spring源码分析之定时任务概述

时间:2023-12-16 16:18:38

Spring框架提供了TaskExcutor的异步执行和TashScheduler的任务定时执行接口,同样spring也提供了线程池或者CommonJ的代理。

TaskExecutor的类型

SimpleAsyncTaskExecutor,没有复用线程,当触发时仅仅启动一个新的线程。支持并发。

SyncTaskExecutor,同步触发,主要用来不需要多线程的情况,例如测试用例

ConcurrentTaskExecutor,java.util.concurrent.Executor的适配器,作为ThreadPoolTaskExecutor的替代品,很少使用,但如果ThreadPoolTaskExecutor不能满足你的需求,可以考虑使用它。

SimpleThreadPoolTaskExecutor,Quartz的SimpleThreadPool子类实现,它监听spring生命周期的callback,主要用来在quartz和非quartz组件共享线程池时。

ThreadPoolTaskExecutor,常用的TaskExecutor实现类。

WorkManagerTaskExecutor,使用了CommJ的WorkMannager作为它的实现,它提供了在spring contxt中建立一个CommonJ WorkManger的便利主类,类似于SimpleThreadPoolTaskExecutor。

注:CommonJ是BEA和IBM开发的

TaskExecutor使用示例:

import org.springframework.core.task.TaskExecutor;

public class TaskExecutorExample {

    private class MessagePrinterTask implements Runnable {

        private String message;

        public MessagePrinterTask(String message) {
this.message = message;
} public void run() {
System.out.println(message);
} } private TaskExecutor taskExecutor; public TaskExecutorExample(TaskExecutor taskExecutor) {
this.taskExecutor = taskExecutor;
} public void printMessages() {
for(int i = 0; i < 25; i++) {
taskExecutor.execute(new MessagePrinterTask("Message" + i));
}
} }

配置文件:

<bean id="taskExecutor" class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor">
<property name="corePoolSize" value="5" />
<property name="maxPoolSize" value="10" />
<property name="queueCapacity" value="25" />
</bean> <bean id="taskExecutorExample" class="TaskExecutorExample">
<constructor-arg ref="taskExecutor" />
</bean>

使用Quartz Scheduler

1. 使用JobDetailFactoryBean

<bean name="exampleJob" class="org.springframework.scheduling.quartz.JobDetailFactoryBean">
<property name="jobClass" value="example.ExampleJob"/>
<property name="jobDataAsMap">
<map>
<entry key="timeout" value="5"/>
</map>
</property>
</bean>

测试类

package example;

public class ExampleJob extends QuartzJobBean {

    private int timeout;

    /**
* Setter called after the ExampleJob is instantiated
* with the value from the JobDetailFactoryBean (5)
*/
public void setTimeout(int timeout) {
this.timeout = timeout;
} protected void executeInternal(JobExecutionContext ctx) throws JobExecutionException {
// do the actual work
} }

2. 使用MethodInvokingJobDetailFactoryBean

配置文件

<bean id="jobDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
<property name="targetObject" ref="exampleBusinessObject"/>
<property name="targetMethod" value="doIt"/>
</bean>

对应的方法

public class ExampleBusinessObject {

    // properties and collaborators

    public void doIt() {
// do the actual work
}
}
<bean id="exampleBusinessObject" class="examples.ExampleBusinessObject"/>

有状态的job,一个任务没完成之前,相同任务的下个不会执行

<bean id="jobDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
<property name="targetObject" ref="exampleBusinessObject"/>
<property name="targetMethod" value="doIt"/>
<property name="concurrent" value="false"/>
</bean>

3. 使用triggers 和SchedulerFactoryBean包装job

两种类型的TriggerFactoryBean,分别是SimpleTriggerFactoryBean和CronTriggerFactoryBean

<bean id="simpleTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerFactoryBean">
<!-- see the example of method invoking job above -->
<property name="jobDetail" ref="jobDetail"/>
<!-- 10 seconds -->
<property name="startDelay" value="10000"/>
<!-- repeat every 50 seconds -->
<property name="repeatInterval" value="50000"/>
</bean> <bean id="cronTrigger" class="org.springframework.scheduling.quartz.CronTriggerFactoryBean">
<property name="jobDetail" ref="exampleJob"/>
<!-- run every morning at 6 AM -->
<property name="cronExpression" value="0 0 6 * * ?"/>
</bean>

建立SchedulerFactoryBean

<bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
<property name="triggers">
<list>
<ref bean="cronTrigger"/>
<ref bean="simpleTrigger"/>
</list>
</property>
</bean>

参考文献:

【1】http://docs.spring.io/spring/docs/current/spring-framework-reference/html/scheduling.html

【2】http://www.cnblogs.com/davidwang456/p/4237895.html