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異步執(zhí)行
增加內(nèi)嵌 Tomcat 的最大連接數(shù)
使用 @ComponentScan()
默認(rèn) Tomcat 容器改為 Undertow
使用 BufferedWriter 進(jìn)行緩沖
Deferred 方式實(shí)現(xiàn)異步調(diào)用
異步調(diào)用可以使用 AsyncHandlerInterceptor 進(jìn)行攔截
異步執(zhí)行
實(shí)現(xiàn)方式二種：
使用異步注解 @aysnc、啟動(dòng)類：添加 @EnableAsync 注解
JDK 8 本身有一個(gè)非常好用的 Future 類——CompletableFuture
@AllArgsConstructor
public?class?AskThread?implements?Runnable{
????private?CompletableFuture?re?=?null;
????public?void?run()?{
????????int?myRe?=?0;
????????try?{
????????????myRe?=?re.get()?*?re.get();
????????}?catch?(Exception?e)?{
????????????e.printStackTrace();
????????}
????????System.out.println(myRe);
????}
????public?static?void?main(String[]?args)?throws?InterruptedException?{
????????final?CompletableFuture?future?=?new?CompletableFuture<>();
????????new?Thread(new?AskThread(future)).start();
????????//模擬長時(shí)間的計(jì)算過程
????????Thread.sleep(1000);
????????//告知完成結(jié)果
????????future.complete(60);
????}
}
在該示例中，啟動(dòng)一個(gè)線程，此時(shí) AskThread 對(duì)象還沒有拿到它需要的數(shù)據(jù)，執(zhí)行到? myRe = re.get() * re.get() 會(huì)阻塞。
我們用休眠 1 秒來模擬一個(gè)長時(shí)間的計(jì)算過程，并將計(jì)算結(jié)果告訴 future 執(zhí)行結(jié)果，AskThread 線程將會(huì)繼續(xù)執(zhí)行。
public?class?Calc?{
????public?static?Integer?calc(Integer?para)?{
????????try?{
????????????//模擬一個(gè)長時(shí)間的執(zhí)行
????????????Thread.sleep(1000);
????????}?catch?(InterruptedException?e)?{
????????????e.printStackTrace();
????????}
????????return?para?*?para;
????}
????public?static?void?main(String[]?args)?throws?ExecutionException,?InterruptedException?{
????????final?CompletableFuture?future?=?CompletableFuture.supplyAsync(()?->?calc(50))
????????????????.thenApply((i)?->?Integer.toString(i))
????????????????.thenApply((str)?->?"\""?+?str?+?"\"")
????????????????.thenAccept(System.out::println);
????????future.get();
????}
}
CompletableFuture.supplyAsync 方法構(gòu)造一個(gè) CompletableFuture 實(shí)例，在 supplyAsync() 方法中，它會(huì)在一個(gè)新線程中，執(zhí)行傳入的參數(shù)。
在這里它會(huì)執(zhí)行 calc() 方法，這個(gè)方法可能是比較慢的，但這并不影響 CompletableFuture 實(shí)例的構(gòu)造速度，supplyAsync() 會(huì)立即返回。
而返回的 CompletableFuture?實(shí)例就可以作為這次調(diào)用的契約，在將來任何場合，用于獲得最終的計(jì)算結(jié)果。
supplyAsync 用于提供返回值的情況，CompletableFuture 還有一個(gè)不需要返回值的異步調(diào)用方法 runAsync(Runnable runnable)，一般我們?cè)趦?yōu)化 Controller 時(shí)，使用這個(gè)方法比較多。
這兩個(gè)方法如果在不指定線程池的情況下，都是在 ForkJoinPool.common 線程池中執(zhí)行，而這個(gè)線程池中的所有線程都是 Daemon（守護(hù)）線程，所以，當(dāng)主線程結(jié)束時(shí)，這些線程無論執(zhí)行完畢都會(huì)退出系統(tǒng)。
核心代碼：
CompletableFuture.runAsync(()?->
???this.afterBetProcessor(betRequest,betDetailResult,appUser,id)
);
異步調(diào)用使用 Callable 來實(shí)現(xiàn)：
@RestController??
public?class?HelloController?{
????private?static?final?Logger?logger?=?LoggerFactory.getLogger(HelloController.class);
????@Autowired??
