详解SpringBoot中异步请求的实现与并行执行

import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.AsyncConfigurer;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Executor;

@Configuration
@EnableAsync
public class AsyncConfig implements AsyncConfigurer {

    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(2);
        executor.setMaxPoolSize(5);
        executor.setQueueCapacity(100);
        executor.setThreadNamePrefix("Async-");
        executor.initialize();
        return executor;
    }
}

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

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.stream.Collectors;

@Service
public class AsyncService {

    @Async
    public CompletableFuture<String> processAsync() {
        // 模拟异步任务
        try {
            Thread.sleep(1000);
            return CompletableFuture.completedFuture("单个任务执行完成");
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            return CompletableFuture.failedFuture(e);
        }
    }

    @Async
    public CompletableFuture<String> processAsyncParallel(int taskNumber) {
        // 模拟异步任务
        try {
            Thread.sleep(1000); // 假设这是耗时操作
            return CompletableFuture.completedFuture("任务 #" + taskNumber + " 执行完成");
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            return CompletableFuture.failedFuture(e);
        }
    }

    public List<CompletableFuture<String>> executeTasksInParallel() {
        List<CompletableFuture<String>> futures = new ArrayList<>();
        for (int i = 0; i < 5; i++) {
            futures.add(processAsyncParallel(i));
        }
        return futures;
    }
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.stream.Collectors;

@RestController
public class AsyncController {

    @Autowired
    private AsyncService asyncService;

    @GetMapping("/startParallelTasks")
    public String startParallelTasks() {
        List<CompletableFuture<String>> futures = asyncService.executeTasksInParallel();

        // 等待所有任务完成
        CompletableFuture<Void> allDoneFuture = CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
                .thenApply(v -> futures.stream()
                        .map(CompletableFuture::join)
                        .collect(Collectors.toList()));

        allDoneFuture.thenAccept(results -> results.forEach(System.out::println));

        return "并行任务开始执行";
    }

    @GetMapping("/waitForSpecificTask")
    public String waitForSpecificTask() throws Exception {
        CompletableFuture<String> future = asyncService.processAsync();

        // 等待特定任务完成
        String result = future.get(); // 阻塞直到任务完成

        return "特定任务完成，结果：" + result;
    }
}