动态可改变时间间隔的定时任务

@Scheduled 和SchedulingConfigurer接口的区别

@Schedule注解的一个缺点就是其定时时间不能动态更改，它适用于具有固定任务周期的任务，若要修改任务执行周期，只能走“停服务→修改任务执行周期→重启服务”这条路。

而基于 SchedulingConfigurer 接口方式可以做。

SchedulingConfigurer 接口可以实现在@Configuration 类上，同时不要忘了，还需要@EnableScheduling 注解的支持。

使用方法

1、创建数据库

CREATE TABLE `trip_job_lock`  (
  `job_name` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL COMMENT '定时任务名称',
  `is_lock` char(1) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '是否开启任务 1-开启，0-关闭',
  `job_cron` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '定时任务执行时间间隔',
  `job_desc` varchar(50) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL COMMENT '定时任务中午描述',
  PRIMARY KEY (`job_name`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '定时任务配置表' ROW_FORMAT = Dynamic;

INSERT INTO `trip_job_lock` VALUES ('1', NULL, '0/5 * * * * ?', NULL);

2、后端实现方法

//(1)Mapper接口

public interface JobMapper {

    @Select("<script>SELECT is_lock FROM trip_job_lock WHERE job_name = #{jobName}</script>")
    public String getIsLock(String jobName);

    @Select("<script>SELECT job_cron FROM trip_job_lock WHERE job_name = #{jobName}</script>")
    public String getCron(String jobName);
}




//(2)定时任务实现SchedulingConfigurer接口

@Component
@SuppressWarnings("all")
@Slf4j
@EnableScheduling
@Configuration
public class AirTicketSettlementScheduler implements SchedulingConfigurer {

    @Resource
    private AirTicketSettlementTaskService airTicketSettlementTaskService;
    
    @Resource
    CtripUtil ctripUtil;

    @Autowired
    SnowFlake snowFlake;

    @Autowired
    ScheduledByRedisIP scheduledByRedisIP;

    @Autowired
    LogRecordService logRecordService;

    //飞机结算的url
    @Value("${FlightSettlementURL}")
    private String FlightSettlementURL;

    @Resource
    JobMapper jobMapper;
    
	@Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.addTriggerTask(
            //1.添加任务内容(Runnable)
            () -> //System.out.println("执行定时任务2: " + LocalDateTime.now().toLocalTime()),
                isScheduler(),
            //2.设置执行周期(Trigger)
            triggerContext -> {
                //2.1 从数据库获取执行周期
                String cron = jobMapper.getCron("AirTicketSettlementScheduler");
                //2.2 合法性校验.
                if (StringUtils.isEmpty(cron)) {
                    // Omitted Code ..
                }

                //2.3 返回执行周期(Date)
                return new CronTrigger(cron).nextExecutionTime(triggerContext);
            }
        );
    }

    //判断定时任务是否已关闭
    public void isScheduler(){
        String isLock = jobMapper.getIsLock("AirTicketSettlementScheduler");
        if("1".equals(isLock)) {
            updateAirSettlementTask();
        }else{
            log.info("机票结算数据入库定时任务已关闭！");
        }
    }

	private void updateAirSettlementTask() {
			//定时任务需要执行的任务
			//..............
	}
}