8

有一个用于异步方法的 Spring 配置类：

@Configuration
@EnableAsync(proxyTargetClass = true)
@EnableScheduling
public class AsyncConfiguration {

@Autowired
private ApplicationContext applicationContext;

@Bean
public ActivityMessageListener activityMessageListener() {
    return new ActivityMessageListener();
}
@Bean
public TaskExecutor defaultExecutor()
{
    ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
    threadPoolTaskExecutor.setCorePoolSize(10);
    threadPoolTaskExecutor.setMaxPoolSize(10);
    threadPoolTaskExecutor.setQueueCapacity(Integer.MAX_VALUE);

    return threadPoolTaskExecutor;
}

我所有的@Async方法都按预期工作，但如果我为了捕获实现方法的异常而实现AsyncConfigurer，我的 bean 没有被代理，因此方法不会在池执行器中运行。AsyncConfigurationgetAsyncUncaughtExceptionHandler()@Async

这是非工作配置：

@Configuration
@EnableAsync(proxyTargetClass = true)
@EnableScheduling
public class AsyncConfiguration implements AsyncConfigurer {

@Autowired
private ApplicationContext applicationContext;

@Bean
public ActivityMessageListener activityMessageListener() {
    return new ActivityMessageListener();
}

@Override
public Executor getAsyncExecutor() {
    ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
    threadPoolTaskExecutor.setCorePoolSize(10);
    threadPoolTaskExecutor.setMaxPoolSize(10);
    threadPoolTaskExecutor.setQueueCapacity(Integer.MAX_VALUE);

    return threadPoolTaskExecutor;
}

@Override
public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler()        {
    return new SimpleAsyncUncaughtExceptionHandler();
}

会发生什么？

我们是@Async这样使用的：

public class ActivityMessageListener extends BaseMessageListener {

public static final String PARAM_USER_ID                = "userId";
public static final String PARAM_COMPANY_ID             = "companyId";
public static final String PARAM_CREATE_DATE            = "createDate";
public static final String PARAM_CLASS_NAME             = "className";
public static final String PARAM_CLASS_PK               = "classPK";
public static final String PARAM_TYPE                   = "type";
public static final String PARAM_EXTRA_DATA             = "extraData";
public static final String PARAM_RECEIVED_USER_ID       = "receiverUserId";

@Override @Async(value = "defaultExecutor")
public Future<String> doReceive(Message message) throws Exception {

    String name = Thread.currentThread().getName();
    Map<String, Object> parameters  = message.getValues();
    Long userId                     = (Long)parameters.get(ActivityMessageListener.PARAM_USER_ID);
    Long companyId                  = (Long)parameters.get(ActivityMessageListener.PARAM_COMPANY_ID);
    Date createDate                 = (Date)parameters.get(ActivityMessageListener.PARAM_CREATE_DATE);
    String className                = (String)parameters.get(ActivityMessageListener.PARAM_CLASS_NAME);
    Long classPK                    = (Long)parameters.get(ActivityMessageListener.PARAM_CLASS_PK);
    Integer type                    = (Integer)parameters.get(ActivityMessageListener.PARAM_TYPE);
    String extraData                = (String)parameters.get(ActivityMessageListener.PARAM_EXTRA_DATA);
    Long receiverUserId             = (Long)parameters.get(ActivityMessageListener.PARAM_RECEIVED_USER_ID);
    ActivityLocalServiceUtil.addActivity(userId, companyId, createDate, className, classPK, type, extraData, receiverUserId);

    return new AsyncResult<String>(name);
}
}
4

1 回答 1

9

编辑：我已经提交了一个错误报告 (SPR-14630)。

我即将向 Spring 的问题跟踪器提交错误报告，但是当我准备一个小应用程序来重现错误时，我发现并修复了问题。

首先，在使用时ThreadPoolTaskExecutor，你应该在返回之前调用它的initialize()方法：

@Override
public Executor getAsyncExecutor() {
    ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
    executor.setMaxPoolSize(1);
    executor.setCorePoolSize(1);
    executor.setThreadNamePrefix("CUSTOM-");

    // Initialize the executor
    executor.initialize();

    return executor;
}

同样出于某种原因，如果我@PostConstruct在同一配置类中定义的方法中使用 bean，它不会异步运行。原因是该@PostConstruct方法在执行之前getAsyncExecutor()并被getAsyncUncaughtExceptionHandler()执行：

AsyncBean.java：

@Component
public class AsyncBean implements IAsyncBean {

    @Override
    @Async
    public void whoAmI() {
        final String message =
                String.format("My name is %s and I am running in %s", getClass().getSimpleName(), Thread.currentThread());

