问题：
周日，公司CTO给我打电话说，监控系统的数据从下午1点就不更新了。我登录服务器排除了数据同步问题，查看日志也没有例外抛出，查询了前一天的日志发现几个数据库表空间溢出例外。最后定位，Spring定时任务挂掉了。重启应用恢复正常。周一早上，同样的问题又发生了，6点开始定时任务又停了。Spring定时任务为什么会被阻塞呢？
原因：
周一中午，我在进行接口状态监控测试时发现，接口状态查询任务尽然会执行半小时。问题找到了，由于我在接口状态查询任务中没有设置读超时、在接口网络繁忙时，接口状态查询任务会占用很长的时间，Spring定时任务默认都是并发执行的，不会等待上一次任务执行完毕，只要间隔时间到就会执行。接口状态查询任务每5分钟执行一次，假如每次都执行1小时的话，其他任务就会被阻塞。因为Quartz的线程都被接口状态查询任务占用了。其他任务只有等待。
解决方法：
1.将JobDetail的concurrent属性配置为false。不允许任务并发执行。
2.任务执行时间较长时，查找根本问题。
实验：
JobOne.java
Java代码
package test.job;
import java.util.Date;
public class JobOne {
public void execute(){
System.out.println("execute JobOne("+new Date()+")");
try {
Thread.sleep(1000000);
}catch(InterruptedException ire) {
}
}
}
package test.job;
import java.util.Date;
public class JobOne {
public void execute(){
System.out.println("execute JobOne("+new Date()+")");
try {
Thread.sleep(1000000);
}catch(InterruptedException ire) {
}
}
}
JobTwo.java
Java代码
package test.job;
import java.util.Date;
public class JobTwo {
public void execute(){
System.out.println("execute JobTwo("+new Date()+")");
}
}
package test.job;
import java.util.Date;
public class JobTwo {
public void execute(){
System.out.println("execute JobTwo("+new Date()+")");
}
}
配置文件
Xml代码
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-
beans-2.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
<!--===== jobOne =====-->
<!-- job -->
<bean id="jobOne" class="test.job.JobOne" >
</bean>
<!-- job detail -->
<bean id="jobOneDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
<property name="targetObject" ref="jobOne"/>
<property name="targetMethod" value="execute"/>
<property name="concurrent" value="true" />
</bean>
<!-- Trigger -->
<bean id="jobOneSimpleTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerBean">
<property name="jobDetail" ref="jobOneDetail" />
<property name="startDelay"><value>0</value></property>
<property name="repeatInterval"><value>1000</value></property>
</bean>
<!--===== jobTwo =====-->
<!-- job -->
<bean id="jobTwo" class="test.job.JobTwo" >
</bean>
<!-- job detail -->
<bean id="jobTwoDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
<property name="targetObject" ref="jobTwo"/>
<property name="targetMethod" value="execute"/>
<property name="concurrent" value="true" />
</bean>
<!-- Trigger -->
<bean id="jobTwoSimpleTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerBean">
<property name="jobDetail" ref="jobTwoDetail" />
<property name="startDelay"><value>0</value></property>
<property name="repeatInterval"><value>1000</value></property>
</bean>
<!--===== Schedule =====-->
<!-- schedule -->
<bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
<property name="triggers">
<list>
<ref local="jobOneSimpleTrigger"/>
<ref local="jobTwoSimpleTrigger"/>
</list>
</property>
</bean>
</beans>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">
<!--===== jobOne =====-->
<!-- job -->
<bean id="jobOne" class="test.job.JobOne" >
</bean>
<!-- job detail -->
<bean id="jobOneDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
<property name="targetObject" ref="jobOne"/>
<property name="targetMethod" value="execute"/>
<property name="concurrent" value="true" />
</bean>
<!-- Trigger -->
<bean id="jobOneSimpleTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerBean">
<property name="jobDetail" ref="jobOneDetail" />
<property name="startDelay"><value>0</value></property>
<property name="repeatInterval"><value>1000</value></property>
</bean>
