Question

我是Spring的异步任务执行新手，所以如果这听起来像个愚蠢的问题，请原谅我。

我读到从Spring 3.x开始在方法级别引入@Async注释，以便异步发生该方法的调用。我还读到我们可以在spring配置文件中配置ThreadPoolTaskExecutor。

我无法理解的是，如何从tak执行器调用@Async注释方法让我们假设 - AsyncTaskExecutor

早些时候我们曾经做过类似的事情：

@Autowired protected AsyncTaskExecutor executor;

然后

executor.submit(<Some Runnable or Callable task>)

我无法理解@Async注释方法与TaskExecutor之间的关系。

我尝试在互联网上搜索很多东西，但却无法得到任何东西。

有人可以为此提供一个例子。

Answer 1

以下是@Async使用的示例：

@Async
void doSomething() {
    // this will be executed asynchronously
}

现在从另一个类调用该方法，它将异步运行。如果您想要返回值，请使用Future

@Async
Future<String> returnSomething(int i) {
    // this will be executed asynchronously
}

@Async和TaskExecutor之间的关系是@Async在幕后使用TaskExecutor。来自文档：

默认情况下，在方法上指定@Async时，将使用的执行程序是提供给'annotation-driven'元素的执行程序，如上所述。但是，当需要指示在执行给定方法时应该使用除默认值之外的执行程序时，可以使用@Async批注的value属性。

因此，要设置默认执行程序，请将其添加到spring config

<task:annotation-driven executor="myExecutor" />

或者使用特定执行程序一次性尝试

@Async("otherExecutor")

请参阅http://docs.spring.io/spring/docs/3.2.x/spring-framework-reference/html/scheduling.html#scheduling-annotation-support-async

Answer 2

完整示例

Config Spring

@Configuration        
@EnableAsync        
@ComponentScan("com.async")
public class AppConfig {

    @Bean
    public AsyncManager asyncManger() {
        return new AsyncManager();
    }

    @Bean
    public AsyncExecutor asyncExecutor() {
        return new AsyncExecutor();
    }
}

Executor Class Created，Executor我已创建，以便spring负责线程管理。

public class AsyncExecutor extends AsyncConfigurerSupport {

    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(2);
        executor.setMaxPoolSize(2);
        executor.setQueueCapacity(500);
        executor.setThreadNamePrefix("Violation-");
        executor.initialize();
        return executor;
    }
}

创建经理。

public class AsyncManager {

    @Autowired
    private AsyncService asyncService;

    public void doAsyncTask(){
        try {
            Map<Long, ViolationDetails> violation = asyncService.getViolation();
            if(!org.springframework.util.CollectionUtils.isEmpty(violation)){
                violation.entrySet().forEach( violationEntry -> {System.out.println(violationEntry.getKey() +"" +violationEntry.getValue());});
            }
            System.out.println("do some async task");
        } catch (Exception e) {
        }

    }
}

配置您的服务类。

@Service
public class AsyncService {

    @Autowired
    private AsyncExecutor asyncExecutor;

    @Async
    public Map<Long,ViolationDetails> getViolation() {
        // TODO Auto-generated method stub
        List<Long> list = Arrays.asList(100l,200l,300l,400l,500l,600l,700l);
        Executor executor = asyncExecutor.getAsyncExecutor();
        Map<Long,ViolationDetails>  returnMap = new HashMap<>();
        for(Long estCode : list){
            ViolationDetails violationDetails = new ViolationDetails(estCode);
            returnMap.put(estCode, violationDetails);
            executor.execute((Runnable)new ViolationWorker(violationDetails));
        }
        return returnMap;       
    }
}
class ViolationWorker implements Runnable{

    private ViolationDetails violationDetails;

    public ViolationWorker(ViolationDetails violationDetails){
        this.violationDetails = violationDetails;
    }

    @Override
    public void run() {
        violationDetails.setViolation(System.currentTimeMillis());
        System.out.println(violationDetails.getEstablishmentID() + "    " + violationDetails.getViolation());
    }
}

模型。

public class ViolationDetails {
    private long establishmentID;
    private long violation;


    public ViolationDetails(long establishmentID){
        this.establishmentID = establishmentID;
    }

    public long getEstablishmentID() {
        return establishmentID;
    }
    public void setEstablishmentID(long establishmentID) {
        this.establishmentID = establishmentID;
    }
    public long getViolation() {
        return violation;
    }
    public void setViolation(long violation) {
        this.violation = violation;
    }

}

测试运行

public class AppTest {
    public static void main(String[] args) throws SQLException {
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
        ctx.register(AppConfig.class);
        ctx.refresh();

        AsyncManager task= ctx.getBean(AsyncManager.class);
        task.doAsyncTask();
    }
}

Answer 3

在配置文件中，应该提到带有线程池名称的注释驱动任务，带有@Async（池名称）的方法将作为该池的一部分执行。这将为具有@Async批注的代理类创建一个代理类，并为每个线程执行它。

Answer 4

您可以在方法和以下内容中将@Async添加到您的应用程序上下文中。

    <task:annotation-driven executor="asynExecutor"/>   
    <task:executor id="asynExecutor" pool-size="5" />

Spring 3：如何从TaskExecutor调用@Async注释方法

4 个答案: