7种方式，教你提升 SpringBoot 项目的吞吐量

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来源：xhcom.blog.csdn.net/article/details/88046026

一、异步执行

实现方式二种：

使用异步注解@aysnc、启动类：添加@EnableAsync注解
JDK 8本身有一个非常好用的Future类——CompletableFuture

@AllArgsConstructor
public class AskThread implements Runnable{private CompletableFuture<Integer> 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<Integer> future = new CompletableFuture<>();new Thread(new AskThread(future)).start();//模拟长时间的计算过程Thread.sleep(1000);//告知完成结果future.complete(60);}
}

在该示例中，启动一个线程，此时AskThread对象还没有拿到它需要的数据，执行到 myRe = re.get() * re.get()会阻塞。我们用休眠1秒来模拟一个长时间的计算过程，并将计算结果告诉future执行结果，AskThread线程将会继续执行。

public class Calc {public static Integer calc(Integer para) {try {//模拟一个长时间的执行Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}return para * para;}public static void main(String[] args) throws ExecutionException, InterruptedException {final CompletableFuture<Void> future = CompletableFuture.supplyAsync(() -> calc(50)).thenApply((i) -> Integer.toString(i)).thenApply((str) -> "\"" + str + "\"").thenAccept(System.out::println);future.get();}
}

CompletableFuture.supplyAsync方法构造一个CompletableFuture实例，在supplyAsync()方法中，它会在一个新线程中，执行传入的参数。在这里它会执行calc()方法，这个方法可能是比较慢的，但这并不影响CompletableFuture实例的构造速度，supplyAsync()会立即返回。而返回的CompletableFuture实例就可以作为这次调用的契约，在将来任何场合，用于获得最终的计算结果。

supplyAsync用于提供返回值的情况，CompletableFuture还有一个不需要返回值的异步调用方法runAsync(Runnable runnable),一般我们在优化Controller时，使用这个方法比较多。这两个方法如果在不指定线程池的情况下，都是在ForkJoinPool.common线程池中执行，而这个线程池中的所有线程都是Daemon（守护）线程，所以，当主线程结束时，这些线程无论执行完毕都会退出系统。

核心代码：

CompletableFuture.runAsync(() ->this.afterBetProcessor(betRequest,betDetailResult,appUser,id)
);

异步调用使用Callable来实现

@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();  }  /** * 异步调用restful * 当controller返回值是Callable的时候，springmvc就会启动一个线程将Callable交给TaskExecutor去处理 * 然后DispatcherServlet还有所有的spring拦截器都退出主线程，然后把response保持打开的状态 * 当Callable执行结束之后，springmvc就会重新启动分配一个request请求，然后DispatcherServlet就重新 * 调用和处理Callable异步执行的返回结果， 然后返回视图 *  * @return */  @GetMapping("/hello")  public Callable<String> helloController() {  logger.info(Thread.currentThread().getName() + " 进入helloController方法");  Callable<String> callable = new Callable<String>() {  @Override  public String call() throws Exception {  logger.info(Thread.currentThread().getName() + " 进入call方法");  String say = hello.sayHello();  logger.info(Thread.currentThread().getName() + " 从helloService方法返回");  return say;  }  };  logger.info(Thread.currentThread().getName() + " 从helloController方法返回");  return callable;  }
}

