Spring Boot中的异步方法

Question

I have a problem with sending email with method annotated as @Async. Firstly, I am not sure if it is possible to work as I want so I need help with explanation.

Here is what am doing now:

In main method i have annotation

@EnableAsync(proxyTargetClass = true)

Next I have AsyncConfig class

import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.AsyncConfigurerSupport;
import java.util.concurrent.Executor;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

@Configuration
public class AsyncConfig extends AsyncConfigurerSupport {

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

}

Of course, its rest application so i have controller, service etc, looks normally, nothing special

My async method looks like this:

    @Async
    public void sendEmail() throws InterruptedException {

        log.info("Sleep");
        Thread.sleep(10000L);    
        //method code
        log.info("Done");
    }

I executing this method in another service method:

@Override
    public boolean sendSystemEmail() {

        try {
            this.sendEmail();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        log.info("pending sendEmail method");
        return true;
    }

Now what I want archive is to ignore executing sendEmail() function and execute return true; meanwhile function sendEmail() will be executing in another Thread. Of course it doesn't work now as I want. Unfortunately.

Note that I am new into async programming, so I have lack of knowledge in some parts of this programming method.

Thanks for any help.

Answer 1

First – let's go over the rules – @Async has two limitations:

it must be applied to public methods only self-invocation – calling the async method from within the same class – won't work

The reasons are simple – the method needs to be public so that it can be proxied. And self-invocation doesn't work because it bypasses the proxy and calls the underlying method directly.

http://www.baeldung.com/spring-async