定时任务应用非常广泛，Java提供的现有解决方案有很多。

本次主要讲schedule、quartz、xxl-job、shedlock等相关的代码实践。

一、SpringBoot使用Schedule

核心代码:

@Componentpublic class ScheduleTask { private Logger logger = LoggerFactory.getLogger(ScheduleTask.class); @Scheduled(cron = "0/1 * * * * ? ") public void one() { logger.info("one:" + new Date()); } @Scheduled(cron = "0/1 * * * * ? ") public void two() { logger.info("two:" + new Date()); } @Scheduled(cron = "0/1 * * * * ? ") public void three() { logger.info("three:" + new Date()); }}

运行效果如下:

除此之外还可以这样实现，核心代码:

@PropertySource(value = { "classpath:task.properties",}, encoding = "utf-8")@Component("scheduleTask")public class ScheduleTask implements SchedulingConfigurer { @Value("${TEST_JOB_TASK_CRON}") private String cron; @Override public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) { scheduledTaskRegistrar.addTriggerTask(new Runnable() { @Override public void run() { System.out.println("执行任务:" + DateUtil.date()); } }, new Trigger() { @Override public Date nextExecutionTime(TriggerContext triggerContext) { return new CronTrigger(cron).nextExecutionTime(triggerContext); } }); } public void setCron(String cron) { this.cron = cron; }}

有朋友或许很疑惑，为什么要写这么一大堆，这个与前面的代码又有何区别呢？

区别是多线程并行。其实多线程并行也可以不用这么写，只需写一段核心配置类代码即可。

定时任务多线程配置类:

@Configurationpublic class ScheduleConfig implements SchedulingConfigurer { public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) { scheduledTaskRegistrar.setScheduler(Executors.newScheduledThreadPool(5)); }}

再次启动，查看效果，如下:

由此看出走不同的线程执行，不同的线程执行的好处是，如果某一个线程挂掉后，并不会阻塞导致其它定时任务无法执行。

另外如果要想并发执行，前面的配置可以不要，直接用SpringBoot提供的现成注解即可，核心代码如下:

@Component@EnableAsyncpublic class ScheduleAsyncTask { private Logger logger = LoggerFactory.getLogger(ScheduleAsyncTask.class); @Scheduled(cron = "0/1 * * * * ? ") @Async public void one() { logger.info("one Async:" + new Date()); } @Scheduled(cron = "0/1 * * * * ? ") @Async public void two() { logger.info("two Async:" + new Date()); } @Scheduled(cron = "0/1 * * * * ? ") @Async public void three() { logger.info("three Async:" + new Date()); }}

除此外，还有基于schedule动态定时任务(所谓动态只不过是指cron表达式放在对应的数据表里)，简单示例代码:

@Configurationpublic class DynamicScheduleTask implements SchedulingConfigurer { @Autowired @SuppressWarnings("all") CronMapper cronMapper; @Mapper public interface CronMapper { @Select("select cron from cron limit 1") public String getCron(); } /** * 执行定时任务. */ public void configureTasks(ScheduledTaskRegistrar taskRegistrar) { taskRegistrar.addTriggerTask( //1.添加任务内容(Runnable) () -> System.out.println("执行动态定时任务: " + LocalDateTime.now().toLocalTime()), //2.设置执行周期(Trigger) triggerContext -> { //2.1 从数据库获取执行周期 String cron = cronMapper.getCron(); //2.2 合法性校验. if (StringUtils.isEmpty(cron)) { // Omitted Code .. } //2.3 返回执行周期(Date) return new CronTrigger(cron).nextExecutionTime(triggerContext); } ); }}

核心配置文件(application.yml):

spring: datasource: url: jdbc:mysql://127.0.0.1:3306/test username: root password: 1234

SQL脚本:

DROP DATABASE IF EXISTS `test`;CREATE DATABASE `test`;USE `test`;DROP TABLE IF EXISTS `cron`;CREATE TABLE `cron` ( `cron_id` varchar(30) NOT NULL PRIMARY KEY, `cron` varchar(30) NOT NULL );INSERT INTO `cron` VALUES ('1', '0/5 * * * * ?');

运行效果如下:

二、SpringBoot使用Quartz

1.Maven依赖

<!--引入quartz定时框架--><dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-quartz</artifactId></dependency>

2.配置文件

spring: quartz: #相关属性配置 properties: org: quartz: scheduler: instanceName: clusteredScheduler instanceId: AUTO jobStore: class: org.quartz.impl.jdbcjobstore.JobStoreTX driverDelegateClass: org.quartz.impl.jdbcjobstore.StdJDBCDelegate tablePrefix: QRTZ_ isClustered: true clusterCheckinInterval: 10000 useProperties: false threadPool: class: org.quartz.simpl.SimpleThreadPool threadCount: 10 threadPriority: 5 threadsInheritContextClassLoaderOfInitializingThread: true #数据库方式 job-store-type: jdbc #初始化表结构 jdbc: initialize-schema: always datasource: url: jdbc:mysql://127.0.0.1:3306/test username: root password: 1234

3.启动类

@SpringBootApplication@EnableSchedulingpublic class BlogQuartzApplication { public static void main(String[] args) { SpringApplication.run(BlogQuartzApplication.class, args); }}

4.配置类

@Configurationpublic class QuartzConfiguration { // 使用jobDetail包装job @Bean public JobDetail myCronJobDetail() { return JobBuilder.newJob(CouponTimeOutJob.class).withIdentity("couponTimeOutJob").storeDurably().build(); } // 把jobDetail注册到Cron表达式的trigger上去 @Bean public Trigger CronJobTrigger() { CronScheduleBuilder cronScheduleBuilder = CronScheduleBuilder.cronSchedule("0/1 * * * * ?"); return TriggerBuilder.newTrigger() .forJob(myCronJobDetail()) .withIdentity("CouponTimeOutJobTrigger") .withSchedule(cronScheduleBuilder) .build(); }}

