SpringBoot中使用異步方法優(yōu)化Service邏輯，提高接口響應(yīng)速度
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來自：blog.csdn.net/weixin_43441509/article/details/119855613
1. 為什么需要異步方法?
2. SpringBoot中的異步方法支持
@EnableAsync?//?使用異步方法時(shí)需要提前開啟(在啟動(dòng)類上或配置類上)
@Async?//?被async注解修飾的方法由SpringBoot默認(rèn)線程池(SimpleAsyncTaskExecutor)執(zhí)行
@Service
public?class?ArticleServiceImpl?{
????//?查詢文章
????public?String?selectArticle()?{
????????//?TODO?模擬文章查詢操作
????????System.out.println("查詢?nèi)蝿?wù)線程"+Thread.currentThread().getName());
????????return?"文章詳情";
????}
????//?文章閱讀量+1
????@Async
????public?void?updateReadCount()?{
????????//?TODO?模擬耗時(shí)操作
????????try?{
????????????Thread.sleep(3000);
????????}?catch?(InterruptedException?e)?{
????????????e.printStackTrace();
????????}
????????System.out.println("更新任務(wù)線程"+Thread.currentThread().getName());
????}
}
@RestController
public?class?AsyncTestController?{
????@Autowired
????private?ArticleServiceImpl?articleService;
????/**
?????*?模擬獲取文章后閱讀量+1
?????*/
????@PostMapping("/article")
????public?String?getArticle()?{
????????//?查詢文章
????????String?article?=?articleService.selectArticle();
????????//?閱讀量+1
????????articleService.updateReadCount();
????????System.out.println("文章閱讀業(yè)務(wù)執(zhí)行完畢");
????????return?article;
????}
}
3. 自定義線程池執(zhí)行異步方法
@EnableAsync?//?開啟多線程,?項(xiàng)目啟動(dòng)時(shí)自動(dòng)創(chuàng)建
@Configuration
public?class?AsyncConfig?{
????@Bean("customExecutor")
????public?ThreadPoolTaskExecutor?asyncOperationExecutor()?{
????????ThreadPoolTaskExecutor?executor?=?new?ThreadPoolTaskExecutor();
????????//?設(shè)置核心線程數(shù)
????????executor.setCorePoolSize(8);
????????//?設(shè)置最大線程數(shù)
????????executor.setMaxPoolSize(20);
????????//?設(shè)置隊(duì)列大小
????????executor.setQueueCapacity(Integer.MAX_VALUE);
????????//?設(shè)置線程活躍時(shí)間(秒)
????????executor.setKeepAliveSeconds(60);
????????//?設(shè)置線程名前綴+分組名稱
????????executor.setThreadNamePrefix("AsyncOperationThread-");
????????executor.setThreadGroupName("AsyncOperationGroup");
????????//?所有任務(wù)結(jié)束后關(guān)閉線程池
????????executor.setWaitForTasksToCompleteOnShutdown(true);
????????//?初始化
????????executor.initialize();
????????return?executor;
????}
}
//?文章閱讀量+1
@Async("customExecutor")
public?void?updateReadCount()?{
????//?TODO?模擬耗時(shí)操作
????try?{
????????Thread.sleep(3000);
????}?catch?(InterruptedException?e)?{
????????e.printStackTrace();
????}
????System.out.println("更新文章閱讀量線程"+Thread.currentThread().getName());
}
5. 如何捕獲(無返回值的)異步方法中的異常
@EnableAsync?//?開啟多線程,?項(xiàng)目啟動(dòng)時(shí)自動(dòng)創(chuàng)建
@Configuration
public?class?AsyncConfig?implements?AsyncConfigurer?{
????@Override
????public?Executor?getAsyncExecutor()?{
????????ThreadPoolTaskExecutor?executor?=?new?ThreadPoolTaskExecutor();
????????//?設(shè)置核心線程數(shù)
????????executor.setCorePoolSize(8);
????????//?設(shè)置最大線程數(shù)
????????executor.setMaxPoolSize(20);
????????//?設(shè)置隊(duì)列大小
????????executor.setQueueCapacity(Integer.MAX_VALUE);
????????//?設(shè)置線程活躍時(shí)間(秒)
????????executor.setKeepAliveSeconds(60);
????????//?設(shè)置線程名前綴+分組名稱
????????executor.setThreadNamePrefix("AsyncOperationThread-");
????????executor.setThreadGroupName("AsyncOperationGroup");
????????//?所有任務(wù)結(jié)束后關(guān)閉線程池
????????executor.setWaitForTasksToCompleteOnShutdown(true);
????????//?初始化
????????executor.initialize();
????????return?executor;
????}
????@Override
????public?AsyncUncaughtExceptionHandler?getAsyncUncaughtExceptionHandler()?{
????????return?new?CustomAsyncExceptionHandler();
????}
}
public?class?CustomAsyncExceptionHandler?implements?AsyncUncaughtExceptionHandler?{
?
