使用Hystrix时，下面的情况会触发fallback：
下面对这四种情况做简单的验证
<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-hystrix</artifactId> <version>1.4.6.RELEASE</version></dependency>点击这里可查询最新的spring-cloud-starter-hystrix版本
package com.rambo.hystrixtest;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.netflix.hystrix.EnableHystrix;@SpringBootApplication@EnableHystrixpublic class HystrixtestApplication { public static void main(String[] args) { SpringApplication.run(HystrixtestApplication.class, args); }}1、验证异常触发fallback
package com.rambo.hystrixtest.degrade.command;import com.netflix.hystrix.HystrixCommand;import com.netflix.hystrix.HystrixCommandGroupKey;import org.slf4j.Logger;import org.slf4j.LoggerFactory;/** * 异常降级 * **非HystrixBadRequestException异常：当抛出HystrixBadRequestException时， * **调用程序可以捕获异常，此时不会触发fallback，而其他异常则会触发fallback， * **调用程序将获得fallback逻辑的返回结果。 */public class HelloWorldExceptionCommand extends HystrixCommand<String> { private final static Logger logger = LoggerFactory.getLogger(HelloWorldExceptionCommand.class); private final int n; public HelloWorldExceptionCommand(int n) { // 最小配置,指定groupKey super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("helloWorldExceptionGroup"))); this.n = n; } @Override protected String run() throws Exception { logger.info(n + "-HelloWorldExceptionCommand A--> " + Thread.currentThread().getName()); // 制造异常 int i = 1 / n; // 如果此处异常被捕获，将不会进入getFallback() /* try { int i = 1 / n; } catch (Exception e) { logger.error("异常:" + e.getMessage()); } */ logger.info(n + "-HelloWorldExceptionCommand B--> " + Thread.currentThread().getName()); return n + "执行成功"; } @Override protected String getFallback() { logger.error(n + "-异常降级! C--> " + Thread.currentThread().getName()); return n + "执行失败"; } public static void main(String[] args) throws Exception { for (int i = 0; i < Integer.MAX_VALUE; i++) { if (i == 3) { i = 0; } HelloWorldExceptionCommand command = new HelloWorldExceptionCommand(i); logger.info(command.execute()); Thread.sleep(1000); } }}执行结果如下：
16:41:22.493 [hystrix-helloWorldExceptionGroup-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 0-HelloWorldExceptionCommand A--> hystrix-helloWorldExceptionGroup-116:41:22.496 [hystrix-helloWorldExceptionGroup-1] DEBUG com.netflix.hystrix.AbstractCommand - Error executing HystrixCommand.run(). Proceeding to fallback logic ...java.lang.ArithmeticException: / by zero at com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand.run(HelloWorldExceptionCommand.java:29) at com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand.run(HelloWorldExceptionCommand.java:14) at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:302) at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:298) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OperatorSubscribeOn$SubscribeOnSubscriber.call(OperatorSubscribeOn.java:100) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:56) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:47) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69) at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)16:41:22.500 [hystrix-helloWorldExceptionGroup-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 0-异常降级! C--> hystrix-helloWorldExceptionGroup-116:41:22.504 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 0执行失败16:41:23.505 [hystrix-helloWorldExceptionGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 1-HelloWorldExceptionCommand A--> hystrix-helloWorldExceptionGroup-216:41:23.505 [hystrix-helloWorldExceptionGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 1-HelloWorldExceptionCommand B--> hystrix-helloWorldExceptionGroup-216:41:23.506 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 1执行成功16:41:24.508 [hystrix-helloWorldExceptionGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 2-HelloWorldExceptionCommand A--> hystrix-helloWorldExceptionGroup-316:41:24.508 [hystrix-helloWorldExceptionGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 2-HelloWorldExceptionCommand B--> hystrix-helloWorldExceptionGroup-316:41:24.508 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 2执行成功16:41:25.508 [hystrix-helloWorldExceptionGroup-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 0-HelloWorldExceptionCommand A--> hystrix-helloWorldExceptionGroup-416:41:25.508 [hystrix-helloWorldExceptionGroup-4] DEBUG com.netflix.hystrix.AbstractCommand - Error executing HystrixCommand.run(). Proceeding to fallback logic ...java.lang.ArithmeticException: / by zero at com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand.run(HelloWorldExceptionCommand.java:29) at