Spring线程池ThreadPoolTaskExecutor配置详情
作者:低调的小黑
本文介绍了Spring线程池ThreadPoolTaskExecutor配置,分享给大家,具体如下:
1. ThreadPoolTaskExecutor配置
<!-- spring thread pool executor --> <bean id="taskExecutor" class="org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor"> <!-- 线程池维护线程的最少数量 --> <property name="corePoolSize" value="5" /> <!-- 允许的空闲时间 --> <property name="keepAliveSeconds" value="200" /> <!-- 线程池维护线程的最大数量 --> <property name="maxPoolSize" value="10" /> <!-- 缓存队列 --> <property name="queueCapacity" value="20" /> <!-- 对拒绝task的处理策略 --> <property name="rejectedExecutionHandler"> <bean class="java.util.concurrent.ThreadPoolExecutor$CallerRunsPolicy" /> </property> </bean>
属性字段说明
corePoolSize:线程池维护线程的最少数量
keepAliveSeconds:允许的空闲时间
maxPoolSize:线程池维护线程的最大数量
queueCapacity:缓存队列
rejectedExecutionHandler:对拒绝task的处理策略
2. execute(Runable)方法执行过程
如果此时线程池中的数量小于corePoolSize,即使线程池中的线程都处于空闲状态,也要创建新的线程来处理被添加的任务。
如果此时线程池中的数量等于 corePoolSize,但是缓冲队列 workQueue未满,那么任务被放入缓冲队列。
如果此时线程池中的数量大于corePoolSize,缓冲队列workQueue满,并且线程池中的数量小于maxPoolSize,建新的线程来处理被添加的任务。
如果此时线程池中的数量大于corePoolSize,缓冲队列workQueue满,并且线程池中的数量等于maxPoolSize,那么通过handler所指定的策略来处理此任务。也就是:处理任务的优先级为:核心线程corePoolSize、任务队列workQueue、最大线程 maximumPoolSize,如果三者都满了,使用handler处理被拒绝的任务。
当线程池中的线程数量大于corePoolSize时,如果某线程空闲时间超过keepAliveTime,线程将被终止。这样,线程池可以动态的调整池中的线程数。
3. 示例代码
Junit Test
@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration(classes = { MultiThreadConfig.class }) public class MultiThreadTest { @Autowired private ThreadPoolTaskExecutor taskExecutor; @Autowired private MultiThreadProcessService multiThreadProcessService; @Test public void test() { int n = 20; for (int i = 0; i < n; i++) { taskExecutor.execute(new MultiThreadDemo(multiThreadProcessService)); System.out.println("int i is " + i + ", now threadpool active threads totalnum is " + taskExecutor.getActiveCount()); } try { System.in.read(); } catch (IOException e) { throw new RuntimeException(e); } } }
MultiThreadDemo
/** * 多线程并发处理demo * @author daniel.zhao * */ public class MultiThreadDemo implements Runnable { private MultiThreadProcessService multiThreadProcessService; public MultiThreadDemo() { } public MultiThreadDemo(MultiThreadProcessService multiThreadProcessService) { this.multiThreadProcessService = multiThreadProcessService; } @Override public void run() { multiThreadProcessService.processSomething(); } }
MultiThreadProcessService
@Service public class MultiThreadProcessService { public static final Logger logger = Logger.getLogger(MultiThreadProcessService.class); /** * 默认处理流程耗时1000ms */ public void processSomething() { logger.debug("MultiThreadProcessService-processSomething" + Thread.currentThread() + "......start"); try { Thread.sleep(1000); } catch (InterruptedException e) { throw new RuntimeException(e); } logger.debug("MultiThreadProcessService-processSomething" + Thread.currentThread() + "......end"); } }
MultiThreadConfig
@Configuration @ComponentScan(basePackages = { "com.xxx.multithread" }) @ImportResource(value = { "classpath:config/application-task.xml" }) @EnableScheduling public class MultiThreadConfig { }
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。