????@Override
????public?void?handleUncaughtException(Throwable?throwable,?Method?method,?Object...?obj)?{
????????System.out.println("異常捕獲---------------------------------");
????????System.out.println("Exception?message?-?"?+?throwable.getMessage());
????????System.out.println("Method?name?-?"?+?method.getName());
????????for?(Object?param?:?obj)?{
????????????System.out.println("Parameter?value?-?"?+?param);
????????}
????????System.out.println("異常捕獲---------------------------------");
????}
?????
}
5. 如何獲取(有返回值)異步方法的返回值
無返回值的異步方法拋出異常不會(huì)影響Controller的主要業(yè)務(wù)邏輯
有返回值的異步方法拋出異常會(huì)影響Controller的主要業(yè)務(wù)邏輯
//?異步方法---------------------------------------------------------------------
@Async
????public?CompletableFuture?updateReadCountHasResult()?{
????????//?TODO?模擬耗時(shí)操作
????????try?{
????????????Thread.sleep(3000);
????????}?catch?(InterruptedException?e)?{
????????????e.printStackTrace();
????????}
????????System.out.println("更新文章閱讀量線程"+Thread.currentThread().getName());
????????return?CompletableFuture.completedFuture(100?+?1);
????}
//?Controller調(diào)用---------------------------------------------------------------------
@GetMapping("/article")
public?String?getArticle()?throws?ExecutionException,?InterruptedException?{
????//?查詢文章
????String?article?=?articleService.selectArticle();
????//?閱讀量+1
????CompletableFuture?future?=?articleService.updateReadCountHasResult();
????int?count?=?0;
????//?循環(huán)等待異步請(qǐng)求結(jié)果
????while?(true)?{
????????if(future.isCancelled())?{
????????????System.out.println("異步任務(wù)取消");
????????????break;
????????}
????????if?(future.isDone())?{
????????????count?=?future.get();
????????????System.out.println(count);
????????????break;
????????}
????}
????System.out.println("文章閱讀業(yè)務(wù)執(zhí)行完畢");
????return?article?+?count;
}
6. 異步方法帶來的問題/拓展
異步方法只能聲明在Service方法中在Controller直接調(diào)用才會(huì)生效, 異步方法被同級(jí)Service方法調(diào)用不會(huì)生效, 很奇怪?
異步方法 + 事務(wù)能順利執(zhí)行嗎? 或許事務(wù)操作應(yīng)該和異步操作分離開, 被Controller層調(diào)用時(shí)事務(wù)操作在前, 異步操作在后
異步方法執(zhí)行失敗后對(duì)Controller前半部分的非異步操作無影響, 因此說異步方法在整個(gè)業(yè)務(wù)邏輯中不是100%可靠的, 對(duì)于強(qiáng)一致性的業(yè)務(wù)來說不適用
還是消息中間件更為強(qiáng)大, RabbitMQ, Kafka…
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