spring quartz使用多線程併發「陷阱」（轉）

定義一個job：ranJob，設置每秒執行一次，設置不容許覆蓋併發執行

    <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" />  
        <!-- 單位 ms，半小時 1800000 ms -->  
        <property name="repeatInterval" value="1000 />  
    </bean>  

java 代碼

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()) {  
               // 等待全部子線程結束，才退出主線程  
           }          
        System.out.println("end job");  
    }  

 

打印結果以下：

    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()方法等多線程結束後在結束job；多線程任務派發結束後，要使用shutdown()方法順序關閉線程（等待正在執行任務，不接受新任務）

 

定義一個job：ranJob，設置每秒執行一次，設置不容許覆蓋併發執行

<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" />
    <!-- 單位 ms，半小時 1800000 ms -->
    <property name="repeatInterval" value="<span style="color: #ff0000;"><strong>1000</strong></span>" />
</bean>

 

job代碼：

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");

 

程序輸出結果：

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>

 

從結果能夠看到，job的併發覆蓋配置彷佛根本沒有生效，緣由是：job沒有關注多線程執行狀況

修改job代碼，添加以下代碼在job訪問最後，線程處理完job才結束，

 

while (!exec.isTerminated()) {
    // 等待全部子線程結束，才退出主線程
}

 

修改代碼後程序結果：

Start job
thread start
thread end

 

能夠看到job始終沒有結束，說明ExecutorService始終沒有終止，看看文檔，加入shutdonw()方法，job全部代碼以下：

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()) {
           // 等待全部子線程結束，才退出主線程
       }
    System.out.println("end job");
}

 

打印結果以下：

 

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多線程併發問題解決。回顧下，咱們要使用isTerminated()方法等多線程結束後在結束job；多線程任務派發結束後，要使用shutdown()方法順序關閉線程（等待正在執行任務，不接受新任務）