Spring Task如何动态修改任务执行计划cron

package com.xindatai.ibs.lime.dycSchedul;
import java.util.Date;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Lazy;
import org.springframework.scheduling.Trigger;
import org.springframework.scheduling.TriggerContext;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.scheduling.support.CronTrigger;
import org.springframework.stereotype.Component;

/**
 * Spring动态周期定时任务 在不停应用的情况下更改任务执行周期
 * 
 * @author Liang
 *
 *         2017年6月1日
 */
@Lazy(false)
@Component
@EnableScheduling
public class SpringDynamicCornTask implements SchedulingConfigurer {
    private static final Logger logger = LoggerFactory.getLogger(SpringDynamicCornTask.class);
    private static String cron;
    private SpringDynamicCornTask() {
        cron = "0/5 * * * * ?";
        // 开启新线程模拟外部更改了任务执行周期
        new Thread(new Runnable() {

            @Override
            public void run() {
                try {
                    Thread.sleep(15 * 1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                cron = "0/10 * * * * ?";
                System.out.println("cron change to : " + cron);
            }
        }).start();
    }

    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        taskRegistrar.addTriggerTask(new Runnable() {

            @Override
            public void run() {
                // 任务逻辑
                logger.info("dynamicCronTask is running...");
            }
        }, new Trigger() {

            @Override
            public Date nextExecutionTime(TriggerContext triggerContext) {
                // 任务触发，可修改任务的执行周期
                CronTrigger trigger = new CronTrigger(cron);
                Date nextExecutionTime = trigger.nextExecutionTime(triggerContext);
                return nextExecutionTime;
            }
        });
    } 
}