SpringBoot定时任务自定义实现

SpringBoot定时任务自定义实现

1. 注解方式实现

暂不讨论(很容易,但很死板,无法动态添加或删除);

2. 自定义实现

- org.springframework.scheduling.annotation.EnableScheduling

该注解类接口的注释中有自定义实现SpringBoot的示例代码

@Configuration
@EnableScheduling
public class AppConfig implements SchedulingConfigurer {

    private ScheduledTaskRegistrar taskRegistrar;
    public ScheduledTaskRegistrar getTaskRegistrar() {
        return taskRegistrar;
    }

    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.setScheduler(taskScheduler());
        taskRegistrar.addTriggerTask(
            new Runnable() {
                public void run() {
                    myTask().work();
                }
            },
            new CustomTrigger()
        );
    }

    @Bean(destroyMethod="shutdown")
    public Executor taskScheduler() {
        return Executors.newScheduledThreadPool(42);
    }

    @Bean
    public MyTask myTask() {
        return new MyTask();
    }
}

该示例代码实现了添加自定义的任务,但和注解方式实现一样,程序运行后就马上加载了

- org.springframework.scheduling.config.ScheduledTaskRegistrar

Helper bean for registering tasks with a TaskScheduler, typically using cron expressions.
帮助bean向TaskScheduler注册任务，通常使用cron表达式。

初始化时可以使用下面的方法添加任务

    /**
     * Add a Runnable task to be triggered per the given {@link Trigger}.
     * @see TaskScheduler#scheduleAtFixedRate(Runnable, long)
     */
    public void addTriggerTask(Runnable task, Trigger trigger) {
        addTriggerTask(new TriggerTask(task, trigger));
    }

    /**
     * Add a {@code TriggerTask}.
     * @since 3.2
     * @see TaskScheduler#scheduleAtFixedRate(Runnable, long)
     */
    public void addTriggerTask(TriggerTask task) {
        if (this.triggerTasks == null) {
            this.triggerTasks = new ArrayList<>();
        }
        this.triggerTasks.add(task);
    }

    /**
     * Add a {@link Runnable} task to be triggered per the given cron {@code expression}.
     * <p>As of Spring Framework 5.2, this method will not register the task if the
     * {@code expression} is equal to {@link #CRON_DISABLED}.
     */
    public void addCronTask(Runnable task, String expression) {
        if (!CRON_DISABLED.equals(expression)) {
            addCronTask(new CronTask(task, expression));
        }
    }

    /**
     * Add a {@link CronTask}.
     * @since 3.2
     */
    public void addCronTask(CronTask task) {
        if (this.cronTasks == null) {
            this.cronTasks = new ArrayList<>();
        }
        this.cronTasks.add(task);
    }

    /**
     * Add a {@code Runnable} task to be triggered at the given fixed-rate interval.
     * @see TaskScheduler#scheduleAtFixedRate(Runnable, long)
     */
    public void addFixedRateTask(Runnable task, long interval) {
        addFixedRateTask(new IntervalTask(task, interval, 0));
    }

    /**
     * Add a fixed-rate {@link IntervalTask}.
     * @since 3.2
     * @see TaskScheduler#scheduleAtFixedRate(Runnable, long)
     */
    public void addFixedRateTask(IntervalTask task) {
        if (this.fixedRateTasks == null) {
            this.fixedRateTasks = new ArrayList<>();
        }
        this.fixedRateTasks.add(task);
    }

    /**
     * Add a Runnable task to be triggered with the given fixed delay.
     * @see TaskScheduler#scheduleWithFixedDelay(Runnable, long)
     */
    public void addFixedDelayTask(Runnable task, long delay) {
        addFixedDelayTask(new IntervalTask(task, delay, 0));
    }

    /**
     * Add a fixed-delay {@link IntervalTask}.
     * @since 3.2
     * @see TaskScheduler#scheduleWithFixedDelay(Runnable, long)
     */
    public void addFixedDelayTask(IntervalTask task) {
        if (this.fixedDelayTasks == null) {
            this.fixedDelayTasks = new ArrayList<>();
        }
        this.fixedDelayTasks.add(task);
    }

运行中添加任务使用

    /**
     * Schedule the specified trigger task, either right away if possible
     * or on initialization of the scheduler.
     * @return a handle to the scheduled task, allowing to cancel it
     * @since 4.3
     */
    @Nullable
    public ScheduledTask scheduleTriggerTask(TriggerTask task) {
        ...
    }

    /**
     * Schedule the specified cron task, either right away if possible
     * or on initialization of the scheduler.
     * @return a handle to the scheduled task, allowing to cancel it
     * (or {@code null} if processing a previously registered task)
     * @since 4.3
     */
    @Nullable
    public ScheduledTask scheduleCronTask(CronTask task) {
        ...
    }

    /**
     * Schedule the specified fixed-rate task, either right away if possible
     * or on initialization of the scheduler.
     * @return a handle to the scheduled task, allowing to cancel it
     * (or {@code null} if processing a previously registered task)
     * @since 5.0.2
     */
    @Nullable
    public ScheduledTask scheduleFixedRateTask(FixedRateTask task) {
        ...
    }

    /**
     * Schedule the specified fixed-delay task, either right away if possible
     * or on initialization of the scheduler.
     * @return a handle to the scheduled task, allowing to cancel it
     * (or {@code null} if processing a previously registered task)
     * @since 4.3
     * @deprecated as of 5.0.2, in favor of {@link #scheduleFixedDelayTask(FixedDelayTask)}
     */

    /**
     * Schedule the specified fixed-delay task, either right away if possible
     * or on initialization of the scheduler.
     * @return a handle to the scheduled task, allowing to cancel it
     * (or {@code null} if processing a previously registered task)
     * @since 5.0.2
     */
    @Nullable
    public ScheduledTask scheduleFixedDelayTask(FixedDelayTask task) {
        ...
    }

运行过程中使用add方法添加的任务不会执行,如果强行使用方法:org.springframework.scheduling.config.ScheduledTaskRegistrar.afterPropertiesSet
之前运行的任务会再次被调度执行,导致多个线程同时在执行同一个任务的混乱情况

- 示例

@RestController
@RequestMapping("/task")
public class TestTaskApi {
    private Logger log = LoggerFactory.getLogger(this.getClass());

    @Autowired
    AppConfig taskConfig;

    @RequestMapping("/add")
    public String add(String cron){
        ScheduledTaskRegistrar taskRegistrar = taskConfig.getTaskRegistrar();
        taskRegistrar.scheduleCronTask(new CronTask(() -> {
            log.error("执行[" + cron + "]");
        }, cron));
        return cron;
    }


}

cron表达式

A cron-like expression, extending the usual UN*X definition to include triggers on the second, minute, > > > hour, day of month, month, and day of week.
For example, "0 * * * * MON-FRI" means once per minute on weekdays (at the top of the minute - the 0th > second).
The fields read from left to right are interpreted as follows.
second
minute
hour
day of month
month
day of week
The special value "-" indicates a disabled cron trigger, primarily meant for externally specified values > > > > resolved by a ${...} placeholder.