Spring Boot 实现定时任务的动态增删启停
责编：Java就该这么学 | 来源：https://mp.weixin.qq.com/s/QJ4rgCefOjwwHdb7MZzA3w
在spring boot项目中，可以通过@EnableScheduling注解和@Scheduled注解实现定时任务，也可以通过SchedulingConfigurer接口来实现定时任务。但是这两种方式不能动态添加、删除、启动、停止任务。
要实现动态增删启停定时任务功能，比较广泛的做法是集成Quartz框架。但是本人的开发原则是：在满足项目需求的情况下，尽量少的依赖其它框架，避免项目过于臃肿和复杂。
查看spring-context这个jar包中org.springframework.scheduling.ScheduledTaskRegistrar这个类的源代码，发现可以通过改造这个类就能实现动态增删启停定时任务功能。
定时任务执行日志
添加执行定时任务的线程池配置类
@Configurationpublic class SchedulingConfig { @Bean public TaskScheduler taskScheduler() { ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler(); // 定时任务执行线程池核心线程数 taskScheduler.setPoolSize(4); taskScheduler.setRemoveOnCancelPolicy(true); taskScheduler.setThreadNamePrefix("TaskSchedulerThreadPool-"); return taskScheduler; }}添加ScheduledFuture的包装类。ScheduledFuture是ScheduledExecutorService定时任务线程池的执行结果。
public final class ScheduledTask {
volatile ScheduledFuture<?> future;
/** * 取消定时任务 */ public void cancel() { ScheduledFuture<?> future = this.future; if (future != null) { future.cancel(true); } }}添加Runnable接口实现类，被定时任务线程池调用，用来执行指定bean里面的方法。
public class SchedulingRunnable implements Runnable {
private static final Logger logger = LoggerFactory.getLogger(SchedulingRunnable.class);
private String beanName;
private String methodName;
private String params;
public SchedulingRunnable(String beanName, String methodName) { this(beanName, methodName, null); }
public SchedulingRunnable(String beanName, String methodName, String params) { this.beanName = beanName; this.methodName = methodName; this.params = params; }
@Override public void run() { logger.info("定时任务开始执行 - bean：{}，方法：{}，参数：{}", beanName, methodName, params); long startTime = System.currentTimeMillis();
try { Object target = SpringContextUtils.getBean(beanName);
Method method = null; if (StringUtils.isNotEmpty(params)) { method = target.getClass().getDeclaredMethod(methodName, String.class); } else { method = target.getClass().getDeclaredMethod(methodName); }
ReflectionUtils.makeAccessible(method); if (StringUtils.isNotEmpty(params)) { method.invoke(target, params); } else { method.invoke(target); } } catch (Exception ex) { logger.error(String.format("定时任务执行异常 - bean：%s，方法：%s，参数：%s ", beanName, methodName, params), ex); }
long times = System.currentTimeMillis() - startTime; logger.info("定时任务执行结束 - bean：{}，方法：{}，参数：{}，耗时：{} 毫秒", beanName, methodName, params, times); }
@Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; SchedulingRunnable that = (SchedulingRunnable) o; if (params == null) { return beanName.equals(that.beanName) && methodName.equals(that.methodName) && that.params == null; }
return beanName.equals(that.beanName) && methodName.equals(that.methodName) && params.equals(that.params); }
@Override public int hashCode() { if (params == null) { return Objects.hash(beanName, methodName); }
return Objects.hash(beanName, methodName, params); }}添加定时任务注册类，用来增加、删除定时任务。
@Componentpublic class CronTaskRegistrar implements DisposableBean {
private final Map<Runnable, ScheduledTask> scheduledTasks = new ConcurrentHashMap<>(16);
@Autowired private TaskScheduler taskScheduler;
public TaskScheduler getScheduler() { return this.taskScheduler; }
public void addCronTask(Runnable task, String cronExpression) { addCronTask(new CronTask(task, cronExpression)); }
public void addCronTask(CronTask cronTask) { if (cronTask != null) { Runnable task = cronTask.getRunnable(); if (this.scheduledTasks.containsKey(task)) { removeCronTask(task); }
this.scheduledTasks.put(task, scheduleCronTask(cronTask)); } }
public void removeCronTask(Runnable task) { ScheduledTask scheduledTask = this.scheduledTasks.remove(task); if (scheduledTask != null) scheduledTask.cancel(); }
public ScheduledTask scheduleCronTask(CronTask cronTask) { ScheduledTask scheduledTask = new ScheduledTask(); scheduledTask.future = this.taskScheduler.schedule(cronTask.getRunnable(), cronTask.getTrigger());
return scheduledTask; }
@Override public void destroy() { for (ScheduledTask task : this.scheduledTasks.values()) { task.cancel(); }
this.scheduledTasks.clear(); }}
添加定时任务示例类
@Component("demoTask")public class DemoTask { public void taskWithParams(String params) { System.out.println("执行有参示例任务：" + params); }
public void taskNoParams() { System.out.println("执行无参示例任务"); }}定时任务数据库表设计
定时任务数据库表设计
添加定时任务实体类
public class SysJobPO { /** * 任务ID */ private Integer jobId; /** * bean名称 */ private String beanName; /** * 方法名称 */ private String methodName; /** * 方法参数 */ private String methodParams; /** * cron表达式 */ private String cronExpression; /** * 状态（1正常 0暂停） */ private Integer jobStatus; /** * 备注 */ private String remark; /** * 创建时间 */ private Date createTime; /** * 更新时间 */ private Date updateTime;
public Integer getJobId() { return jobId; }
public void setJobId(Integer jobId) { this.jobId = jobId; }
public String getBeanName() { return beanName; }
