spring quartz使用多线程并发“陷阱”（转）

定义一个job：ranJob，设置每秒执行一次，设置不容许覆盖并发执行

    <bean id="rankJob" class="com.chinacache.www.logstat.job.RankJob" />  
    <bean id="rankJobDetail"  
        class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">  
        <property name="targetObject" ref="rankJob" />  
        <property name="targetMethod" value="execute" />  
        <property name="concurrent" value="false" />  
    </bean>  
    <bean id="rankJobTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerBean">  
        <property name="jobDetail" ref="rankJobDetail" />  
        <!-- 单位 ms，半小时 1800000 ms -->  
        <property name="repeatInterval" value="1000 />  
    </bean>  

java 代码

public void execute() throws InterruptedException {  
        System.out.println("Start job");  
        ExecutorService exec = Executors.newFixedThreadPool(1);  
          
        Thread thread = new Thread(new Runnable() {  
            @Override  
            public void run() {  
                System.out.println("thread start");  
                try {  
                    Thread.sleep(3000);  
                } catch (InterruptedException e) {  
                    // TODO Auto-generated catch block  
                    e.printStackTrace();  
                }  
                System.out.println("thread end");  
            }  
        });  
        exec.execute(thread);  
        exec.shutdown();  
           while (!exec.isTerminated()) {  
               // 等待全部子线程结束，才退出主线程  
           }          
        System.out.println("end job");  
    }  

 

打印结果以下：

    Start job  
    thread start  
    thread end  
    end job  
      
    Start job  
    thread start  
    thread end  
    end job  
      
    Start job  
    thread start  
    thread end  
    end job  

使用isTerminated()方法等多线程结束后在结束job；多线程任务派发结束后，要使用shutdown()方法顺序关闭线程（等待正在执行任务，不接受新任务）

 

定义一个job：ranJob，设置每秒执行一次，设置不容许覆盖并发执行

<bean id="rankJob" class="com.chinacache.www.logstat.job.RankJob" />
<bean id="rankJobDetail"
    class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
    <property name="targetObject" ref="rankJob" />
    <property name="targetMethod" value="execute" />
    <property name="concurrent" value="<span style="color: #ff0000;"><strong>false</strong></span>" />
</bean>
<bean id="rankJobTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerBean">
    <property name="jobDetail" ref="rankJobDetail" />
    <!-- 单位 ms，半小时 1800000 ms -->
    <property name="repeatInterval" value="<span style="color: #ff0000;"><strong>1000</strong></span>" />
</bean>

 

job代码：

System.out.println("Start job");
ExecutorService exec = Executors.newFixedThreadPool(1);

Thread thread = new Thread(new Runnable() {
    @Override
    public void run() {
        System.out.println("thread start");
        try {
            Thread.sleep(3000);
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.out.println("thread end");
    }
});
exec.execute(thread);
System.out.println("end job");

 

程序输出结果：

Start job
end job
<span style="color: #ff0000;"><strong>thread start</strong></span>
Start job
end job
thread start
Start job
end job
thread start
Start job
end job
thread start
<strong><span style="color: #ff0000;">thread end</span></strong>

 

从结果能够看到，job的并发覆盖配置彷佛根本没有生效，缘由是：job没有关注多线程执行状况

修改job代码，添加以下代码在job访问最后，线程处理完job才结束，

 

while (!exec.isTerminated()) {
    // 等待全部子线程结束，才退出主线程
}

 

修改代码后程序结果：

Start job
thread start
thread end

 

能够看到job始终没有结束，说明ExecutorService始终没有终止，看看文档，加入shutdonw()方法，job全部代码以下：

public void execute() throws InterruptedException {
    System.out.println("Start job");
    ExecutorService exec = Executors.newFixedThreadPool(1);

    Thread thread = new Thread(new Runnable() {
        @Override
        public void run() {
            System.out.println("thread start");
            try {
                Thread.sleep(3000);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println("thread end");
        }
    });
    exec.execute(thread);
    exec.shutdown();
       while (!exec.isTerminated()) {
           // 等待全部子线程结束，才退出主线程
       }
    System.out.println("end job");
}

 

打印结果以下：

 

Start job
thread start
thread end
end job

Start job
thread start
thread end
end job

Start job
thread start
thread end
end job

 

 

OK，至此spring quartz多线程并发问题解决。回顾下，咱们要使用isTerminated()方法等多线程结束后在结束job；多线程任务派发结束后，要使用shutdown()方法顺序关闭线程（等待正在执行任务，不接受新任务）