SpringBoot使用异步任务

1. 开启异步任务

package com.pibigstar;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;

@SpringBootApplication
@EnableAsync //开启异步任务
public class SpringbootDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootDemoApplication.class, args);
    }
}

2. 编写异步任务

package com.pibigstar.task;

import java.util.concurrent.Future;

import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Component;

@Component
public class AsyncTask {

    @Async //异步方法注解
    public Future task1() throws InterruptedException {
        long start = System.currentTimeMillis();
        Thread.sleep(1000);
        long end = System.currentTimeMillis();
        System.out.println("=====任务1 耗时："+(end-start)+"======");
        //返回true，告诉此任务已完成
        return new AsyncResult(true);
    }

    @Async //异步方法注解
    public Future task2() throws InterruptedException {
        long start = System.currentTimeMillis();
        Thread.sleep(800);
        long end = System.currentTimeMillis();
        System.out.println("=====任务2 耗时："+(end-start)+"======");
        //返回true，告诉此任务已完成
        return new AsyncResult(true);
    }

    @Async //异步方法注解
    public Future task3() throws InterruptedException {
        long start = System.currentTimeMillis();
        Thread.sleep(600);
        long end = System.currentTimeMillis();
        System.out.println("=====任务3 耗时："+(end-start)+"======");
        //返回true，告诉此任务已完成
        return new AsyncResult(true);
    }
}

3. 启动异步任务

package com.pibigstar.web;

import java.util.concurrent.Future;

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 com.pibigstar.task.AsyncTask;

@RestController
@RequestMapping("/task")
public class AsyncTaskController {

    @Autowired
    private AsyncTask asyncTask;

    @GetMapping("test")
    public String test() throws InterruptedException {
        long start = System.currentTimeMillis();
        Future a = asyncTask.task1();
        Future b = asyncTask.task2();
        Future c = asyncTask.task3();

        //循环到三个任务全部完成
        while (!a.isDone()||!b.isDone()||!c.isDone()) {
            if (a.isDone()&&b.isDone()&&c.isDone()) {
                break;
            }
        }
        long end = System.currentTimeMillis();
        String result = "任务完成，一共用时为："+(end-start)+"毫秒";
        System.out.println(result);
        return result;  
    }
}

4. 运行结果

任务1 睡眠了 1000毫秒，任务2 睡眠了800毫秒，任务3 睡眠了600毫秒，如果是同步执行的话三个任务完成应该是2400毫秒，而这里只使用了1005毫秒，说明我们的任务执行确实是异步执行

5. 异步执行使用场景