public void setBeanName(String beanName) { this.beanName = beanName; }
public String getMethodName() { return methodName; }
public void setMethodName(String methodName) { this.methodName = methodName; }
public String getMethodParams() { return methodParams; }
public void setMethodParams(String methodParams) { this.methodParams = methodParams; }
public String getCronExpression() { return cronExpression; }
public void setCronExpression(String cronExpression) { this.cronExpression = cronExpression; }
public Integer getJobStatus() { return jobStatus; }
public void setJobStatus(Integer jobStatus) { this.jobStatus = jobStatus; }
public String getRemark() { return remark; }
public void setRemark(String remark) { this.remark = remark; }
public Date getCreateTime() { return createTime; }
public void setCreateTime(Date createTime) { this.createTime = createTime; }
public Date getUpdateTime() { return updateTime; }
public void setUpdateTime(Date updateTime) { this.updateTime = updateTime; }
}新增定时任务
新增定时任务
boolean success = sysJobRepository.addSysJob(sysJob);if (!success) return OperationResUtils.fail("新增失败");else { if (sysJob.getJobStatus().equals(SysJobStatus.NORMAL.ordinal())) { SchedulingRunnable task = new SchedulingRunnable(sysJob.getBeanName(), sysJob.getMethodName(), sysJob.getMethodParams()); cronTaskRegistrar.addCronTask(task, sysJob.getCronExpression()); }}
return OperationResUtils.success();修改定时任务，先移除原来的任务，再启动新任务
boolean success = sysJobRepository.editSysJob(sysJob);if (!success) return OperationResUtils.fail("编辑失败");else { //先移除再添加 if (existedSysJob.getJobStatus().equals(SysJobStatus.NORMAL.ordinal())) { SchedulingRunnable task = new SchedulingRunnable(existedSysJob.getBeanName(), existedSysJob.getMethodName(), existedSysJob.getMethodParams()); cronTaskRegistrar.removeCronTask(task); }
if (sysJob.getJobStatus().equals(SysJobStatus.NORMAL.ordinal())) { SchedulingRunnable task = new SchedulingRunnable(sysJob.getBeanName(), sysJob.getMethodName(), sysJob.getMethodParams()); cronTaskRegistrar.addCronTask(task, sysJob.getCronExpression()); }}
return OperationResUtils.success();删除定时任务
boolean success = sysJobRepository.deleteSysJobById(req.getJobId());if (!success) return OperationResUtils.fail("删除失败");else{ if (existedSysJob.getJobStatus().equals(SysJobStatus.NORMAL.ordinal())) { SchedulingRunnable task = new SchedulingRunnable(existedSysJob.getBeanName(), existedSysJob.getMethodName(), existedSysJob.getMethodParams()); cronTaskRegistrar.removeCronTask(task); }}
return OperationResUtils.success();定时任务启动/停止状态切换
if (existedSysJob.getJobStatus().equals(SysJobStatus.NORMAL.ordinal())) { SchedulingRunnable task = new SchedulingRunnable(existedSysJob.getBeanName(), existedSysJob.getMethodName(), existedSysJob.getMethodParams()); cronTaskRegistrar.addCronTask(task, existedSysJob.getCronExpression());} else { SchedulingRunnable task = new SchedulingRunnable(existedSysJob.getBeanName(), existedSysJob.getMethodName(), existedSysJob.getMethodParams()); cronTaskRegistrar.removeCronTask(task);}添加实现了CommandLineRunner接口的SysJobRunner类，当spring boot项目启动完成后，加载数据库里状态为正常的定时任务。
@Servicepublic class SysJobRunner implements CommandLineRunner {
private static final Logger logger = LoggerFactory.getLogger(SysJobRunner.class);
@Autowired private ISysJobRepository sysJobRepository;
@Autowired private CronTaskRegistrar cronTaskRegistrar;
@Override public void run(String... args) { // 初始加载数据库里状态为正常的定时任务 List<SysJobPO> jobList = sysJobRepository.getSysJobListByStatus(SysJobStatus.NORMAL.ordinal()); if (CollectionUtils.isNotEmpty(jobList)) { for (SysJobPO job : jobList) { SchedulingRunnable task = new SchedulingRunnable(job.getBeanName(), job.getMethodName(), job.getMethodParams()); cronTaskRegistrar.addCronTask(task, job.getCronExpression()); }
logger.info("定时任务已加载完毕..."); } }}工具类SpringContextUtils，用来从spring容器里获取bean
@Componentpublic class SpringContextUtils implements ApplicationContextAware {
private static ApplicationContext applicationContext;
@Override public void setApplicationContext(ApplicationContext applicationContext) throws BeansException { SpringContextUtils.applicationContext = applicationContext; }
public static Object getBean(String name) { return applicationContext.getBean(name); }
public static <T> T getBean(Class<T> requiredType) { return applicationContext.getBean(requiredType); }
public static <T> T getBean(String name, Class<T> requiredType) { return applicationContext.getBean(name, requiredType); }
public static boolean containsBean(String name) { return applicationContext.containsBean(name); }
public static boolean isSingleton(String name) { return applicationContext.isSingleton(name); }
public static Class<? extends Object> getType(String name) { return applicationContext.getType(name); }}欢迎有需要的同学试试，如果本文对您有帮助，也请帮忙点个 赞 + 在看 啦！❤️在 GitHub猿 还有更多优质项目系统学习资源，欢迎分享给其他同学吧！
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