SpringBoot多线程异步任务

需求

在 SpringBoot 项目中，一个任务比较复杂，执行时间比较长，需要采用 多线程异步 的方式执行，从而缩短任务执行时间。

多线程异步

将任务拆分成多个独立的子任务，每个子任务在独立子线程中执行；
当所有子任务的子线程全部执行完成后，将几个子任务汇总，得到总任务的执行结果。

解决方案

ThreadPoolTaskExecutor + CompletableFuture

ThreadPoolTaskExecutor：是Spring框架提供的。
CompletableFuture：是 java 提供的。

代码实现

异步任务和同步任务

package com.example.async.service;

import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.stereotype.Service;

@Service
public class TaskService {

	@Autowired
	private ThreadPoolTaskExecutor executor;

	/**
	 * 执行异步任务
	 * 
	 * @throws ExecutionException
	 * @throws InterruptedException
	 */
	public void executeAsync() throws InterruptedException, ExecutionException {
		System.out.println("----------执行异步任务，开始----------");

		long start = System.currentTimeMillis();
		CompletableFuture<Void> task1Future = CompletableFuture.runAsync(() -> {
			task1();
		}, executor);

		CompletableFuture<Void> task2Future = CompletableFuture.runAsync(() -> {
			task2();
		}, executor);

		CompletableFuture<Void> task3Future = CompletableFuture.runAsync(() -> {
			task3();
		}, executor);

		CompletableFuture.allOf(task1Future, task2Future, task3Future).get();

		long end = System.currentTimeMillis();

		System.out.println("----------执行异步任务，结束----------");
		System.out.println("执行时间：" + (end - start) + " 毫秒");
	}

	/**
	 * 执行同步任务
	 */
	public void executeSync() {
		System.out.println("----------执行同步任务，开始----------");

		long start = System.currentTimeMillis();
		task1();
		task2();
		task3();
		long end = System.currentTimeMillis();

		System.out.println("----------执行同步任务，结束----------");
		System.out.println("执行时间：" + (end - start) + " 毫秒");
	}

	private void task1() {
		try {
			System.out.println("task1 开始");
			long start = System.currentTimeMillis();
			Thread.sleep(1000);
			long end = System.currentTimeMillis();
			System.out.println("task1 结束，执行时间：" + (end - start) + " 毫秒");
		} catch (InterruptedException e) {
			throw new RuntimeException(e);
		}
	}

	private void task2() {
		try {
			System.out.println("task2 开始");
			long start = System.currentTimeMillis();
			Thread.sleep(2000);
			long end = System.currentTimeMillis();
			System.out.println("task2 结束，执行时间：" + (end - start) + " 毫秒");
		} catch (InterruptedException e) {
			throw new RuntimeException(e);
		}
	}

	private void task3() {
		try {
			System.out.println("task3 开始");
			long start = System.currentTimeMillis();
			Thread.sleep(3000);
			long end = System.currentTimeMillis();
			System.out.println("task3 结束，执行时间：" + (end - start) + " 毫秒");
		} catch (InterruptedException e) {
			throw new RuntimeException(e);
		}
	}

}

执行任务（异步任务和同步任务）

package com.example.async.controller;

import java.util.concurrent.ExecutionException;

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.example.async.service.TaskService;

@RestController
@RequestMapping("test")
public class TaskController {

	@Autowired
	private TaskService service;

	@GetMapping("async")
	public String async() {
		// 异步执行任务
		try {
			service.executeAsync();
		} catch (InterruptedException e) {
			e.printStackTrace();
		} catch (ExecutionException e) {
			e.printStackTrace();
		}
		return "异步任务已完成！";
	}

	@GetMapping("sync")
	public String sync() {
		// 同步执行任务
		service.executeSync();
		return "同步任务已完成！";
	}

}