异步调用的方式 WebAsyncTask

@RestController
public class HelloController {  private static final Logger logger = LoggerFactory.getLogger(HelloController.class);  @Autowired  private HelloService hello;  /** * 带超时时间的异步请求 通过WebAsyncTask自定义客户端超时间 *  * @return */  @GetMapping("/world")  public WebAsyncTask<String> worldController() {  logger.info(Thread.currentThread().getName() + " 进入helloController方法");  // 3s钟没返回，则认为超时  WebAsyncTask<String> webAsyncTask = new WebAsyncTask<>(3000, new Callable<String>() {  @Override  public String call() throws Exception {  logger.info(Thread.currentThread().getName() + " 进入call方法");  String say = hello.sayHello();  logger.info(Thread.currentThread().getName() + " 从helloService方法返回");  return say;  }  });  logger.info(Thread.currentThread().getName() + " 从helloController方法返回");  webAsyncTask.onCompletion(new Runnable() {  @Override  public void run() {  logger.info(Thread.currentThread().getName() + " 执行完毕");  }  });  webAsyncTask.onTimeout(new Callable<String>() {  @Override  public String call() throws Exception {  logger.info(Thread.currentThread().getName() + " onTimeout");  // 超时的时候，直接抛异常，让外层统一处理超时异常  throw new TimeoutException("调用超时");  }  });  return webAsyncTask;  }  /** * 异步调用，异常处理，详细的处理流程见MyExceptionHandler类 *  * @return */  @GetMapping("/exception")  public WebAsyncTask<String> exceptionController() {  logger.info(Thread.currentThread().getName() + " 进入helloController方法");  Callable<String> callable = new Callable<String>() {  @Override  public String call() throws Exception {  logger.info(Thread.currentThread().getName() + " 进入call方法");  throw new TimeoutException("调用超时!");  }  };  logger.info(Thread.currentThread().getName() + " 从helloController方法返回");  return new WebAsyncTask<>(20000, callable);  }  }

二、增加内嵌Tomcat的最大连接数

@Configuration
public class TomcatConfig {@Beanpublic 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();//设置最大连接数               protocol.setMaxConnections(20000);//设置最大线程数               protocol.setMaxThreads(2000);protocol.setConnectionTimeout(30000);}}}

三、使用@ComponentScan()定位扫包比@SpringBootApplication扫包更快

四、默认tomcat容器改为Undertow（Jboss下的服务器，Tomcat吞吐量5000，Undertow吞吐量8000）

<exclusions><exclusion><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-tomcat</artifactId></exclusion>
</exclusions>

改为:

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-undertow</artifactId>
</dependency>

五、使用 BufferedWriter 进行缓冲

六、Deferred方式实现异步调用

@RestController
public class AsyncDeferredController {private final Logger logger = LoggerFactory.getLogger(this.getClass());private final LongTimeTask taskService;@Autowiredpublic AsyncDeferredController(LongTimeTask taskService) {this.taskService = taskService;}@GetMapping("/deferred")public DeferredResult<String> executeSlowTask() {logger.info(Thread.currentThread().getName() + "进入executeSlowTask方法");DeferredResult<String> deferredResult = new DeferredResult<>();// 调用长时间执行任务taskService.execute(deferredResult);// 当长时间任务中使用deferred.setResult("world");这个方法时，会从长时间任务中返回，继续controller里面的流程logger.info(Thread.currentThread().getName() + "从executeSlowTask方法返回");// 超时的回调方法deferredResult.onTimeout(new Runnable(){@Overridepublic void run() {logger.info(Thread.currentThread().getName() + " onTimeout");// 返回超时信息deferredResult.setErrorResult("time out!");}});// 处理完成的回调方法，无论是超时还是处理成功，都会进入这个回调方法deferredResult.onCompletion(new Runnable(){@Overridepublic void run() {logger.info(Thread.currentThread().getName() + " onCompletion");}});return deferredResult;}
}

七、异步调用可以使用AsyncHandlerInterceptor进行拦截

@Component
public class MyAsyncHandlerInterceptor implements AsyncHandlerInterceptor {private static final Logger logger = LoggerFactory.getLogger(MyAsyncHandlerInterceptor.class);@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)throws Exception {return true;}@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,ModelAndView modelAndView) throws Exception {
//  HandlerMethod handlerMethod = (HandlerMethod) handler;logger.info(Thread.currentThread().getName()+ "服务调用完成，返回结果给客户端");}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)throws Exception {if(null != ex){System.out.println("发生异常:"+ex.getMessage());}}@Overridepublic void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler)throws Exception {// 拦截之后，重新写回数据，将原来的hello world换成如下字符串String resp = "my name is chhliu!";response.setContentLength(resp.length());response.getOutputStream().write(resp.getBytes());logger.info(Thread.currentThread().getName() + " 进入afterConcurrentHandlingStarted方法");}}

参考

https://my.oschina.net/u/3768341/blog/3001731

https://blog.csdn.net/liuchuanhong1/article/details/78744138