• 创建Job
• ref

创建Job

import java.util.concurrent.Future;

public interface AsyncService {

    /**
     * 多线程下载
     * 这是一个带有回调的多线程函数
     *
     * @param url 下载url
     * @param savePath 下载路径
     * @return
     */
    Future<String> downloadFileJob(String url, String savePath);
}

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

import java.util.concurrent.Future;

@Service
public class AsyncServiceImpl implements AsyncService{

    @Async
    @Override
    public Future<String> downloadFileJob(String url, String savePath) {
        // 模拟下载耗时任务
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        // 模拟完成任务后返回参数
        String result = "任务完成";
        return new AsyncResult<>(result);
    }

}

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.scheduling.annotation.EnableAsync;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

@EnableAsync
@SpringBootTest
public class ApplicationTests {

    @Autowired
    private AsyncService asyncService;

    @Test
    public void test() throws InterruptedException, ExecutionException {
        // 异步任务列表
        List<Future<String>> jobList = new ArrayList<>();

        // 多线程跑任务
        long start = System.currentTimeMillis();
        // 执行批量任务
        for (int i = 1; i <= 200; i++) {
            jobList.add(asyncService.downloadFileJob("https://xxx.com", "/temp/file/"));
        }
        // 查看整批任务是否执行完毕
        for (Future<String> job : jobList) {
            // 使用Future的isDone()方法返回该方法是否执行完成，如果异步方法全部执行完，跳出循环
            while (!job.isDone()) {
                Thread.sleep(100);// 每隔100毫秒看一下是否执行完毕了
            }
            // get()方法获取异步任务返回值
            String result = job.get();
            System.out.println("多线程执行job返回内容：" + result);
        }
        long end = System.currentTimeMillis();
        System.out.println("多线程执行总耗时：" + (end - start) / 1000 + "s");

        // 单线程跑任务
        start = System.currentTimeMillis();
        for (int i = 1; i <= 200; i++) {
            new AsyncServiceImpl().downloadFileJob("https://xxx.com", "/temp/file/");
        }
        end = System.currentTimeMillis();
        System.out.println("单线程执行总耗时：" + (end - start) / 1000 + "s");
    }

}

ref

https://blog.csdn.net/z1353095373/article/details/108225310