利用spring自带的定时器实现动态定时器的增删改

ゝ一世哀愁。 2023-03-06 05:55 11阅读 0赞

> ## 福兮祸所伏，祸兮福所倚 ##

###  简单业务场景：项目启动的时候 启动多个定时器,实现定时器的增删改。（走高速） ###

实现CommandLineRunner接口  并标记为spring组件（@Component）
    
    @Component
    public class ScheduleConfig implements CommandLineRunner {
    
        private static final Logger LOG = LoggerFactory.getLogger(ScheduleConfig.class);
    
        @Autowired
        MeterTaskService meterTaskService;
    
        @Autowired
        private CronTaskRegistrar taskRegistrar;
    
        @Autowired
        DeviceService deviceService;
    
        @Override
        public void run(String... args) throws Exception {
            LOG.debug("进入ScheduleConfig.....");
            List<MeterTask> meterTasks = meterTaskService.findAllCron();
            if (meterTasks.size() > 0) {
                for (MeterTask meterTask : meterTasks) {
                    if (!meterTask.getIsSuccess()) {
                        // 每个定时器所对应的业务逻辑处理线程   
                        SchedulingRunnable task = new SchedulingRunnable(meterTask.getCron(), meterTask.getMeterId(), meterTaskService, deviceService);
                        // 将当前线程和标识以及cron表达式添加到CronTaskRegistrar中
                        taskRegistrar.addCronTask(meterTask.getMeterId(), task, meterTask.getCron());
                    }
                }
            }
        }
    }

看一下其中的taskRegistrar和SchedulingRunnable到底是什么鬼。

taskRegistrar

DisposableBean主要处理bean的  这里通过DisposableBean的destroy方法是销毁定时器
    
    @Component
    public class CronTaskRegistrar implements DisposableBean {
    
        // 线程安全map去存储定时器
        private final Map<Integer, ScheduledTask> scheduledTasks = new ConcurrentHashMap<>(16);
    
        @Autowired
        private TaskScheduler taskScheduler;
    
        // 添加定时器   cronId为定时器的唯一标识（根据你的业务去选择什么作为唯一标识）
        // task对应的线程   cronExpression为cron的表达式
        public void addCronTask(Integer cronId,Runnable task, String cronExpression) {
            addCronTask(cronId,new CronTask(task, cronExpression));
        }
    
        public void addCronTask(Integer cronId,CronTask cronTask) {
            if (cronTask != null) {
                if (this.scheduledTasks.containsKey(cronId)) {
                    removeCronTask(cronId);
                }
                this.scheduledTasks.put(cronId, scheduleCronTask(cronTask));
            }
        }
    
        // 移除某个定时器
        public void removeCronTask(Integer cronId) {
            ScheduledTask scheduledTask = this.scheduledTasks.remove(cronId);
            if (scheduledTask != null) {
                scheduledTask.cancel();
            }
        }
    
        // 核心代码   
        public ScheduledTask scheduleCronTask(CronTask cronTask) {
            ScheduledTask scheduledTask = new ScheduledTask();
            scheduledTask.future = this.taskScheduler.schedule(cronTask.getRunnable(), cronTask.getTrigger());
            return scheduledTask;
        }
    
    
        @Override
        public void destroy() throws Exception {
            for (ScheduledTask task : this.scheduledTasks.values()) {
                task.cancel();
            }
            this.scheduledTasks.clear();
        }
    }

SchedulingRunnable

/**
     * @author peanut
     */
    public class SchedulingRunnable implements Runnable{
    
        private static final Logger LOG = LoggerFactory.getLogger(SchedulingRunnable.class);
    
    
        private String cron;
    
        private Integer meterId;
    
        private MeterTaskService meterTaskService;
    
        private DeviceService deviceService;
    
        public SchedulingRunnable(String cron, Integer meterId, MeterTaskService meterTaskService, DeviceService deviceService) {
            this.cron = cron;
            this.meterId = meterId;
            this.meterTaskService = meterTaskService;
            this.deviceService = deviceService;
        }
    
        @SneakyThrows
        @Override
        public void run() {
            // 执行任务
            System.out.println(meterId + "的表达式是：" + cron);
            System.out.println("执行任务");
            // 清零
            try {
                deviceService.clear(meterId + "");
            } catch (ConnectionException e) {
                LOG.error("当前的异常是：{}" + e.getMessage());
                throw new ConnectionException("请检查端口链接");
            } catch (Exception e) {
                throw new Exception("请检查端口链接");
            }
    
            // 如果是单次的话  就修改状态
            MeterTask meterTask = meterTaskService.findByMeterId(meterId);
            if (MeterConstant.BIT_ZERO_FLAG.equals(meterTask.getType())) {
                meterTaskService.updateByMeterId(meterId);
            }
        }
    }

/**
     * @author peanut
     */
    public final class ScheduledTask {
        public volatile ScheduledFuture<?> future;
    
        /**
         * 取消定时任务
         */
        public void cancel() {
            ScheduledFuture<?> future = this.future;
            if (future != null) {
                future.cancel(true);
            }
        }
    }

> 代码很纯粹  很好理解   替换相关参数  可以直接拿去用 。

如果觉得有用的话  就可怜可怜小弟吧

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