詳解在SpringBoot如何優雅的使用多執行緒

@Configuration
@EnableAsync
public class AsyncConfiguration {
 
    @Bean("doSomethingExecutor")
    public Executor doSomethingExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        // 核心執行緒數：執行緒池建立時候初始化的執行緒數
        executor.setCorePoolSize(10);
        // 最大執行緒數：執行緒池最大的執行緒數，只有在緩衝佇列滿了之後才會申請超過核心執行緒數的執行緒
        executor.setMaxPoolSize(20);
        // 緩衝佇列：用來緩衝執行任務的佇列
        executor.setQueueCapacity(500);
        // 允許執行緒的空閒時間60秒：當超過了核心執行緒之外的執行緒在空閒時間到達之後會被銷燬
        executor.setKeepAliveSeconds(60);
        // 執行緒池名的字首：設定好了之後可以方便我們定位處理任務所在的執行緒池
        executor.setThreadNamePrefix("do-something-");
        // 緩衝佇列滿了之後的拒絕策略：由呼叫執行緒處理（一般是主執行緒）
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy());
        executor.initialize();
        return executor;
    }
 
}

@RestController
public class AsyncController {
 
    @Autowired
    private AsyncService asyncService;
 
    @GetMapping("/open/something")
    public String something() {
        int count = 10;
        for (int i = 0; i < count; i++) {
            asyncService.doSomething("index = " + i);
        }
        return "success";
    }
}
 
 
@Slf4j
@Service
public class AsyncService {
 
    // 指定使用beanname為doSomethingExecutor的執行緒池
    @Async("doSomethingExecutor")
    public String doSomething(String message) {
        log.info("do something, message={}", message);
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            log.error("do something error: ", e);
        }
        return message;
    }
}

@RestController
public class AsyncController {
 
    @Autowired
    private AsyncService asyncService;
 
    @SneakyThrows
    @ApiOperation("非同步 有返回值")
    @GetMapping("/open/somethings")
    public String somethings() {
        CompletableFuture<String> createOrder = asyncService.doSomething1("create order");
        CompletableFuture<String> reduceAccount = asyncService.doSomething2("reduce account");
        CompletableFuture<String> saveLog = asyncService.doSomething3("save log");
 
        // 等待所有任務都執行完
        CompletableFuture.allOf(createOrder, reduceAccount, saveLog).join();
        // 獲取每個任務的返回結果
        String result = createOrder.get() + reduceAccount.get() + saveLog.get();
        return result;
    }
}
 
 
@Slf4j
@Service
public class AsyncService {
 
    @Async("doSomethingExecutor")
    public CompletableFuture<String> doSomething1(String message) throws InterruptedException {
        log.info("do something1: {}", message);
        Thread.sleep(1000);
        return CompletableFuture.completedFuture("do something1: " + message);
    }
 
    @Async("doSomethingExecutor")
    public CompletableFuture<String> doSomething2(String message) throws InterruptedException {
        log.info("do something2: {}", message);
        Thread.sleep(1000);
        return CompletableFuture.completedFuture("; do something2: " + message);
    }
 
    @Async("doSomethingExecutor")
    public CompletableFuture<String> doSomething3(String message) throws InterruptedException {
        log.info("do something3: {}", message);
        Thread.sleep(1000);
        return CompletableFuture.completedFuture("; do something3: " + message);
    }
}