怎么在SpringBoot项目中简单使用定时任务，不过由于要借助cron表达式且都提前定义好放在配置文件里，不能在项目运行中动态修改任务执行时间，实在不太灵活。
经过网上搜索学习后，特此记录如何在SpringBoot项目中实现动态定时任务。
因为只是一个demo，所以只引入了需要的依赖：
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-log4j2</artifactId> <optional>true</optional> </dependency> <!-- spring boot 2.3版本后，如果需要使用校验，需手动导入validation包--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-validation</artifactId> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> </dependencies>
启动类：
package com.wl.demo; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.scheduling.annotation.EnableScheduling; @EnableScheduling @SpringBootApplication public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); System.out.println("(*^▽^*)启动成功!!!(〃'▽'〃)"); } }
配置文件application.yml，只定义了服务端口：
server: port: 8089
定时任务执行时间配置文件：task-config.ini:
printTime.cron=0/10 * * * * ?
定时任务执行类：
package com.wl.demo.task; import lombok.Data; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Value; import org.springframework.context.annotation.PropertySource; import org.springframework.scheduling.Trigger; import org.springframework.scheduling.TriggerContext; import org.springframework.scheduling.annotation.SchedulingConfigurer; import org.springframework.scheduling.config.ScheduledTaskRegistrar; import org.springframework.scheduling.support.CronTrigger; import org.springframework.stereotype.Component; import java.time.LocalDateTime; import java.util.Date; @Data @Slf4j @Component @PropertySource("classpath:/task-config.ini") public class ScheduleTask implements SchedulingConfigurer { @Value("${printTime.cron}") private String cron; @Override public void configureTasks(ScheduledTaskRegistrar taskRegistrar) { // 动态使用cron表达式设置循环间隔 taskRegistrar.addTriggerTask(new Runnable() { @Override public void run() { log.info("Current time： {}", LocalDateTime.now()); } }, new Trigger() { @Override public Date nextExecutionTime(TriggerContext triggerContext) { // 使用CronTrigger触发器，可动态修改cron表达式来操作循环规则 CronTrigger cronTrigger = new CronTrigger(cron); Date nextExecutionTime = cronTrigger.nextExecutionTime(triggerContext); return nextExecutionTime; } }); } }
编写一个接口，使得可以通过调用接口动态修改该定时任务的执行时间：
package com.wl.demo.controller; import com.wl.demo.task.ScheduleTask; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @Slf4j @RestController @RequestMapping("/test") public class TestController { private final ScheduleTask scheduleTask; @Autowired public TestController(ScheduleTask scheduleTask) { this.scheduleTask = scheduleTask; } @GetMapping("/updateCron") public String updateCron(String cron) { log.info("new cron :{}", cron); scheduleTask.setCron(cron); return "ok"; } }
启动项目，可以看到任务每10秒执行一次：
访问接口，传入请求参数cron表达式，将定时任务修改为15秒执行一次：
可以看到任务变成了15秒执行一次
除了上面的借助cron表达式的方法，还有另一种触发器，区别于CronTrigger触发器，该触发器可随意设置循环间隔时间，不像cron表达式只能定义小于等于间隔59秒。
package com.wl.demo.task; import lombok.Data; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Value; import org.springframework.context.annotation.PropertySource; import org.springframework.scheduling.Trigger; import org.springframework.scheduling.TriggerContext; import org.springframework.scheduling.annotation.SchedulingConfigurer; import org.springframework.scheduling.config.ScheduledTaskRegistrar; import org.springframework.scheduling.support.CronTrigger; import org.springframework.scheduling.support.PeriodicTrigger; import org.springframework.stereotype.Component; import java.time.LocalDateTime; import java.util.Date; @Data @Slf4j @Component @PropertySource("classpath:/task-config.ini") public class ScheduleTask implements SchedulingConfigurer { @Value("${printTime.cron}") private String cron; private Long timer = 10000L; @Override public void configureTasks(ScheduledTaskRegistrar taskRegistrar) { // 动态使用cron表达式设置循环间隔 taskRegistrar.addTriggerTask(new Runnable() { @Override public void run() { log.info("Current time： {}", LocalDateTime.now()); } }, new Trigger() { @Override public Date nextExecutionTime(TriggerContext triggerContext) { // 使用CronTrigger触发器，可动态修改cron表达式来操作循环规则 // CronTrigger cronTrigger = new CronTrigger(cron); // Date nextExecutionTime = cronTrigger.nextExecutionTime(triggerContext); // 使用不同的触发器，为设置循环时间的关键，区别于CronTrigger触发器，该触发器可随意设置循环间隔时间，单位为毫秒 PeriodicTrigger periodicTrigger = new PeriodicTrigger(timer); Date nextExecutionTime = periodicTrigger.nextExecutionTime(triggerContext); return nextExecutionTime; } }); } }
增加一个修改时间的接口：
package com.wl.demo.controller; import com.wl.demo.task.ScheduleTask; import lombok.extern.slf4j.Slf4j; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @Slf4j @RestController @RequestMapping("/test") public class TestController { private final ScheduleTask scheduleTask; @Autowired public TestController(ScheduleTask scheduleTask) { this.scheduleTask = scheduleTask; } @GetMapping("/updateCron") public String updateCron(String cron) { log.info("new cron :{}", cron); scheduleTask.setCron(cron); return "ok"; } @GetMapping("/updateTimer") public String updateTimer(Long timer) { log.info("new timer :{}", timer); scheduleTask.setTimer(timer); return "ok"; } }
测试结果：
