SpringBoot 异步任务

异步任务

1. 开启异步任务（在SpringBootApplication类上添加注解）

@EnableAsync

2. 异步任务

import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Component;

import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

/**
 *  @title 异步任务-业务类
 *  @Desc
 *  @author <a href="mailto:avaos.wei@gmail.com">avaos.wei</a>
 *  @Date 2020-03-25 16:05
 *
 */
@Slf4j
@Component
@Async
public class AsyncTask {

    public void task1() {
        calc("task1", 1000);
    }

    public void task2() {
        calc("task2", 2000);
    }

    public void task3() {
        calc("task3", 3000);
    }

    public Future<String> task4() throws InterruptedException {
        calc("task4", 3000);
//        Thread.sleep(1000);
        return new AsyncResult<String>("task 4 finish.");
    }

    public Future<String> task5() throws InterruptedException {
        calc("task5", 2000);
//        Thread.sleep(2000);
        return new AsyncResult<String>("task 5 finish.");
    }

    public Future<String> task6() throws InterruptedException {
        calc("task6", 1000);
//        Thread.sleep(3000);
        return new AsyncResult<String>("task 6 finish.");
    }

    private void calc(String msg, long time) {
        long start = System.nanoTime();

        try {
            Thread.sleep(time);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }

        long end = System.currentTimeMillis();

        log.info("{}: {}", msg, TimeUnit.NANOSECONDS.toMillis(end-start));
    }
}

3. 使用

import cn.avaos.task.AsyncTask;
import cn.avaos.web.domain.JsonData;
import lombok.extern.slf4j.Slf4j;
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.concurrent.Future;
import java.util.concurrent.TimeUnit;

/**
 *  @title 概述
 *  @Desc  描述
 *  @author <a href="mailto:avaos.wei@gmail.com">avaos.wei</a>
 *  @Date 2020-03-25 16:14
 *  
 */
@Slf4j
@RestController
@RequestMapping("/api/user")
public class UserController {


    @Autowired
    private AsyncTask asyncTask;

    @GetMapping(path = "/async_task")
    public JsonData execTask() {

        long start = System.nanoTime();

        asyncTask.task1();

        asyncTask.task2();

        asyncTask.task3();

        long end = System.nanoTime();

        log.info("总耗时：{}", TimeUnit.NANOSECONDS.toMillis(end-start));

        return JsonData.ok();
    }

    @GetMapping(path = "/async_task_result")
    public JsonData execTask2() throws InterruptedException {

        long start = System.nanoTime();

        Future<String> task4 = asyncTask.task4();
        Future<String> task5 = asyncTask.task5();
        Future<String> task6 = asyncTask.task6();

        while(true) {
            if(task4.isDone() && task5.isDone() && task6.isDone())
                break;
        }

        long end = System.nanoTime();

        log.info("总耗时：{}", TimeUnit.NANOSECONDS.toMillis(end-start));

        return JsonData.ok();
    }
}

4. 注意

• 要把异步任务封装在类里面，不能直接写在Controller类中
• 增加Future 返回结果AsyncResult(“任务执行完成”)
• 如果需要拿到结果，需要判断全部的task.isDone()

5. 测试
   浏览器访问：

• GET /api/user/async_task_result
• GET /api/user/async_task