        System.out.println(message);
    }
}

AsyncDemoApp.java：

@SpringBootApplication
@EnableAsync
public class AsyncDemoApp implements AsyncConfigurer {

    @Autowired
    private IAsyncBean asyncBean;

    public static void main(String[] args) {
        SpringApplication.run(AsyncDemoApp.class, args);
    }

    @Override
    public Executor getAsyncExecutor() {
        System.out.println("AsyncDemoApp.getAsyncExecutor");

        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setThreadNamePrefix("CUSTOM-");
        executor.initialize();

        return executor;
    }

    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        System.out.println("AsyncDemoApp.getAsyncUncaughtExceptionHandler");
        return (throwable, method, objects)
                -> throwable.printStackTrace();
    }

    @PostConstruct
    public void start() {
        System.out.println("AsyncDemoApp.start");
        asyncBean.whoAmI();
    }
}

输出：

AsyncDemoApp.start
My name is AsyncBean and I am running in Thread[main,5,main]
AsyncDemoApp.getAsyncExecutor
AsyncDemoApp.getAsyncUncaughtExceptionHandler

但是，如果您在应用程序上下文准备好使用后使用您的 bean，它应该会按预期工作：

@SpringBootApplication
@EnableAsync
public class AsyncDemoApp implements AsyncConfigurer {

    public static void main(String[] args) {
        final ConfigurableApplicationContext context = SpringApplication.run(AsyncDemoApp.class, args);

        final IAsyncBean asyncBean = context.getBean(IAsyncBean.class);

        asyncBean.whoAmI();
    }

    @Override
    public Executor getAsyncExecutor() {
        System.out.println("AsyncDemoApp.getAsyncExecutor");

        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setThreadNamePrefix("CUSTOM-");
        executor.initialize();

        return executor;
    }

    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        System.out.println("AsyncDemoApp.getAsyncUncaughtExceptionHandler");
        return (throwable, method, objects)
                -> throwable.printStackTrace();
    }
}

另一个奇怪的行为是，如果您在同一配置类中自动装配异步 bean，则自动装配发生在配置自定义异步执行器之前，因此 bean 不会异步运行，而是在主线程中运行。这可以通过添加 a并使用 a来运行应用程序@PostConstruct来验证（我个人认为这是一个错误。至少可以说这种行为非常令人惊讶）：AsyncBeanCommandLineRunner

AsyncBean与@PostConstruct：

@Component
public class AsyncBean implements IAsyncBean {

    @Override
    @Async
    public void whoAmI() {
        final String message =
                String.format("My name is %s and I am running in %s", getClass().getSimpleName(), Thread.currentThread());

        System.out.println(message);
    }

    @PostConstruct
    public void postConstruct() {
        System.out.println("AsyncBean is constructed");
    }
}

AsyncDemoApp实施CommandLineRunner：

@SpringBootApplication
@EnableAsync
public class AsyncDemoApp implements AsyncConfigurer, CommandLineRunner {

    @Autowired
    private IAsyncBean asyncBean;

    public static void main(String[] args) {
        SpringApplication.run(AsyncDemoApp.class, args);
    }

    @Override
    public Executor getAsyncExecutor() {
        System.out.println("AsyncDemoApp.getAsyncExecutor");

        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setThreadNamePrefix("CUSTOM-");
        executor.initialize();

        return executor;
    }

    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        System.out.println("AsyncDemoApp.getAsyncUncaughtExceptionHandler");
        return (throwable, method, objects)
                -> throwable.printStackTrace();
    }

    @Override
    public void run(String... args) throws Exception {
        System.out.println("AsyncDemoApp.run");
        asyncBean.whoAmI();
    }
}

输出：

AsyncBean is constructed
AsyncDemoApp.getAsyncExecutor
AsyncDemoApp.getAsyncUncaughtExceptionHandler
AsyncDemoApp.run
My name is AsyncBean and I am running in Thread[main,5,main]

还有一件事！:) 如果您使用ThreadPoolTaskExecutor，根据您的要求，您可能希望将其 daemon 属性设置为 true，否则您的应用程序将永远运行（这对于 Web/Worker 应用程序来说不是一个大问题）。这是 JavaDocsetDaemon(boolean)所说的：

设置这个工厂是否应该创建守护线程，只要应用程序本身正在运行就执行。默认为“false”：具体工厂通常支持显式取消。因此，如果应用程序关闭，Runnables 将默认完成其执行。指定“true”以急切关闭在应用程序本身关闭时仍积极执行 Runnable 的线程。

于 2016-08-26T05:21:10.110 回答