Springboot Async方法在同一线程中运行 [英] Springboot Async method run in same thread

问题描述

我正在春季靴2中测试 @Async ，并且我遵循了一些在线教程

I am testing out @Async in a spring boot 2, and i followed some online tutorial

我的配置类:

@Configuration
@EnableAsync
public class AsyncConfig {

    @Bean
    public Executor asyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(5);
        executor.setMaxPoolSize(5);
        executor.setQueueCapacity(500);
        executor.setThreadNamePrefix("Async Process-");
        executor.initialize();
        return executor;
    }
}

我的控制器"的片段:

@GetMapping("/test/async")
public void testAsync() {
    System.err.println("Thread in controller: " + Thread.currentThread().getName());
    TestAsyncClazz clazz = new TestAsyncClazz();
    clazz.testAsyncMethod();
}

我的 TestAsyncClass :

public class TestAsyncClazz {

    @Async
    public void testAsyncMethod(){
        System.err.println("Running async: "+ Thread.currentThread().getName());
    }
}

当我检查打印行时，它表明我的两个方法都在同一线程上运行，并且未使用threadNamePrefix Async Process-:

When i check the print line, it shows that both of my method running on the same thread, and it didn't use the threadNamePrefix Async Process-:

Thread in controller: http-nio-8080-exec-2
Running async: http-nio-8080-exec-2

我做错了什么?我误会了吗?

What i did wrong? Did i misunderstand something?

推荐答案

之所以会发生这种情况，是因为您正在使用 new 实例化自己的类上调用异步方法:

This happens because you are calling the async method on a class that you instantiate yourself using new:

TestAsyncClazz clazz = new TestAsyncClazz();
clazz.testAsyncMethod();

如果采用这种方式，Spring将没有机会用必要的代理类来装饰实例，该代理类提供了异步运行方法的实际功能.

If you do it this way, Spring does not have a chance to decorate the instance with the necessary proxy class that provides the actual functionality to run the method asynchronously.

这只会按您期望的方式在Spring bean上起作用-换句话说，不要自己实例化 TestAsyncClazz ；定义该类的Spring bean实例，将该bean自动装配到控制器中，然后在bean上调用该方法.

This will only work the way you expect on Spring beans - in other words, do not instantiate TestAsyncClazz yourself; define a Spring bean instance of the class, autowire that bean into your controller and then call the method on the bean.

示例:

@Configuration
@EnableAsync
public class AsyncConfig {

    @Bean
    public Executor asyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(5);
        executor.setMaxPoolSize(5);
        executor.setQueueCapacity(500);
        executor.setThreadNamePrefix("Async Process-");
        executor.initialize();
        return executor;
    }

    // Define a Spring bean of type TestAsyncClazz
    @Bean
    public TestAsyncClazz testAsyncClazz() {
        return new TestAsyncClazz();
    }
}

@Controller
public class MyController {

    // Inject the bean here
    @Autowired 
    private TestAsyncClazz testAsyncClass;

    @GetMapping("/test/async")
    public void testAsync() {
        System.err.println("Thread in controller: " +
                Thread.currentThread().getName());

        // Use the bean instead of instantiating the class yourself
        testAsyncClass.testAsyncMethod();
    }
}

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