, fixedDelay = 2000)
        public void timerInit() {
            System.out.println("init : "+dateFormat.format(new Date()));
        }

        //每天20点16分50秒时执行
        @Scheduled(cron = "50 16 20 * * ?")
        public void timerCron() {
            System.out.println("current time : "+ dateFormat.format(new Date()));
        }
}

3、启动应用程序

启动程序，需要增加@EnableScheduling注解.

SpringBootScheduledApplication.java

package com.example;

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

@SpringBootApplication
@EnableScheduling
public class SpringBootScheduledApplication {

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

4、输出结果

20:16:27
init : 20:16:28
init : 20:16:30
init : 20:16:32
init : 20:16:34
init : 20:16:36
20:16:37
init : 20:16:38
init : 20:16:40
init : 20:16:42
init : 20:16:44
init : 20:16:46
20:16:47
init : 20:16:48
current time : 20:16:50
init : 20:16:50
init : 20:16:52
init : 20:16:54