SpringBoot中使用@Async注解失效问题记录

错误示例，同一个类中使用异步方法：

package com.xqnode.learning.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import org.springframework.scheduling.annotation.Async;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

@RestController
@RequestMapping("/test")
public class TestController {

    @GetMapping("/async")
    public Map<Object, Object> test() throws InterruptedException, JsonProcessingException {
        System.out.println("接收到请求。。。");
        task();
        Map<Object, Object> map = new HashMap<>();
        System.out.println("请求结束。。。");
        map.put("msg", "操作成功");
        map.put("code", "0");
        return map;
    }

    @Async
    void task() throws InterruptedException {
        TimeUnit.SECONDS.sleep(5);
        System.out.println("线程任务执行结束。。。");
    }
}

来分析下错误的原因：
当我使用postman调用该接口的时候发现，我预想中的立即返回并没有发生。后来查询资料发现，我在同一个controller中调用，在接口方法中调用了异步方法。这是不会生效的。

正确示例：

package com.xqnode.learning.controller;

import com.xqnode.learning.service.AsyncService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.HashMap;
import java.util.Map;

@RestController
@RequestMapping("/test")
public class TestController {

    private static final Logger LOG = LoggerFactory.getLogger(TestController.class);

    @Autowired
    private AsyncService asyncService;

    @GetMapping("/async")
    public Map<Object, Object> test() throws InterruptedException {
        LOG.info("接收到请求。。。");
        asyncService.task();
        Map<Object, Object> map = new HashMap<>();
        LOG.info("请求结束。。。");
        map.put("msg", "操作成功");
        map.put("code", "0");
        return map;
    }
}

将异步调用放到service中：

package com.xqnode.learning.service;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import java.util.concurrent.TimeUnit;

@Service
public class AsyncService {

    private static final Logger LOG = LoggerFactory.getLogger(AsyncService.class);


    @Async("asyncExecutor")
    public void task() throws InterruptedException {

        TimeUnit.SECONDS.sleep(5);
        LOG.info("线程任务执行结束。。。");
    }
}

这时候再重启项目请求该接口，就会发现接口可以立即返回值。而task任务是异步执行的，5秒之后才会打印结果：