quartz+spring 实现多任务动态定时器问题

这里有个 spring quartz 动态任务执行的例子。
Maven 依赖
         <dependency>
            <groupId>org.quartz-scheduler</groupId>
            <artifactId>quartz</artifactId>
            <version>1.8.5</version>
         </dependency>
            <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context-support</artifactId>
            <version>${spring.version}</version>
        </dependency>Application Context 配置
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
    xsi:schemaLocation="
            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
            http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd
            http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
            http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-3.0.xsd
            http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
            http://www.springmodules.org/schema/ehcache http://www.springmodules.org/schema/cache/springmodules-ehcache.xsd">
    <!-- The Task Bean-->
    <bean id="myTask" class="com.xxx.example.dynamicjob.MyTask" />    <!-- The quartz scheduler configuration -->
    <bean id="scheduler" class="org.springframework.scheduling.quartz.SchedulerFactoryBean"/></beans>java 任务类
package com.xxx.example.dynamicjob;    public class MyTask
    {
        public void performAction() {
            System.out.println("Hey, you reached me...:)");
        }          
    }创建一个动态任务的 java 类：
package com.xxx.example.dynamicjob;
import org.quartz.JobDetail;
import org.quartz.Scheduler;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.core.io.ClassPathResource;
import org.springframework.scheduling.quartz.CronTriggerBean;
import org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean;public class DynamicJobExample {    /**
    * @param args
    */
    public static void main(String[] args) {                ClassPathResource res = new ClassPathResource("dynamic-jobs.xml");
                XmlBeanFactory factory = new XmlBeanFactory(res);                //get the quartzFactory bean
                Scheduler scheduler = (Scheduler) factory.getBean("scheduler");                //get the task bean
                MyTask myTask = (MyTask) factory.getBean("myTask");                try {
                // create JOB
                MethodInvokingJobDetailFactoryBean jobDetail = new MethodInvokingJobDetailFactoryBean();
                jobDetail.setTargetObject(myTask);
                jobDetail.setTargetMethod("performAction");
                jobDetail.setName("MyJobDetail");
                jobDetail.setConcurrent(false);
                jobDetail.afterPropertiesSet();                /* SimpleTriggerBean trigger = new SimpleTriggerBean();
                trigger.setBeanName("MyTrigger");
                trigger.setJobDetail((JobDetail) jobDetail.getObject());
                trigger.setRepeatInterval(5000);
                trigger.afterPropertiesSet();
                */                // create CRON Trigger
                CronTriggerBean cronTrigger = new CronTriggerBean();
                cronTrigger.setBeanName("CRON0001");                // Execute after each 5 second
                String expression = "5 * * * * ?";
                cronTrigger.setCronExpression(expression);
                cronTrigger.afterPropertiesSet();                //scheduler.scheduleJob(jobDetail, cronTrigger);                scheduler.scheduleJob((JobDetail) jobDetail.getObject(), cronTrigger);                // Start Scheduler        
                scheduler.start();                } catch (Exception e) {                      
                    e.printStackTrace();
                } 
    }
}