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来源：jianshu.com/p/0f68936393fd

• 添加执行定时任务的线程池配置类

• 添加定时任务示例类

• 定时任务数据库表设计

• 添加定时任务实体类

• 新增定时任务

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。

添加执行定时任务的线程池配置类

@Configuration
public class SchedulingConfig {@Beanpublic 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;}@Overridepublic 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);}@Overridepublic 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);}@Overridepublic 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。

@Component
public class CronTaskRegistrar implements DisposableBean {private final Map<Runnable, ScheduledTask> scheduledTasks = new ConcurrentHashMap<>(16);@Autowiredprivate 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;}@Overridepublic void destroy() {for (ScheduledTask task : this.scheduledTasks.values()) {task.cancel();}this.scheduledTasks.clear();}
}

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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");}
}

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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

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。

@Service
public class SysJobRunner implements CommandLineRunner {private static final Logger logger = LoggerFactory.getLogger(SysJobRunner.class);@Autowiredprivate ISysJobRepository sysJobRepository;@Autowiredprivate CronTaskRegistrar cronTaskRegistrar;@Overridepublic 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

@Component
public class SpringContextUtils implements ApplicationContextAware {private static ApplicationContext applicationContext;@Overridepublic 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);}
}

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