com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand.run(HelloWorldExceptionCommand.java:14) at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:302) at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:298) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10327) at rx.internal.operators.OperatorSubscribeOn$SubscribeOnSubscriber.call(OperatorSubscribeOn.java:100) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:56) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:47) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69) at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)16:41:25.508 [hystrix-helloWorldExceptionGroup-4] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 0-异常降级! C--> hystrix-helloWorldExceptionGroup-416:41:25.509 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 0执行失败16:41:26.511 [hystrix-helloWorldExceptionGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 1-HelloWorldExceptionCommand A--> hystrix-helloWorldExceptionGroup-516:41:26.511 [hystrix-helloWorldExceptionGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 1-HelloWorldExceptionCommand B--> hystrix-helloWorldExceptionGroup-516:41:26.511 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 1执行成功2、验证超时触发fallback
package com.rambo.hystrixtest.degrade.command;import com.netflix.hystrix.HystrixCommand;import com.netflix.hystrix.HystrixCommandGroupKey;import com.netflix.hystrix.HystrixCommandProperties;import org.slf4j.Logger;import org.slf4j.LoggerFactory;/** * 超时降级 * **run()/construct()运行超时：执行命令的方法超时，将会触发fallback。 */public class HelloWorldTimeoutCommand extends HystrixCommand<String> { private final static Logger logger = LoggerFactory.getLogger(HelloWorldTimeoutCommand.class); private final int n; public HelloWorldTimeoutCommand(int n) { super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("helloWorldTimeoutGroup")) .andCommandPropertiesDefaults(HystrixCommandProperties.Setter() /* * execution.isolation.thread.timeoutInMilliseconds * 设置调用者等待命令执行的超时限制，超过此时间，HystrixCommand被标记为TIMEOUT， * 并执行回退逻辑。 * 默认值：1000（毫秒） */ .withExecutionTimeoutInMilliseconds(500) /* * execution.timeout.enabled * 设置HystrixCommand的执行是否有超时限制。 * 默认值：true */ .withExecutionTimeoutEnabled(true) /* * execution.isolation.thread.interruptOnTimeout * 设置HystrixCommand的执行是否在超时发生时被中断。 * 使用线程隔离时，是否对命令执行超时的线程调用中断（Thread.interrupt()）操作。 * 默认值：true */ .withExecutionIsolationThreadInterruptOnTimeout(false) ) ); this.n = n; } @Override protected String run() throws Exception { logger.info(n + "-HelloWorldTimeoutCommand A--> " + Thread.currentThread().getName()); if (n == 0) { // 设置超时 Thread.sleep(1000); } // 设置withExecutionIsolationThreadInterruptOnTimeout(false)后面代码将会继续执行 logger.info(n + "-HelloWorldTimeoutCommand B--> " + Thread.currentThread().getName()); return n + "执行成功"; } @Override protected String getFallback() { logger.error("超时降级! C--> " + Thread.currentThread().getName()); return n + "执行失败"; } public static void main(String[] args) throws Exception { for (int i = 0; i < Integer.MAX_VALUE; i++) { if (i == 5) { i = 0; } HelloWorldTimeoutCommand command = new HelloWorldTimeoutCommand(i); // 超时执行getFallback logger.info(command.execute()); Thread.sleep(1000); } }}执行结果如下：
16:09:25.408 [hystrix-helloWorldTimeoutGroup-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-116:09:25.906 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 超时降级! C--> HystrixTimer-116:09:25.913 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0执行失败16:09:26.410 [hystrix-helloWorldTimeoutGroup-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-116:09:26.914 [hystrix-helloWorldTimeoutGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-216:09:26.914 [hystrix-helloWorldTimeoutGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-216:09:26.914 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1执行成功16:09:27.915 [hystrix-helloWorldTimeoutGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-316:09:27.915 [hystrix-helloWorldTimeoutGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-316:09:27.915 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2执行成功16:09:28.917 [hystrix-helloWorldTimeoutGroup-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-416:09:29.418 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 超时降级! C--> HystrixTimer-116:09:29.419 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0执行失败16:09:29.917 [hystrix-helloWorldTimeoutGroup-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-416:09:30.421 [hystrix-helloWorldTimeoutGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-516:09:30.421 [hystrix-helloWorldTimeoutGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-516:09:30.421 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1执行成功16:09:31.423 [hystrix-helloWorldTimeoutGroup-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-616:09:31.423 [hystrix-helloWorldTimeoutGroup-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-616:09:31.423 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2执行成功16:09:32.425 [hystrix-helloWorldTimeoutGroup-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-716:09:32.926 [HystrixTimer-4] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 超时降级! C--> HystrixTimer-416:09:32.926 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0执行失败16:09:33.426 [hystrix-helloWorldTimeoutGroup-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-716:09:33.927 [hystrix-helloWorldTimeoutGroup-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-816:09:33.927 [hystrix-helloWorldTimeoutGroup-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-816:09:33.928 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1执行成功16:09:34.929 [hystrix-helloWorldTimeoutGroup-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-916:09:34.929 [hystrix-helloWorldTimeoutGroup-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-916:09:34.929 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2执行成功16:09:35.930 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-1016:09:36.431 [HystrixTimer-3] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 超时降级! C--> HystrixTimer-316:09:36.432 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0执行失败16:09:36.930 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 0-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-1016:09:37.433 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-1016:09:37.433 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-1016:09:37.433 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1执行成功16:09:38.435 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-1016:09:38.435 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-1016:09:38.435 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2执行成功3、验证熔断器开启触发fallback
package com.rambo.hystrixtest.degrade.command;import com.netflix.hystrix.*;import org.slf4j.Logger;import org.slf4j.LoggerFactory;/** * 触发熔断器熔断 * **熔断器开启：当熔断器处于开启的状态，将会触发fallback。 */public class HelloWorldBreakerCommand extends HystrixCommand<String> { private final static Logger logger = LoggerFactory.getLogger(HelloWorldBreakerCommand.class); private final int n; public HelloWorldBreakerCommand(int n) { //最小配置,指定groupKey super(Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("helloWorldBreakerGroup")) .andCommandPropertiesDefaults( HystrixCommandProperties.Setter() /* * execution.isolation.thread.timeoutInMilliseconds * 设置调用者等待命令执行的超时限制，超过此时间，HystrixCommand被标记为TIMEOUT， * 并执行回退逻辑。 * 默认值：1000（毫秒） */ .withExecutionTimeoutInMilliseconds(1000) /* * execution.isolation.thread.interruptOnTimeout * 设置HystrixCommand的执行是否在超时发生时被中断。 * 使用线程隔离时，是否对命令执行超时的线程调用中断（Thread.interrupt()）操作。 * 默认值：true */ .withExecutionIsolationThreadInterruptOnTimeout(true) // ** 断路器（Circuit Breaker）属性配置 ** /* * circuitBreaker.enabled * 设置断路器是否生效 * 默认值：true */ .withCircuitBreakerEnabled(true) /* * circuitBreaker.requestVolumeThreshold * 设置在一个滚动窗口中，打开断路器的最少请求数。比如：如果值是20，在一个窗口内（比如10秒），收到19个请求，即使这19个请求都失败了，断路器也不会打开。 * 默认值：20 */ .withCircuitBreakerRequestVolumeThreshold(6) /* * circuitBreaker.sleepWindowInMilliseconds * 设置在断路器被打开，拒绝请求到再次尝试请求的时间间隔。 * 默认值：5000（毫秒） */ .withCircuitBreakerSleepWindowInMilliseconds(3000) /* * circuitBreaker.errorThresholdPercentage * 设置打开断路器并启动回退逻辑的错误比率。 * （这个参数的效果受到circuitBreaker.requestVolumeThreshold和滚动时间窗口的时间长度影响） * 默认值：50(%) */ .withCircuitBreakerErrorThresholdPercentage(50) ) //设置核心线程池的大小 .andThreadPoolPropertiesDefaults(HystrixThreadPoolProperties.Setter().withCoreSize(20)) ); this.n = n; } @Override protected String run() throws Exception { logger.info(n + "-HelloWorldTimeoutCommand A--> " + Thread.currentThread().getName()); if (n > 0) { // 设置超时 Thread.sleep(1000); } // 设置withExecutionIsolationThreadInterruptOnTimeout(true)后面代码将中断执行 logger.info(n + "-HelloWorldTimeoutCommand B--> " + Thread.currentThread().getName()); return n + "执行成功"; } @Override protected String getFallback() { logger.error("熔断降级! C--> " + Thread.currentThread().getName()); return n + "执行失败"; } public static void main(String[] args) throws Exception { for (int i = 0; i < Integer.MAX_VALUE; i++) { try { if (i == 10) { i = 0; Thread.sleep(1000); } logger.info(new HelloWorldBreakerCommand(i).execute()); } catch (Exception e) { logger.error("异常:" + e.getMessage(), e); } } }}执行结果如下：
