Spring Boot 异步调用方式@Async-白红宇

Spring Boot 异步调用方式@Async

阅读量：6095 次

发布时间：2019-06-20

本文共 8136 字，大约阅读时间需要 27 分钟。

1.使用背景

在日常开发的项目中，当访问其他人的接口较慢或者做耗时任务（IO等操作）时，不想程序一直卡在耗时任务上，想程序能够并行执行，我们可以使用多线程来并行的处理任务，也可以使用spring提供的异步处理方式。

2.创建AsyncTask类，在里面添加3个@Async注解的task：

import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.scheduling.annotation.Async;import org.springframework.scheduling.annotation.AsyncResult;import org.springframework.stereotype.Component;import java.util.Random;import java.util.concurrent.Future;/** * Created by Jiacheng on 2017/8/28. */@Componentpublic class AsyncTask {    private static Random random =new Random();    protected final Logger logger = LoggerFactory.getLogger(this.getClass());    @Async    public Future
    
      doTaskOne() throws Exception {        System.out.println("开始做任务一");        long start = System.currentTimeMillis();        Thread.sleep(random.nextInt(10000));        long end = System.currentTimeMillis();        System.out.println("完成任务一，耗时：" + (end - start) + "毫秒");        return new AsyncResult<>("任务一完成");    }    @Async    public Future
     
       doTaskTwo() throws Exception {        System.out.println("开始做任务二");        long start = System.currentTimeMillis();        Thread.sleep(random.nextInt(10000));        long end = System.currentTimeMillis();        System.out.println("完成任务二，耗时：" + (end - start) + "毫秒");        return new AsyncResult<>("任务二完成");    }    @Async    public Future
      
        doTaskThree() throws Exception {        System.out.println("开始做任务三");        long start = System.currentTimeMillis();        Thread.sleep(random.nextInt(10000));        long end = System.currentTimeMillis();        System.out.println("完成任务三，耗时：" + (end - start) + "毫秒");        return new AsyncResult<>("任务三完成");    }}

3.进行测试

import ncu.jerry.orangeplus.common.base.Result;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.ResponseBody;import java.util.concurrent.Future;/** * Created by Jiacheng on 2017/8/28. * * 异步操作测试类 */@Controller@RequestMapping("/async")public class AsyncController {    @Autowired    private AsyncTask task;    @RequestMapping(value = "/task", method = RequestMethod.GET)    @ResponseBody    public Result task() throws Exception {        long start = System.currentTimeMillis();        Future
    
      task1 = task.doTaskOne();        Future
     
       task2 = task.doTaskTwo();        Future
      
        task3 = task.doTaskThree();        while (true) {            if (task1.isDone() && task2.isDone() && task3.isDone()) {                // 三个任务都调用完成，退出循环等待                break;            }            Thread.sleep(1000);        }        long end = System.currentTimeMillis();        System.out.println("任务全部完成，总耗时：" + (end - start) + "毫秒");        return new Result<>(end - start);    }}

测试结果

开始做任务二开始做任务一开始做任务三完成任务二，耗时：3355毫秒完成任务一，耗时：3879毫秒完成任务三，耗时：4246毫秒任务全部完成，总耗时：5008毫秒

task执行没有自定义的Executor，使用缺省的TaskExecutor 。

前面是最简单的使用方法。如果想使用自定义的Executor，可以按照如下几步来：

1、新建Executor配置类，加入@EnableAsync注解：

import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.scheduling.annotation.EnableAsync;import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;import java.util.concurrent.Executor;import java.util.concurrent.ThreadPoolExecutor;/** * Created by Jiacheng on 2017/8/28. * * Executor配置类 */@Configuration@EnableAsyncpublic class ExecutorConfig {    /** Set the ThreadPoolExecutor's core pool size. */    private int corePoolSize = 10;    /** Set the ThreadPoolExecutor's maximum pool size. */    private int maxPoolSize = 200;    /** Set the capacity for the ThreadPoolExecutor's BlockingQueue. */    private int queueCapacity = 10;    @Bean    public Executor mySimpleAsync() {        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();        executor.setCorePoolSize(corePoolSize);        executor.setMaxPoolSize(maxPoolSize);        executor.setQueueCapacity(queueCapacity);        executor.setThreadNamePrefix("MySimpleExecutor-");        executor.initialize();        return executor;    }    @Bean    public Executor myAsync() {        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();        executor.setCorePoolSize(corePoolSize);        executor.setMaxPoolSize(maxPoolSize);        executor.setQueueCapacity(queueCapacity);        executor.setThreadNamePrefix("MyExecutor-");        // rejection-policy：当pool已经达到max size的时候，如何处理新任务        // CALLER_RUNS：不在新线程中执行任务，而是有调用者所在的线程来执行        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());        executor.initialize();        return executor;    }}

