@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();
	}
	/**
	 * 異步調用restful
	 * 當controller返回值是Callable的時候，springmvc就會啟動一個線程將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Callable執(zhí)行結束之后，springmvc就會重新啟動分配一個request請求，然后DispatcherServlet就重新
	 * 調用和處理Callable異步執(zhí)行的返回結果， 然后返回視圖
	 * 
	 * @return
	 */
	@GetMapping("/hello")
	public Callable<String> helloController() {
		logger.info(Thread.currentThread().getName() + " 進入helloController方法");
		Callable<String> callable = new Callable<String>() {
			@Override
			public String call() throws Exception {
				logger.info(Thread.currentThread().getName() + " 進入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;
	}
}

@RestController
public class HelloController {
	private static final Logger logger = LoggerFactory.getLogger(HelloController.class);
	@Autowired
	private HelloService hello;
		/**
	 * 帶超時時間的異步請求 通過WebAsyncTask自定義客戶端超時間
	 * 
	 * @return
	 */
	@GetMapping("/world")
	public WebAsyncTask<String> worldController() {
		logger.info(Thread.currentThread().getName() + " 進入helloController方法");
		// 3s鐘沒返回，則認為超時
		WebAsyncTask<String> webAsyncTask = new WebAsyncTask<>(3000, new Callable<String>() {
			@Override
			public String call() throws Exception {
				logger.info(Thread.currentThread().getName() + " 進入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<String>() {
			@Override
			public String call() throws Exception {
				logger.info(Thread.currentThread().getName() + " onTimeout");
				// 超時的時候，直接拋異常，讓外層統(tǒng)一處理超時異常
				throw new TimeoutException("調用超時");
			}
		});
		return webAsyncTask;
	}
	/**
	 * 異步調用，異常處理，詳細的處理流程見MyExceptionHandler類
	 * 
	 * @return
	 */
	@GetMapping("/exception")
	public WebAsyncTask<String> exceptionController() {
		logger.info(Thread.currentThread().getName() + " 進入helloController方法");
		Callable<String> callable = new Callable<String>() {
			@Override
			public String call() throws Exception {
				logger.info(Thread.currentThread().getName() + " 進入call方法");
				throw new TimeoutException("調用超時!");
			}
		};
		logger.info(Thread.currentThread().getName() + " 從helloController方法返回");
		return new WebAsyncTask<>(20000, callable);
	}
}

@Component
public class LongTimeTask {
	private final Logger logger = LoggerFactory.getLogger(this.getClass());
	@Async
	public void execute(DeferredResult<String> deferred){
		logger.info(Thread.currentThread().getName() + "進入 taskService 的 execute方法");
		try {
			// 模擬長時間任務調用，睡眠2s
			TimeUnit.SECONDS.sleep(2);
			// 2s后給Deferred發(fā)送成功消息，告訴Deferred，我這邊已經處理完了，可以返回給客戶端了
			deferred.setResult("world");
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

@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<String> executeSlowTask() {
        logger.info(Thread.currentThread().getName() + "進入executeSlowTask方法");
        DeferredResult<String> deferredResult = new DeferredResult<>();
        // 調用長時間執(zhí)行任務
        taskService.execute(deferredResult);
        // 當長時間任務中使用deferred.setResult("world");這個方法時，會從長時間任務中返回，繼續(xù)controller里面的流程
        logger.info(Thread.currentThread().getName() + "從executeSlowTask方法返回");
        // 超時的回調方法
        deferredResult.onTimeout(new Runnable(){
			@Override
			public void run() {
				logger.info(Thread.currentThread().getName() + " onTimeout");
				// 返回超時信息
				deferredResult.setErrorResult("time out!");
			}
		});
        // 處理完成的回調方法，無論是超時還是處理成功，都會進入這個回調方法
        deferredResult.onCompletion(new Runnable(){
			@Override
			public void run() {
				logger.info(Thread.currentThread().getName() + " onCompletion");
			}
		});
        return deferredResult;
    }
}

@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()+ "服務調用完成，返回結果給客戶端");
	}
	@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，重新寫回數據，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() + " 進入afterConcurrentHandlingStarted方法");
	}
}