16:35:36.190 [hystrix-helloWorldBreakerGroup-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-116:35:36.190 [hystrix-helloWorldBreakerGroup-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-116:35:36.193 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0执行成功16:35:36.194 [hystrix-helloWorldBreakerGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-216:35:37.195 [hystrix-helloWorldBreakerGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-216:35:37.201 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-116:35:37.202 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1执行失败16:35:37.203 [hystrix-helloWorldBreakerGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 2-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-316:35:38.203 [hystrix-helloWorldBreakerGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-316:35:38.203 [HystrixTimer-2] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-216:35:38.204 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 2执行失败16:35:38.205 [hystrix-helloWorldBreakerGroup-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 3-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-416:35:39.205 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-116:35:39.205 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 3执行失败16:35:39.206 [hystrix-helloWorldBreakerGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 4-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-516:35:40.206 [hystrix-helloWorldBreakerGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 4-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-516:35:40.206 [HystrixTimer-3] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-316:35:40.206 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 4执行失败16:35:40.207 [hystrix-helloWorldBreakerGroup-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 5-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-616:35:41.207 [hystrix-helloWorldBreakerGroup-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 5-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-616:35:41.207 [HystrixTimer-2] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-216:35:41.208 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 5执行失败16:35:41.209 [hystrix-helloWorldBreakerGroup-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 6-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-716:35:42.210 [hystrix-helloWorldBreakerGroup-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 6-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-716:35:42.211 [HystrixTimer-4] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-416:35:42.212 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 6执行失败16:35:42.213 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:42.213 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 7执行失败16:35:42.213 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:42.214 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 8执行失败16:35:42.214 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:42.214 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 9执行失败16:35:43.215 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.215 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0执行失败16:35:43.215 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.215 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1执行失败16:35:43.216 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.216 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 2执行失败16:35:43.216 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.216 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 3执行失败16:35:43.216 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.216 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 4执行失败16:35:43.216 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.216 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 5执行失败16:35:43.216 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.216 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 6执行失败16:35:43.216 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.216 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 7执行失败16:35:43.217 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.217 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 8执行失败16:35:43.217 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:43.217 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 9执行失败16:35:44.218 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.218 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0执行失败16:35:44.218 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.218 