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