Spring使用之：Quartz定时任务为什么会被阻塞

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。

转载自：
http://wangrui.iteye.com/blog/159061