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1执行失败16:35:44.218 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.218 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 2执行失败16:35:44.218 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.218 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 3执行失败16:35:44.218 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.218 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 4执行失败16:35:44.219 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.219 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 5执行失败16:35:44.219 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.219 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 6执行失败16:35:44.219 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.219 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 7执行失败16:35:44.219 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.219 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 8执行失败16:35:44.219 [main] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> main16:35:44.219 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 9执行失败16:35:45.220 [hystrix-helloWorldBreakerGroup-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-816:35:45.220 [hystrix-helloWorldBreakerGroup-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-816:35:45.225 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0执行成功16:35:45.226 [hystrix-helloWorldBreakerGroup-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-916:35:46.227 [hystrix-helloWorldBreakerGroup-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-916:35:46.227 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-116:35:46.228 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1执行失败16:35:46.229 [hystrix-helloWorldBreakerGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 2-HelloWorldTimeoutCommand A--> hystrix-helloWorldBreakerGroup-1016:35:47.229 [HystrixTimer-3] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-316:35:47.230 [main] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 2执行失败4、验证线程池/信号量已满触发fallback
package com.rambo.hystrixtest.degrade.command;import com.netflix.hystrix.*;import org.slf4j.Logger;import org.slf4j.LoggerFactory;/** * 线程池/信号量已满 * **当线程池/信号量已满的状态，将会触发fallback。 */public class HelloWorldThreadPoolCommand extends HystrixCommand<String> { private final static Logger logger = LoggerFactory.getLogger(HelloWorldThreadPoolCommand.class); private final int n; public HelloWorldThreadPoolCommand(int n) { super(Setter // *** 基础属性配置 *** /* * CommandGroup是每个命令最少配置的必选参数，在不指定ThreadPoolKey的情况下， * 字面值用于对不同依赖的线程池/信号区分，也就是在不指定ThreadPoolKey的情况下, * CommandGroup用于指定线程池的隔离。命令分组用于对依赖操作分组，便于统计、汇总等。 */ .withGroupKey(HystrixCommandGroupKey.Factory.asKey("helloWorldThreadPoolGroup")) /* * CommandKey是作为依赖命名，一般来说每个CommandKey代表一个依赖抽象， * 相同的依赖要使用相同的CommandKey名称。依赖隔离的根本就是对相同CommandKey的依赖做隔离。 * 不同的依赖隔离最好使用不同的线程池（定义不同的ThreadPoolKey）。 * 从HystrixCommand源码的注释也可以看到CommandKey也用于对依赖操作统计、汇总等。 */ .andCommandKey(HystrixCommandKey.Factory.asKey("helloWorldThreadPoolCommand")) /* * ThreadPoolKey简单来说就是依赖隔离使用的线程池的键值。 * 当对同一业务依赖做隔离时使用CommandGroup做区分， * 但是对同一依赖的不同远程调用如(一个是redis 一个是http)，可以使用HystrixThreadPoolKey做隔离区分。 * 虽然在业务上都是相同的组，但是需要在资源上做隔离时，可以使用HystrixThreadPoolKey区分。 * （对于每个不同的HystrixThreadPoolKey建议使用不同的CommandKey） */ .andThreadPoolKey(HystrixThreadPoolKey.Factory.asKey("helloWorldThreadPool")) // *** 设置命令属性配置默认值 *** .andCommandPropertiesDefaults( HystrixCommandProperties.Setter() // ** 执行属性 ** /* * execution.isolation.strategy * 用于设置HystrixCommand执行的隔离策略，有两种选项： * THREAD —— 在固定大小线程池中，以单独线程执行，并发请求数受限于线程池大小。 * SEMAPHORE —— 在调用线程中执行，通过信号量来限制并发量。 * 默认值：THREAD（ExecutionIsolationStrategy.THREAD）可选值：THREAD，SEMAPHORE */ .withExecutionIsolationStrategy(HystrixCommandProperties.ExecutionIsolationStrategy.THREAD) /* * execution.isolation.thread.timeoutInMilliseconds * 设置调用者等待命令执行的超时限制，超过此时间，HystrixCommand被标记为TIMEOUT， * 并执行回退逻辑。 * 默认值：1000（毫秒） */ .withExecutionTimeoutInMilliseconds(1000) /* * execution.timeout.enabled * 设置HystrixCommand的执行是否有超时限制。 * 默认值：true */ .withExecutionTimeoutEnabled(false) /* * execution.isolation.thread.interruptOnTimeout * 设置HystrixCommand的执行是否在超时发生时被中断。 * 使用线程隔离时，是否对命令执行超时的线程调用中断（Thread.interrupt()）操作。 * 默认值：true */ .withExecutionIsolationThreadInterruptOnTimeout(true) /* * execution.isolation.semaphore.maxConcurrentRequests * 设置当使用ExecutionIsolationStrategy.SEMAPHORE时，HystrixCommand执行方法允许的最大请求数。 * 如果达到最大并发数时，后续请求会被拒绝。 * 信号量应该是容器（比如Tomcat）线程池一小部分，不能等于或者略小于容器线程池大小，否则起不到保护作用。 * 默认值：10 */ .withExecutionIsolationSemaphoreMaxConcurrentRequests(10) // ** 回退属性 ** // 下面的属性控制HystrixCommand.getFallback()执行。 // 这些属性对ExecutionIsolationStrategy.THREAD和ExecutionIsolationStrategy.SEMAPHORE都有效。 /* * fallback.isolation.semaphore.maxConcurrentRequests * 设置调用线程产生的HystrixCommand.getFallback()方法的允许最大请求数目。 * 如果达到最大并发数目，后续请求将会被拒绝，如果没有实现回退，则抛出异常。 * (这里需要注意一点，这个变量的命名不是很规范，它实际上对THREAD和SEMAPHORE两种隔离策略都生效) * 默认值：10 */ .withFallbackIsolationSemaphoreMaxConcurrentRequests(10) /* * fallback.enabled * 该属性决定当前的调用故障或者拒绝发生时，是否调用HystrixCommand.getFallback()。 * 默认值：true */ .withFallbackEnabled(true) // ** 断路器（Circuit Breaker）属性配置 ** /* * circuitBreaker.enabled * 设置断路器是否生效 * 默认值：true */ .withCircuitBreakerEnabled(true) /* * circuitBreaker.requestVolumeThreshold * 设置在一个滚动窗口中，打开断路器的最少请求数。比如：如果值是20，在一个窗口内（比如10秒），收到19个请求，即使这19个请求都失败了，断路器也不会打开。 * 默认值：20 */ .withCircuitBreakerRequestVolumeThreshold(5) /* * circuitBreaker.sleepWindowInMilliseconds * 设置在断路器被打开，拒绝请求到再次尝试请求的时间间隔。 * 默认值：5000（毫秒） */ .withCircuitBreakerSleepWindowInMilliseconds(5000) /* * circuitBreaker.errorThresholdPercentage * 设置打开断路器并启动回退逻辑的错误比率。 * （这个参数的效果受到circuitBreaker.requestVolumeThreshold和滚动时间窗口的时间长度影响） * 默认值：50(%) */ .withCircuitBreakerErrorThresholdPercentage(50) /* * circuitBreaker.forceOpen * 如果该属性设置为true，强制断路器进入打开状态，将会拒绝所有的请求。 * 该属性优先级比circuitBreaker.forceClosed高 * 默认值：false */ .withCircuitBreakerForceOpen(false) /* * circuitBreaker.forceClosed * 如果该属性设置为true，强制断路器进入关闭状态，将会允许所有的请求，无视错误率。 * 默认值：false */ .withCircuitBreakerForceClosed(false) // ** 请求上下文属性配置 ** /* * requestCache.enabled * 设置HystrixCommand.getCacheKey()是否启用，由HystrixRequestCache通过请求缓存提供去重复数据功能。 * （请求结果缓存需要配合HystrixRequestContext使用，具体应用可以自行查阅） * 默认值：true */ .withRequestCacheEnabled(true) /* * requestLog.enabled * 设置HystrixCommand执行和事件是否要记录日志到HystrixRequestLog。 * 默认值：true */ .withRequestLogEnabled(true) ) // *** 设置线程池属性配置默认值 *** .andThreadPoolPropertiesDefaults( HystrixThreadPoolProperties.Setter() /* * coreSize * 设置核心线程池的大小（这个值和ThreadPoolExecutor的coreSize的含义不一样） * 默认值：10 */ .withCoreSize(10) /* * maximumSize * 1.5.9新增属性，设置线程池最大值。 * 这个是在不开始拒绝HystrixCommand的情况下支持的最大并发数。 * 这个属性起作用的前提是设置了allowMaximumSizeToDivergeFromCoreSize。 * 1.5.9之前，核心线程池大小和最大线程池大小总是相同的。 * 默认值：10 */ .withMaximumSize(10) /* * maxQueueSize * 设置BlockingQueue最大的队列值。如果设置为-1， * 那么使用SynchronousQueue，否则正数将会使用LinkedBlockingQueue。 * 如果需要去除这些限制，允许队列动态变化，可以参考queueSizeRejectionThreshold属性。 * 修改SynchronousQueue和LinkedBlockingQueue需要重启。 * 默认值：-1 */ .withMaxQueueSize(-1) /* * queueSizeRejectionThreshold * 设置队列拒绝的阈值—-一个人为设置的拒绝访问的最大队列值，即使当前队列元素还没达到maxQueueSize。 * 当将一个线程放入队列等待执行时，HystrixCommand使用该属性。 * 注意：如果maxQueueSize设置为-1，该属性不可用。 * 默认值：5 */ .withQueueSizeRejectionThreshold(5) /* * keepAliveTimeMinutes * 设置存活时间，单位分钟。如果coreSize小于maximumSize，那么该属性控制一个线程从实用完成到被释放的时间。 * 默认值：1 */ .withKeepAliveTimeMinutes(1) /* * allowMaximumSizeToDivergeFromCoreSize * 在1.5.9中新增的属性。该属性允许maximumSize起作用。属性值可以等于或者大于coreSize值， * 设置coreSize小于maximumSize的线程池能够支持maximumSize的并发数， * 但是会将不活跃的线程返回到系统中去。 * 默认值：false */ .withAllowMaximumSizeToDivergeFromCoreSize(false) /* * metrics.rollingStats.timeInMilliseconds * 设置统计的滚动窗口的时间段大小。该属性是线程池保持指标时间长短。 * 默认值：10000（毫秒） */ .withMetricsRollingStatisticalWindowInMilliseconds(10000) /* * metrics.rollingStats.numBuckets * 设置滚动的统计窗口被分成的桶（bucket）的数目。 * 注意：”metrics.rollingStats.timeInMilliseconds % metrics.rollingStats.numBuckets == 0”必须为true，否则会抛出异常。 * 默认值：10 */ .withMetricsRollingStatisticalWindowBuckets(10) ) ); this.n = n; } @Override protected String run() throws Exception { logger.info(n + "-HelloWorldThreadPoolCommand A--> " + Thread.currentThread().getName()); Thread.sleep(10000); logger.info(n + "-HelloWorldThreadPoolCommand B--> " + Thread.currentThread().getName()); return n + "执行完毕"; } @Override protected String getFallback() { logger.error("线程池/信号量已满 FALLBACK --> !"); return "FALLBACK"; } public static class ThreadRunner extends Thread { private int i; public ThreadRunner(int i) { this.i = i; } @Override public void run() { logger.info(new HelloWorldThreadPoolCommand(i).execute()); } } public static void main(String[] args) throws Exception { // 关闭HystrixCommand执行的超时限制，设置withExecutionTimeoutEnabled(false) // withCoreSize(10) for (int i = 0; i < Integer.MAX_VALUE; i++) { Thread thread = new ThreadRunner(i); thread.start(); Thread.sleep(500); } }}执行结果如下：
