SpringBoot动态定时任务

其实SchedulingConfigurer实现方法很简单，只需要实现SchedulingConfigurer并重写configureTasks方法，在启动类必须加上@EnableScheduling注解即可。

@Configuration
@EnableScheduling
@Slf4j
public class RuleTask implements SchedulingConfigurer {

    private volatile ScheduledTaskRegistrar registrar;
    private ConcurrentHashMap<Long, ScheduledFuture<?>> scheduledFutures = new ConcurrentHashMap<>();
    private ConcurrentHashMap<Long, CronTask> cronTasks = new ConcurrentHashMap<>();

    @Override
    public void configureTasks(ScheduledTaskRegistrar registrar) {
        registrar.setScheduler(Executors.newScheduledThreadPool(30));
        this.registrar = registrar;
    }

    /**
     * 刷新任务
     * cronList是数据库查出来的定时任务列表
     * @param ruleList
     */
    public void refresh(List<WarCron> cronList) {
        //取消已经删除的任务
        Set<Long> cronIds = scheduledFutures.keySet();
        for (Long cronId : cronIds) {
            if (!exists(cronList, cronId)) {
                scheduledFutures.get(cronId).cancel(false);
            }
        }
        if (cronList != null) {
            for (WarCron warCron : cronList) {
                String expression = warCron.getCron();
                //定时任务已存在且表达式未发生变化时跳过
                if (scheduledFutures.containsKey(warCron.getCronId()) && cronTasks.get(warCron.getCronId()).getExpression().equals(expression)) {
                    continue;
                }
                //如果执行时间发生了变化，则取消当前的定时任务
                if (scheduledFutures.containsKey(warCron.getCronId())) {
                    scheduledFutures.get(warCron.getCronId()).cancel(false);
                    scheduledFutures.remove(warCron.getCronId());
                    cronTasks.remove(warCron.getCronId());
                }
                CronTask task = new CronTask(
                        new Runnable() {
                            @Override
                            public void run() {
                                System.out.println("------------定时任务--------------");
                            }
                        }, warCron.getCron()
                );
                ScheduledFuture<?> future = registrar.getScheduler().schedule(task.getRunnable(), task.getTrigger());
                cronTasks.put(warCron.getCronId(), task);
                scheduledFutures.put(warCron.getCronId(), future);
            }
        }
    }

   /**
     * 判断是否有该任务
     *
     * @param warCronList
     * @param cronId
     * @return
     */
    private boolean exists(List<WarCron> warCronList, Long cronId) {
        for (WarCron warCron : warCronList) {
            if (cronId.equals(warCron.getCronId())) {
                return true;
            }
        }
        return false;
    }
}

每次新增编辑删除数据库中的任务时都需刷新下任务 以达到任务的动态变化
启动boot时也需执行refresh方法;

/**
 * @Author: pandar
 * @Date: 2021/3/12 0012 上午 11:57
 * @Description:  项目启动后刷新定时任务
 */
@Component
public class ApplicationRunnerConfig implements ApplicationRunner {

    @Autowired
    private RuleTask ruleTask;
    @Autowired
    private WarCronService warCronService;

    @Override
    public void run(ApplicationArguments args) throws Exception {
        List<WarCron> warCronList = warCronService.selectWarCronAll();
        ruleTask.refresh(ruleList);
    }
}

数据库表结构

数据库.png