线程池ExecutorService的4种拒绝策略
-
ThreadPoolExecutor.AbortPolicy：丢弃任务并抛出RejectedExecutionException异常 -
ThreadPoolExecutor.DiscardPolicy：也是丢弃任务，但是不抛出异常。 -
ThreadPoolExecutor.DiscardOldestPolicy：丢弃队列最前面的任务，执行后面的任务 -
ThreadPoolExecutor.CallerRunsPolicy：由调用线程处理该任务
原生线程池实现
// Spring原生线程池
ThreadFactory namedThreadFactory = new ThreadFactoryBuilder()
.setNameFormat("demo-pool-%d").build();
ExecutorService singleThreadPool = new ThreadPoolExecutor(1, 1,
0L, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>(1024), namedThreadFactory, new ThreadPoolExecutor.AbortPolicy());
singleThreadPool.execute(() -> System.out.println(Thread.currentThread().getName()));
singleThreadPool.shutdown();
SpringMVC集成
xml声明
<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="2" />
<!-- 线程池维护线程的最大数量 -->
<property name="maxPoolSize" value="1000" />
<!-- 线程池所使用的缓冲队列 -->
<property name="queueCapacity" value="200" />
<!-- 线程池维护线程所允许的空闲时间 -->
<property name="keepAliveSeconds" value="2000" />
<property name="rejectedExecutionHandler">
<bean class="java.util.concurrent.ThreadPoolExecutor$AbortPolicy" />
</property>
</bean>
SpringBoot集成
/**
* 放一些自定义的Bean声明
*
* @author Created by 思伟 on 2019/12/16
*/
@Configuration
@EnableAsync
public class MyBootConfig {
/**
* 线程池维护线程的最少数量
*/
@Value("${thread-pool.core-pool-size:2}")
private int corePoolSize;
/**
* 线程池维护线程的最大数量
*/
@Value("${thread-pool.max-pool-size:1000}")
private int maxPoolSize;
/**
* 线程池所使用的缓冲队列
*/
@Value("${thread-pool.queue-capacity:200}")
private int queueCapacity;
/**
* 线程池维护线程所允许的空闲时间
*/
@Value("${thread-pool.keep-alive-seconds:2000}")
private int keepAliveSeconds;
/**
* 配置线程池中的线程的名称前缀
*/
@Value("${thread-pool.thread-name-prefix:async-resource-schedule-}")
private String threadNamePrefix;
/**
* Spring线程池
*
* @return TaskExecutor
*/
@Bean(name = AsyncExecutionAspectSupport.DEFAULT_TASK_EXECUTOR_BEAN_NAME)
@ConditionalOnMissingBean
public TaskExecutor taskExecutor() {
ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
executor.setCorePoolSize(corePoolSize);
executor.setMaxPoolSize(maxPoolSize);
executor.setQueueCapacity(queueCapacity);
executor.setKeepAliveSeconds(keepAliveSeconds);
executor.setThreadNamePrefix(threadNamePrefix);
// rejection-policy：当pool已经达到max size的时候，如何处理新任务
// CALLER_RUNS：不在新线程中执行任务，而是有调用者所在的线程来执行
executor.setRejectedExecutionHandler(new ThreadPoolExecutor.AbortPolicy());
//执行初始化
executor.initialize();
return executor;
}
}
如何使用
/**
* Spring线程池
*/
@Resource
private TaskExecutor taskExecutor;
@Override
public void run(String... args) throws Exception {
taskExecutor.execute(() -> {
log.info("Real thread begin to execute!");
});
}