16:52:14.404 [hystrix-helloWorldThreadPool-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 0-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-116:52:14.463 [hystrix-helloWorldThreadPool-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 1-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-216:52:14.964 [hystrix-helloWorldThreadPool-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 2-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-316:52:15.464 [hystrix-helloWorldThreadPool-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 3-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-416:52:15.965 [hystrix-helloWorldThreadPool-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 4-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-516:52:16.466 [hystrix-helloWorldThreadPool-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 5-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-616:52:16.966 [hystrix-helloWorldThreadPool-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 6-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-716:52:17.466 [hystrix-helloWorldThreadPool-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 7-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-816:52:17.967 [hystrix-helloWorldThreadPool-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 8-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-916:52:18.466 [hystrix-helloWorldThreadPool-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 9-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-1016:52:18.970 [Thread-10] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:18.973 [Thread-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:19.466 [Thread-11] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:19.467 [Thread-11] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:19.967 [Thread-12] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:19.967 [Thread-12] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:20.468 [Thread-13] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:20.468 [Thread-13] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:20.968 [Thread-14] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:20.968 [Thread-14] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:21.469 [Thread-15] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:21.469 [Thread-15] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:21.970 [Thread-16] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:21.970 [Thread-16] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:22.469 [Thread-17] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:22.469 [Thread-17] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:22.970 [Thread-18] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:22.971 [Thread-18] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:23.471 [Thread-19] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:23.472 [Thread-19] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:23.972 [Thread-20] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:23.972 [Thread-20] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:24.405 [hystrix-helloWorldThreadPool-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 0-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-116:52:24.406 [Thread-0] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 0执行完毕16:52:24.464 [hystrix-helloWorldThreadPool-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 1-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-216:52:24.464 [Thread-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 1执行完毕16:52:24.472 [Thread-21] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:24.473 [Thread-21] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:24.964 [hystrix-helloWorldThreadPool-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 2-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-316:52:24.964 [Thread-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 2执行完毕16:52:24.973 [Thread-22] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:24.973 [Thread-22] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:25.465 [hystrix-helloWorldThreadPool-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 3-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-416:52:25.465 [Thread-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 3执行完毕16:52:25.473 [Thread-23] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:25.473 [Thread-23] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:25.966 [hystrix-helloWorldThreadPool-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 4-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-516:52:25.966 [Thread-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 4执行完毕16:52:25.975 [Thread-24] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:25.975 [Thread-24] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:26.466 [hystrix-helloWorldThreadPool-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 