这里定义了两个不同的Executor，第二个重新设置了pool已经达到max size时候的处理方法；同时指定了线程名字的前缀。

2、自定义Executor的使用：

把上面自定义Executor的方法名，加入@Async注解当中。

import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.scheduling.annotation.Async;import org.springframework.scheduling.annotation.AsyncResult;import org.springframework.stereotype.Component;import java.util.Random;import java.util.concurrent.Future;/** * Created by Jiacheng on 2017/8/28. */@Componentpublic class AsyncTask {    private static Random random =new Random();    protected final Logger logger = LoggerFactory.getLogger(this.getClass());    @Async("mySimpleAsync")    public Future
    
      doTask1() throws InterruptedException{        logger.info("Task1 started.");        long start = System.currentTimeMillis();        Thread.sleep(5000);        long end = System.currentTimeMillis();        logger.info("Task1 finished, time elapsed: {} ms.", end-start);        return new AsyncResult<>("Task1 accomplished by Async-mySimpleAsync!");    }    @Async("myAsync")    public Future
     
       doTask2() throws InterruptedException{        logger.info("Task2 started.");        long start = System.currentTimeMillis();        Thread.sleep(3000);        long end = System.currentTimeMillis();        logger.info("Task2 finished, time elapsed: {} ms.", end-start);        return new AsyncResult<>("Task2 accomplished by Async-myAsync!");    }}

3、测试用例及结果：

/** * Created by Jiacheng on 2017/8/28. * * AsyncTask @Test */public class TestAsync {    protected final Logger logger = LoggerFactory.getLogger(this.getClass());    @Autowired    private AsyncTask asyncTask;    @Test    public void AsyncTaskTest() throws Exception {        asyncTask = new AsyncTask();        Future
    
      task1 = asyncTask.doTask1();        Future
     
       task2 = asyncTask.doTask2();        while(true) {            if(task1.isDone() && task2.isDone()) {                logger.info("Task1 result: {}", task1.get());                logger.info("Task2 result: {}", task2.get());                break;            }            Thread.sleep(1000);        }        logger.info("All tasks finished.");    }}

Connected to the target VM, address: '127.0.0.1:54066', transport: 'socket'[TestNG] Running:  C:\Users\Jiacheng\.IntelliJIdea2017.1\system\temp-testng-customsuite.xml16:33:34.926 [main] INFO ncu.jerry.orangeplus.async.AsyncTask - Task1 started.16:33:39.934 [main] INFO ncu.jerry.orangeplus.async.AsyncTask - Task1 finished, time elapsed: 5000 ms.16:33:39.941 [main] INFO ncu.jerry.orangeplus.async.AsyncTask - Task2 started.16:33:42.941 [main] INFO ncu.jerry.orangeplus.async.AsyncTask - Task2 finished, time elapsed: 3000 ms.16:33:42.941 [main] INFO ncu.jerry.orangeplus.async.TestAsync - Task1 result: Task1 accomplished by Async-mySimpleAsync!16:33:42.941 [main] INFO ncu.jerry.orangeplus.async.TestAsync - Task2 result: Task2 accomplished by Async-myAsync!16:33:42.941 [main] INFO ncu.jerry.orangeplus.async.TestAsync - All tasks finished.Disconnected from the target VM, address: '127.0.0.1:54066', transport: 'socket'===============================================Default SuiteTotal tests run: 1, Failures: 0, Skips: 0===============================================

可见，两个task使用了不同的自定义线程池TaskExecutor了。

源代码：

转载于:https://my.oschina.net/ljc94/blog/1525651

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