DeferredResult<String> deferredResult = new DeferredResult<String>(5 * 1000L);
// 設(shè)置超時(shí)事件
deferredResult.onTimeout(() -> {
    System.out.println("異步線程執(zhí)行超時(shí), 異步線程的名稱: " + Thread.currentThread().getName());
    deferredResult.setResult("異步線程執(zhí)行超時(shí)");
});

DeferredResult<String> deferredResult = new DeferredResult<String>(5 * 1000L);
// 設(shè)置異常事件
deferredResult.onError((throwable) -> {
    System.out.println("異步請(qǐng)求出現(xiàn)錯(cuò)誤，異步線程的名稱: " + Thread.currentThread().getName() + "異常: " + throwable);
    deferredResult.setErrorResult("異步線程執(zhí)行出錯(cuò)");
});

DeferredResult<String> deferredResult = new DeferredResult<String>(5 * 1000L);
// 設(shè)置完成事件
deferredResult.onCompletion(() -> {
    System.out.println("異步線程執(zhí)行完畢，異步線程的名稱: " + Thread.currentThread().getName());
});

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.context.request.async.DeferredResult;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
@RestController
public class DemoController {
    // 自定義線程池
    public static ExecutorService exec = Executors.newCachedThreadPool();
    @GetMapping("/demo")
    public DeferredResult<String> demoResult() {
        System.out.println("容器線程: " + Thread.currentThread().getName());
        // 創(chuàng)建DeferredResult對(duì)象，設(shè)置超時(shí)時(shí)長(zhǎng) 20秒
        DeferredResult<String> deferredResult = new DeferredResult<String>(5 * 1000L);
        // 設(shè)置超時(shí)事件
        deferredResult.onTimeout(() -> {
            System.out.println("異步線程執(zhí)行超時(shí), 異步線程的名稱: " + Thread.currentThread().getName());
            // throw new RuntimeException("超時(shí)事件報(bào)錯(cuò)了！");
            deferredResult.setResult("異步線程執(zhí)行超時(shí)");
        });
        // 設(shè)置異常事件
        deferredResult.onError((throwable) -> {
            System.out.println("異步請(qǐng)求出現(xiàn)錯(cuò)誤，異步線程的名稱: " + Thread.currentThread().getName() + "異常: " + throwable);
            deferredResult.setErrorResult("異步線程執(zhí)行出錯(cuò)");
        });
        // 設(shè)置完成事件
        deferredResult.onCompletion(() -> {
            System.out.println("異步線程執(zhí)行完畢，異步線程的名稱: " + Thread.currentThread().getName());
        });
        exec.execute(() -> {
            System.out.println("[線程池] 異步線程的名稱: " + Thread.currentThread().getName());
            deferredResult.setResult("異步線程執(zhí)行完畢");
        });
        System.out.println("Servlet thread release");
        return deferredResult;
    }
}

@SpringBootApplication
public class DemoApplication implements WebMvcConfigurer {
 
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

 
import com.google.common.collect.HashMultimap;
import com.google.common.collect.Multimap;
import com.google.common.collect.Multimaps;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.context.request.async.DeferredResult;
import java.util.Collection;
@RestController
public class ApolloController {
    private final Logger logger = LoggerFactory.getLogger(this.getClass());
    //guava中的Multimap，多值map,對(duì)map的增強(qiáng)，一個(gè)key可以保持多個(gè)value
    private Multimap<String, DeferredResult<String>> watchRequests = Multimaps.synchronizedSetMultimap(HashMultimap.create());
    //模擬長(zhǎng)輪詢
    @RequestMapping(value = "/watch/{namespace}", method = RequestMethod.GET, produces = "text/html")
    public DeferredResult<String> watch(@PathVariable("namespace") String namespace) {
        logger.info("Request received");
        DeferredResult<String> deferredResult = new DeferredResult<>();
        //當(dāng)deferredResult完成時(shí)（不論是超時(shí)還是異常還是正常完成），移除watchRequests中相應(yīng)的watch key
        deferredResult.onCompletion(new Runnable() {
            @Override
            public void run() {
                System.out.println("remove key:" + namespace);
                watchRequests.remove(namespace, deferredResult);
            }
        });
        watchRequests.put(namespace, deferredResult);
        logger.info("Servlet thread released");
        return deferredResult;
    }
    //模擬發(fā)布namespace配置
    @RequestMapping(value = "/publish/{namespace}", method = RequestMethod.GET, produces = "text/html")
    public Object publishConfig(@PathVariable("namespace") String namespace) {
        if (watchRequests.containsKey(namespace)) {
            Collection<DeferredResult<String>> deferredResults = watchRequests.get(namespace);
            Long time = System.currentTimeMillis();
            //通知所有watch這個(gè)namespace變更的長(zhǎng)輪訓(xùn)配置變更結(jié)果
            for (DeferredResult<String> deferredResult : deferredResults) {
                deferredResult.setResult(namespace + " changed:" + time);
            }
        }
        return "success";
    }
}

 
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.ResponseStatus;
import org.springframework.web.context.request.async.AsyncRequestTimeoutException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@ControllerAdvice
class GlobalControllerExceptionHandler {
    protected static final Logger logger = LoggerFactory.getLogger(GlobalControllerExceptionHandler.class);
    @ResponseStatus(HttpStatus.NOT_MODIFIED)//返回304狀態(tài)碼
    @ResponseBody
    @ExceptionHandler(AsyncRequestTimeoutException.class) //捕獲特定異常
    public void handleAsyncRequestTimeoutException(AsyncRequestTimeoutException e, HttpServletRequest request) {
        System.out.println("handleAsyncRequestTimeoutException");
    }
}