Springboot的異步線程池圖鑑

1：定義線程池

@EnableAsync
    @Configuration
    class TaskPoolConfig {
 
        @Bean("taskExecutor")
        public Executor taskExecutor() {
            ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
            executor.setCorePoolSize(10);
            executor.setMaxPoolSize(20);
            executor.setQueueCapacity(200);
            executor.setKeepAliveSeconds(60);
            executor.setThreadNamePrefix("taskExecutor-");
            executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
executor.setWaitForTasksToCompleteOnShutdown(true);
         executor.setAwaitTerminationSeconds(60);
 return executor;
    }
}

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2：如何使用該線程池呢？

@Slf4j
@Component
public class Task {
 
    public static Random random = new Random();
@Autowired
    private StringRedisTemplate stringRedisTemplate;
@Async("taskExecutor")
    public void doTaskOne() throws Exception {
        log.info("開始作任務一");
        long start = System.currentTimeMillis();
        Thread.sleep(random.nextInt(10000));
        long end = System.currentTimeMillis();        log.info(stringRedisTemplate.randomKey());
        log.info("完成任務一，耗時：" + (end - start) + "毫秒");
    }
 
    @Async("taskExecutor")
    public void doTaskTwo() throws Exception {
        log.info("開始作任務二");
        long start = System.currentTimeMillis();
        Thread.sleep(random.nextInt(10000));
        long end = System.currentTimeMillis();
        log.info("完成任務二，耗時：" + (end - start) + "毫秒");
    }
 
    @Async("taskExecutor")
    public void doTaskThree() throws Exception {
        log.info("開始作任務三");
        long start = System.currentTimeMillis();
        Thread.sleep(random.nextInt(10000));
        long end = System.currentTimeMillis();
        log.info("完成任務三，耗時：" + (end - start) + "毫秒");
    }
 
}

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3 執行異步任務

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest
public class ApplicationTests {
 
    @Autowired
    private Task task;
 
    @Test
    public void test() throws Exception {
 
        task.doTaskOne();
        task.doTaskTwo();
        task.doTaskThree();
 
        Thread.currentThread().join();
    }
 
}

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4 打印結果

2018-03-27 22:01:15.620  INFO 73703 --- [ taskExecutor-1] com.didispace.async.Task  : 開始作任務一

2018-03-27 22:01:15.620  INFO 73703 --- [ taskExecutor-2] com.didispace.async.Task  : 開始作任務二
2018-03-27 22:01:15.620  INFO 73703 --- [ taskExecutor-3] com.didispace.async.Task  : 開始作任務三
2018-03-27 22:01:18.165  INFO 73703 --- [ taskExecutor-2] com.didispace.async.Task  : 完成任務二，耗時：2545毫秒
2018-03-27 22:01:22.149  INFO 73703 --- [ taskExecutor-3] com.didispace.async.Task  : 完成任務三，耗時：6529毫秒
2018-03-27 22:01:23.912  INFO 73703 --- [ taskExecutor-1] com.didispace.async.Task  : 完成任務一，耗時：8292毫秒

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5 注意事項

注： @Async所修飾的函數不要定義爲static類型，這樣異步調用不會生效

從異常信息JedisConnectionException: Could not get a resource from the pool來看，咱們很容易的能夠想到，在應用關閉的時候異步任務還在執行，因爲Redis鏈接池先銷燬了，致使異步任務中要訪問Redis的操做就報了上面的錯。因此，咱們得出結論，上面的實現方式在應用關閉的時候是不優雅的，那麼咱們要怎麼作呢？以下設置：

executor.setWaitForTasksToCompleteOnShutdown( true );

executor.setAwaitTerminationSeconds( 60 );