5-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-616:52:26.466 [Thread-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 5执行完毕16:52:26.475 [hystrix-helloWorldThreadPool-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 25-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-616:52:26.967 [hystrix-helloWorldThreadPool-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 6-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-716:52:26.973 [Thread-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 6执行完毕16:52:26.976 [hystrix-helloWorldThreadPool-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 26-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-716:52:27.466 [hystrix-helloWorldThreadPool-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 7-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-816:52:27.466 [Thread-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 7执行完毕16:52:27.476 [hystrix-helloWorldThreadPool-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 27-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-816:52:27.967 [hystrix-helloWorldThreadPool-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 8-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-916:52:27.967 [Thread-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 8执行完毕16:52:27.977 [hystrix-helloWorldThreadPool-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 28-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-916:52:28.467 [hystrix-helloWorldThreadPool-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 9-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-1016:52:28.467 [Thread-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 9执行完毕16:52:28.477 [hystrix-helloWorldThreadPool-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 29-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-1016:52:28.977 [hystrix-helloWorldThreadPool-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 30-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-516:52:29.478 [hystrix-helloWorldThreadPool-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 31-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-416:52:29.978 [hystrix-helloWorldThreadPool-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 32-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-316:52:30.479 [hystrix-helloWorldThreadPool-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 33-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-216:52:30.979 [hystrix-helloWorldThreadPool-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 34-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-116:52:31.479 [Thread-35] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:31.480 [Thread-35] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:31.980 [Thread-36] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:31.981 [Thread-36] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:32.481 [Thread-37] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:32.481 [Thread-37] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:32.981 [Thread-38] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:32.981 [Thread-38] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:33.482 [Thread-39] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:33.482 [Thread-39] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:33.982 [Thread-40] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:33.983 [Thread-40] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:34.482 [Thread-41] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:34.482 [Thread-41] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:34.983 [Thread-42] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:34.983 [Thread-42] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:35.483 [Thread-43] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:35.483 [Thread-43] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:35.984 [Thread-44] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:35.984 [Thread-44] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK16:52:36.475 [hystrix-helloWorldThreadPool-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 25-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-616:52:36.475 [Thread-25] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 25执行完毕16:52:36.484 [Thread-45] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 线程池/信号量已满 FALLBACK --> !16:52:36.484 [Thread-45] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - FALLBACK以上结果均符合预期
– END –
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