????private?HelloService?hello;
????@GetMapping("/helloworld")
????public?String?helloWorldController()?{
????????return?hello.sayHello();
????}
????/**
?????*?異步調(diào)用restful
?????*?當(dāng)controller返回值是Callable的時(shí)候，springmvc就會(huì)啟動(dòng)一個(gè)線程將Callable交給TaskExecutor去處理
?????*?然后DispatcherServlet還有所有的spring攔截器都退出主線程，然后把response保持打開的狀態(tài)
?????*?當(dāng)Callable執(zhí)行結(jié)束之后，springmvc就會(huì)重新啟動(dòng)分配一個(gè)request請(qǐng)求，然后DispatcherServlet就重新
?????*?調(diào)用和處理Callable異步執(zhí)行的返回結(jié)果，?然后返回視圖
?????*
?????*?@return
?????*/??
????@GetMapping("/hello")
????public?Callable?helloController()? {
????????logger.info(Thread.currentThread().getName()?+?"?進(jìn)入helloController方法");
????????Callable?callable?=?new?Callable()?{
????????????@Override??
????????????public?String?call()?throws?Exception?{
????????????????logger.info(Thread.currentThread().getName()?+?"?進(jìn)入call方法");
????????????????String?say?=?hello.sayHello();
????????????????logger.info(Thread.currentThread().getName()?+?"?從helloService方法返回");
????????????????return?say;
????????????}
????????};
????????logger.info(Thread.currentThread().getName()?+?"?從helloController方法返回");
????????return?callable;
????}
}
異步調(diào)用的方式 WebAsyncTask：
@RestController??
public?class?HelloController?{
????private?static?final?Logger?logger?=?LoggerFactory.getLogger(HelloController.class);
????@Autowired??
????private?HelloService?hello;
????????/**
?????*?帶超時(shí)時(shí)間的異步請(qǐng)求?通過WebAsyncTask自定義客戶端超時(shí)間
?????*
?????*?@return
?????*/??
????@GetMapping("/world")
????public?WebAsyncTask?worldController()? {
????????logger.info(Thread.currentThread().getName()?+?"?進(jìn)入helloController方法");
????????//?3s鐘沒返回，則認(rèn)為超時(shí)
????????WebAsyncTask?webAsyncTask?=?new?WebAsyncTask<>(3000,?new?Callable()?{
????????????@Override??
????????????public?String?call()?throws?Exception?{
????????????????logger.info(Thread.currentThread().getName()?+?"?進(jìn)入call方法");
????????????????String?say?=?hello.sayHello();
????????????????logger.info(Thread.currentThread().getName()?+?"?從helloService方法返回");
????????????????return?say;
????????????}
????????});
????????logger.info(Thread.currentThread().getName()?+?"?從helloController方法返回");
????????webAsyncTask.onCompletion(new?Runnable()?{
????????????@Override??
????????????public?void?run()?{
????????????????logger.info(Thread.currentThread().getName()?+?"?執(zhí)行完畢");
????????????}
????????});
????????webAsyncTask.onTimeout(new?Callable()?{
????????????@Override??
????????????public?String?call()?throws?Exception?{
????????????????logger.info(Thread.currentThread().getName()?+?"?onTimeout");
????????????????//?超時(shí)的時(shí)候，直接拋異常，讓外層統(tǒng)一處理超時(shí)異常
????????????????throw?new?TimeoutException("調(diào)用超時(shí)");
????????????}
????????});
????????return?webAsyncTask;
????}
????/**
?????*?異步調(diào)用，異常處理，詳細(xì)的處理流程見MyExceptionHandler類
?????*
?????*?@return
?????*/??
????@GetMapping("/exception")
????public?WebAsyncTask?exceptionController()? {
????????logger.info(Thread.currentThread().getName()?+?"?進(jìn)入helloController方法");
????????Callable?callable?=?new?Callable()?{
????????????@Override??