5.定时任务类

public class CouponTimeOutJob extends QuartzJobBean { @Override protected void executeInternal(JobExecutionContext jobExecutionContext) throws JobExecutionException { System.out.println("定时任务执行"); }}

6.启动成功不报错

(1)对应的数据库会生成定时任务相关的数据表

(2)控制台不断输出定时任务执行日志

三、SpringBoot使用xxl-job

之前写过一样的例子，如今简化了下。

关于xxl-job使用详情，可以参考我的这篇文章:

SpringBoot整合Xxl-Job

1.Maven依赖

<dependency> <groupId>com.xuxueli</groupId> <artifactId>xxl-job-core</artifactId> <version>2.2.0</version></dependency>

2.配置类

@Configurationpublic class XxlJobConfig { private Logger logger = LoggerFactory.getLogger(XxlJobConfig.class); @Value("${xxl.job.admin.addresses}") private String adminAddresses; @Value("${xxl.job.executor.appname}") private String appName; @Value("${xxl.job.executor.ip}") private String ip; @Value("${xxl.job.executor.port}") private int port; @Value("${xxl.job.accessToken}") private String accessToken; @Value("${xxl.job.executor.logpath}") private String logPath; @Value("${xxl.job.executor.logretentiondays}") private int logRetentionDays; @Bean(initMethod = "start", destroyMethod = "destroy") public XxlJobSpringExecutor xxlJobExecutor() { logger.info(">>>>>>>>>>> xxl-job config init."); XxlJobSpringExecutor xxlJobSpringExecutor = new XxlJobSpringExecutor(); xxlJobSpringExecutor.setAdminAddresses(adminAddresses); xxlJobSpringExecutor.setAppname(appName); xxlJobSpringExecutor.setIp(ip); xxlJobSpringExecutor.setPort(port); xxlJobSpringExecutor.setAccessToken(accessToken); xxlJobSpringExecutor.setLogPath(logPath); xxlJobSpringExecutor.setLogRetentionDays(logRetentionDays); return xxlJobSpringExecutor; }}

3.配置文件内容

# web portserver.port=8081# no web#spring.main.web-environment=false### xxl-job admin address list, such as "http://address" or "http://address01,http://address02"xxl.job.admin.addresses=http://127.0.0.1:8080/xxl-job-admin### xxl-job, access tokenxxl.job.accessToken=### xxl-job executor appnamexxl.job.executor.appname=blog-job-xxl-job### xxl-job executor registry-address: default use address to registry , otherwise use ip:port if address is nullxxl.job.executor.address=### xxl-job executor server-infoxxl.job.executor.ip=xxl.job.executor.port=8888### xxl-job executor log-pathxxl.job.executor.logpath=/data/applogs/xxl-job/jobhandler### xxl-job executor log-retention-daysxxl.job.executor.logretentiondays=30

4.定时任务类

@Componentpublic class XxlJobTaskExample { @XxlJob("blogJobHandler") public ReturnT<String> blogJobHandler(String param) throws Exception { System.out.println("执行"); XxlJobLogger.log("XXL-JOB, Hello World."); for (int i = 0; i < 5; i++) { XxlJobLogger.log("beat at:" + i); TimeUnit.SECONDS.sleep(2); } return ReturnT.SUCCESS; }}

5.执行效果

分别如下所示:

四、SpringBoot使用ShedLock

1.导入Maven依赖

<!-- 分布式定时任务锁 --> <!-- https://mvnrepository.com/artifact/net.javacrumbs.shedlock/shedlock-spring --> <dependency> <groupId>net.javacrumbs.shedlock</groupId> <artifactId>shedlock-spring</artifactId> <version>4.0.4</version> </dependency> <!-- 使用redis做分布式任务 --> <dependency> <groupId>net.javacrumbs.shedlock</groupId> <artifactId>shedlock-provider-redis-spring</artifactId> <version>2.5.0</version> </dependency> <!-- redis组件 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency>

2.编写配置类

@Configuration@EnableSchedulerLock(defaultLockAtMostFor = "PT30M")public class ShedLockConfig { @Bean public LockProvider lockProvider(RedisTemplate redisTemplate) { return new RedisLockProvider(redisTemplate.getConnectionFactory()); }}

3.编写具体的定时任务

@Componentpublic class TaskSchedule { /** * 每分钟执行一次 * [秒] [分] [小时] [日] [月] [周] [年] */ @Scheduled(cron = "1 * * * * ?") @SchedulerLock(name = "synchronousSchedule") public void SynchronousSchedule() { System.out.println("Start run schedule to synchronous data:" + new Date()); }}

4.编写启动类

@SpringBootApplication@EnableSchedulingpublic class ShedLockRedisApplication { public static void main(String[] args) { SpringApplication.run(ShedLockRedisApplication.class); }}

5.配置文件

server: tomcat: uri-encoding: UTF-8 max-threads: 1000 min-spare-threads: 30 port: 8083spring: redis: database: 0 host: localhost port: 6379 password: # 密码（默认为空） timeout: 6000ms # 连接超时时长（毫秒） jedis: pool: max-active: 1000 # 连接池最大连接数（使用负值表示没有限制） max-wait: -1ms # 连接池最大阻塞等待时间（使用负值表示没有限制） max-idle: 10 # 连接池中的最大空闲连接 min-idle: 5 # 连接池中的最小空闲连接

6.测试

我之所以用shedlock是因为确保在集群环境下各微服务的定时任务只执行一个，而不是全部都运行相同的定时任务。

本次测试效果如下:

本次代码例子已放至我的GitHub:https://github.com/developers-youcong/blog-job

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