<!--===== jobTwo =====-->
<!-- job -->
<bean id="jobTwo" class="test.job.JobTwo" >
</bean>
<!-- job detail -->
<bean id="jobTwoDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
<property name="targetObject" ref="jobTwo"/>
<property name="targetMethod" value="execute"/>
<property name="concurrent" value="true" />
</bean>
<!-- Trigger -->
<bean id="jobTwoSimpleTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerBean">
<property name="jobDetail" ref="jobTwoDetail" />
<property name="startDelay"><value>0</value></property>
<property name="repeatInterval"><value>1000</value></property>
</bean>
<!--===== Schedule =====-->
<!-- schedule -->
<bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
<property name="triggers">
<list>
<ref local="jobOneSimpleTrigger"/>
<ref local="jobTwoSimpleTrigger"/>
</list>
</property>
</bean>
</beans>
MAIN类：
Java代码
package test.job;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class JobTest {
private ApplicationContext ac;
public JobTest(ApplicationContext ac) {
this.ac = ac;
}
/**
* @param args
*/
public static void main(String[] args) {
JobTest job = new JobTest(new ClassPathXmlApplicationContext("applicationContext.xml"));
}
}
package test.job;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class JobTest {
private ApplicationContext ac;
public JobTest(ApplicationContext ac) {
this.ac = ac;
}
/**
* @param args
*/
public static void main(String[] args) {
JobTest job = new JobTest(new ClassPathXmlApplicationContext("applicationContext.xml"));
}
}
测试结果：
当jobOne的concurrent为true时：
execute JobOne(Thu Jan 24 13:40:22 CST 2008)
execute JobTwo(Thu Jan 24 13:40:22 CST 2008)
execute JobOne(Thu Jan 24 13:40:22 CST 2008)
execute JobTwo(Thu Jan 24 13:40:22 CST 2008)
execute JobOne(Thu Jan 24 13:40:23 CST 2008)
execute JobTwo(Thu Jan 24 13:40:23 CST 2008)
execute JobOne(Thu Jan 24 13:40:24 CST 2008)
execute JobTwo(Thu Jan 24 13:40:24 CST 2008)
execute JobOne(Thu Jan 24 13:40:25 CST 2008)
execute JobTwo(Thu Jan 24 13:40:25 CST 2008)
execute JobOne(Thu Jan 24 13:40:26 CST 2008)
execute JobTwo(Thu Jan 24 13:40:26 CST 2008)
execute JobOne(Thu Jan 24 13:40:27 CST 2008)
execute JobTwo(Thu Jan 24 13:40:27 CST 2008)
execute JobOne(Thu Jan 24 13:40:28 CST 2008)
execute JobTwo(Thu Jan 24 13:40:28 CST 2008)
execute JobOne(Thu Jan 24 13:40:29 CST 2008)
execute JobTwo(Thu Jan 24 13:40:29 CST 2008)
execute JobOne(Thu Jan 24 13:40:31 CST 2008)
（JobOne并发执行，到这里所有任务阻塞没有信息输出，可以看出默认有10个线程，都被JobOne占用）
当jobOne的concurrent为false时：
execute JobOne(Thu Jan 24 13:43:00 CST 2008)
execute JobTwo(Thu Jan 24 13:43:00 CST 2008)
execute JobTwo(Thu Jan 24 13:43:00 CST 2008)
execute JobTwo(Thu Jan 24 13:43:01 CST 2008)
execute JobTwo(Thu Jan 24 13:43:02 CST 2008)
execute JobTwo(Thu Jan 24 13:43:03 CST 2008)
execute JobTwo(Thu Jan 24 13:43:04 CST 2008)
execute JobTwo(Thu Jan 24 13:43:05 CST 2008)
execute JobTwo(Thu Jan 24 13:43:06 CST 2008)
execute JobTwo(Thu Jan 24 13:43:07 CST 2008)
execute JobTwo(Thu Jan 24 13:43:08 CST 2008)
execute JobTwo(Thu Jan 24 13:43:09 CST 2008)
（JobOne不并发执行，JobTwo不会被阻塞）
4 楼 雁行 2008-01-25 引用
我们jobdetail用的是org.springframework.scheduling.quartz.JobDetailBean
可以设置超时时间
不过从某种意义上来说，不如并发设置为false好些。
3 楼 wangrui 2008-01-24 引用
任务的时间超不超过定时器的间隔，我觉得编程时无法决定，或者说你认为它不会，实际什么情况都会发生。我这个系统运行了半年了也没出现问题。可是还是出了这样的问题。设计时还是应该好好考虑，如果任务不需要并发就将concurrent设为false比较保险。
2 楼 jones 2008-01-24 引用
implements StatefulJob使Job成为有状态的，顺序执行
1 楼 agile_boy 2008-01-24 引用
执行任务的时间不应该超过定时器的间隔吧，否则就会发生阻塞。