????????????public?String?call()?throws?Exception?{
????????????????logger.info(Thread.currentThread().getName()?+?"?進(jìn)入call方法");
????????????????throw?new?TimeoutException("調(diào)用超時(shí)!");
????????????}
????????};
????????logger.info(Thread.currentThread().getName()?+?"?從helloController方法返回");
????????return?new?WebAsyncTask<>(20000,?callable);
????}
}
增加內(nèi)嵌 Tomcat 的最大連接數(shù)
代碼如下：
@Configuration
public?class?TomcatConfig?{
????@Bean
????public?ConfigurableServletWebServerFactory?webServerFactory()?{
????????TomcatServletWebServerFactory?tomcatFactory?=?new?TomcatServletWebServerFactory();
????????tomcatFactory.addConnectorCustomizers(new?MyTomcatConnectorCustomizer());
????????tomcatFactory.setPort(8005);
????????tomcatFactory.setContextPath("/api-g");
????????return?tomcatFactory;
????}
????class?MyTomcatConnectorCustomizer?implements?TomcatConnectorCustomizer?{
????????public?void?customize(Connector?connector)?{
????????????Http11NioProtocol?protocol?=?(Http11NioProtocol)?connector.getProtocolHandler();
????????????//設(shè)置最大連接數(shù)
????????????protocol.setMaxConnections(20000);
????????????//設(shè)置最大線程數(shù)
????????????protocol.setMaxThreads(2000);
????????????protocol.setConnectionTimeout(30000);
????????}
????}
}
使用 @ComponentScan()
使用 @ComponentScan() 定位掃包比 @SpringBootApplication 掃包更快。
默認(rèn) Tomcat 容器改為 Undertow
默認(rèn) Tomcat 容器改為 Undertow（Jboss 下的服務(wù)器，Tomcat 吞吐量 5000，Undertow 吞吐量 8000）
<exclusions>
??<exclusion>
?????<groupId>org.springframework.bootgroupId>
?????<artifactId>spring-boot-starter-tomcatartifactId>
??exclusion>
exclusions>
改為：
<dependency>
??<groupId>org.springframework.bootgroupId>
??<artifactId>spring-boot-starter-undertowartifactId>
dependency>
使用 BufferedWriter 進(jìn)行緩沖
這里不給大家舉例，可自行嘗試。
Deferred 方式實(shí)現(xiàn)異步調(diào)用
代碼如下：
@RestController
public?class?AsyncDeferredController?{
????private?final?Logger?logger?=?LoggerFactory.getLogger(this.getClass());
????private?final?LongTimeTask?taskService;
????@Autowired
????public?AsyncDeferredController(LongTimeTask?taskService)?{
????????this.taskService?=?taskService;
????}
????@GetMapping("/deferred")
????public?DeferredResult?executeSlowTask()? {
????????logger.info(Thread.currentThread().getName()?+?"進(jìn)入executeSlowTask方法");
????????DeferredResult?deferredResult?=?new?DeferredResult<>();
????????//?調(diào)用長時(shí)間執(zhí)行任務(wù)
????????taskService.execute(deferredResult);
????????//?當(dāng)長時(shí)間任務(wù)中使用deferred.setResult("world");這個(gè)方法時(shí)，會(huì)從長時(shí)間任務(wù)中返回，繼續(xù)controller里面的流程
????????logger.info(Thread.currentThread().getName()?+?"從executeSlowTask方法返回");
????????//?超時(shí)的回調(diào)方法
????????deferredResult.onTimeout(new?Runnable(){
???@Override
???public?void?run()?{
????logger.info(Thread.currentThread().getName()?+?"?onTimeout");
????//?返回超時(shí)信息
????deferredResult.setErrorResult("time?out!");
???}
??});
????????//?處理完成的回調(diào)方法，無論是超時(shí)還是處理成功，都會(huì)進(jìn)入這個(gè)回調(diào)方法
????????deferredResult.onCompletion(new?Runnable(){
???@Override
???public?void?run()?{
????logger.info(Thread.currentThread().getName()?+?"?onCompletion");
???}
??});
????????return?deferredResult;
????}
}
異步調(diào)用可以使用 AsyncHandlerInterceptor 進(jìn)行攔截
代碼如下：
@Component
public?class?MyAsyncHandlerInterceptor?implements?AsyncHandlerInterceptor?{
?private?static?final?Logger?logger?=?LoggerFactory.getLogger(MyAsyncHandlerInterceptor.class);
?@Override
?public?boolean?preHandle(HttpServletRequest?request,?HttpServletResponse?response,?Object?handler)
???throws?Exception?{
??return?true;
?}
?@Override
?public?void?postHandle(HttpServletRequest?request,?HttpServletResponse?response,?Object?handler,
???ModelAndView?modelAndView)?throws?Exception?{
//?HandlerMethod?handlerMethod?=?(HandlerMethod)?handler;
??logger.info(Thread.currentThread().getName()+?"服務(wù)調(diào)用完成，返回結(jié)果給客戶端");
?}
?@Override
?public?void?afterCompletion(HttpServletRequest?request,?HttpServletResponse?response,?Object?handler,?Exception?ex)
???throws?Exception?{
??if(null?!=?ex){
???System.out.println("發(fā)生異常:"+ex.getMessage());
??}
?}
?@Override
?public?void?afterConcurrentHandlingStarted(HttpServletRequest?request,?HttpServletResponse?response,?Object?handler)
???throws?Exception?{
??//?攔截之后，重新寫回?cái)?shù)據(jù)，將原來的hello?world換成如下字符串
??String?resp?=?"my?name?is?chhliu!";
??response.setContentLength(resp.length());
??response.getOutputStream().write(resp.getBytes());
??logger.info(Thread.currentThread().getName()?+?"?進(jìn)入afterConcurrentHandlingStarted方法");
?}
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