实践：Spring Boot 实现定时任务的动态增删启停

约定不等于承诺〃 2021-09-01 02:07 345阅读 0赞

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作者：jessehua

链接：www.jianshu.com/p/0f68936393fd

我以为动态停启定时任务一般用quartz，没想到还可以通过ScheduledTaskRegistrar来拓展。但是分布式场景，建议还是用quartz吧！

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。

![format_png][]

定时任务列表页

![format_png 1][]

定时任务执行日志

添加执行定时任务的线程池配置类

@Configuration
    public class SchedulingConfig {
        @Bean
        public TaskScheduler taskScheduler() {
            ThreadPoolTaskScheduler taskScheduler = new ThreadPoolTaskScheduler();
            
            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;
    
        
        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。

@Component
    public 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

![format_png 2][]

定时任务数据库表设计

添加定时任务实体类

public class SysJobPO {
        
        private Integer jobId;
        
        private String beanName;
        
        private String methodName;
        
        private String methodParams;
        
        private String cronExpression;
        
        private Integer jobStatus;
        
        private String remark;
        
        private Date createTime;
        
        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

![format_png 3][]

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 {
        
        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);
    
        @Autowired
        private ISysJobRepository sysJobRepository;
    
        @Autowired
        private CronTaskRegistrar cronTaskRegistrar;
    
        @Override
        public void run(String... args) {
            
            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;
    
        @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);
        }
    }

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