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使用Hystrix时，下面的情况会触发fallback：
- 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。
- run()/construct()运行超时：执行命令的方法超时，将会触发fallback。
- 熔断器开启：当熔断器处于开启的状态，将会触发fallback。
- 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。
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
@EnableHystrix
public 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-1
16:41:22.496 [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-1
16:41:22.504 [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-2
16:41:23.505 [hystrix-helloWorldExceptionGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 1-HelloWorldExceptionCommand B--> hystrix-helloWorldExceptionGroup-2
16:41:23.506 [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-3
16:41:24.508 [hystrix-helloWorldExceptionGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 2-HelloWorldExceptionCommand B--> hystrix-helloWorldExceptionGroup-3
16:41:24.508 [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-4
16:41:25.508 [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-4
16:41:25.509 [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-5
16:41:26.511 [hystrix-helloWorldExceptionGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldExceptionCommand - 1-HelloWorldExceptionCommand B--> hystrix-helloWorldExceptionGroup-5
16:41:26.511 [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-1
16:09:25.906 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 超时降级! C--> HystrixTimer-1
16:09:25.913 [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-1
16:09:26.914 [hystrix-helloWorldTimeoutGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-2
16:09:26.914 [hystrix-helloWorldTimeoutGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-2
16:09:26.914 [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-3
16:09:27.915 [hystrix-helloWorldTimeoutGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-3
16:09:27.915 [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-4
16:09:29.418 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 超时降级! C--> HystrixTimer-1
16:09:29.419 [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-4
16:09:30.421 [hystrix-helloWorldTimeoutGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-5
16:09:30.421 [hystrix-helloWorldTimeoutGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-5
16:09:30.421 [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-6
16:09:31.423 [hystrix-helloWorldTimeoutGroup-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-6
16:09:31.423 [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-7
16:09:32.926 [HystrixTimer-4] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 超时降级! C--> HystrixTimer-4
16:09:32.926 [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-7
16:09:33.927 [hystrix-helloWorldTimeoutGroup-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-8
16:09:33.927 [hystrix-helloWorldTimeoutGroup-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-8
16:09:33.928 [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-9
16:09:34.929 [hystrix-helloWorldTimeoutGroup-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-9
16:09:34.929 [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-10
16:09:36.431 [HystrixTimer-3] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 超时降级! C--> HystrixTimer-3
16:09:36.432 [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-10
16:09:37.433 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand A--> hystrix-helloWorldTimeoutGroup-10
16:09:37.433 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-10
16:09:37.433 [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-10
16:09:38.435 [hystrix-helloWorldTimeoutGroup-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldTimeoutCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldTimeoutGroup-10
16:09:38.435 [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-1
16:35:36.190 [hystrix-helloWorldBreakerGroup-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-1
16:35:36.193 [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-2
16:35:37.195 [hystrix-helloWorldBreakerGroup-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-2
16:35:37.201 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-1
16:35:37.202 [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-3
16:35:38.203 [hystrix-helloWorldBreakerGroup-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 2-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-3
16:35:38.203 [HystrixTimer-2] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-2
16:35:38.204 [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-4
16:35:39.205 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-1
16:35:39.205 [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-5
16:35:40.206 [hystrix-helloWorldBreakerGroup-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 4-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-5
16:35:40.206 [HystrixTimer-3] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-3
16:35:40.206 [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-6
16:35:41.207 [hystrix-helloWorldBreakerGroup-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 5-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-6
16:35:41.207 [HystrixTimer-2] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-2
16:35:41.208 [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-7
16:35:42.210 [hystrix-helloWorldBreakerGroup-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 6-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-7
16:35:42.211 [HystrixTimer-4] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-4
16:35:42.212 [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--> main
16:35:42.213 [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--> main
16:35:42.214 [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--> main
16:35:42.214 [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--> main
16:35:43.215 [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--> main
16:35:43.215 [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--> main
16:35:43.216 [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--> main
16:35:43.216 [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--> main
16:35:43.216 [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--> main
16:35:43.216 [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--> main
16:35:43.216 [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--> main
16:35:43.216 [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--> main
16:35:43.217 [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--> main
16:35:43.217 [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--> main
16:35:44.218 [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--> main
16:35:44.218 [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--> main
16:35:44.218 [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--> main
16:35:44.218 [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--> main
16:35:44.218 [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--> main
16:35:44.219 [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--> main
16:35:44.219 [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--> main
16:35:44.219 [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--> main
16:35:44.219 [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--> main
16:35:44.219 [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-8
16:35:45.220 [hystrix-helloWorldBreakerGroup-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 0-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-8
16:35:45.225 [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-9
16:35:46.227 [hystrix-helloWorldBreakerGroup-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 1-HelloWorldTimeoutCommand B--> hystrix-helloWorldBreakerGroup-9
16:35:46.227 [HystrixTimer-1] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-1
16:35:46.228 [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-10
16:35:47.229 [HystrixTimer-3] ERROR com.rambo.hystrixtest.degrade.command.HelloWorldBreakerCommand - 熔断降级! C--> HystrixTimer-3
16:35:47.230 [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-1
16:52:14.463 [hystrix-helloWorldThreadPool-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 1-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-2
16:52:14.964 [hystrix-helloWorldThreadPool-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 2-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-3
16:52:15.464 [hystrix-helloWorldThreadPool-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 3-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-4
16:52:15.965 [hystrix-helloWorldThreadPool-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 4-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-5
16:52:16.466 [hystrix-helloWorldThreadPool-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 5-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-6
16:52:16.966 [hystrix-helloWorldThreadPool-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 6-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-7
16:52:17.466 [hystrix-helloWorldThreadPool-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 7-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-8
16:52:17.967 [hystrix-helloWorldThreadPool-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 8-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-9
16:52:18.466 [hystrix-helloWorldThreadPool-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 9-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-10
16:52:18.970 [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 - FALLBACK
16:52:19.466 [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 - FALLBACK
16:52:19.967 [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 - FALLBACK
16:52:20.468 [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 - FALLBACK
16:52:20.968 [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 - FALLBACK
16:52:21.469 [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 - FALLBACK
16:52:21.970 [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 - FALLBACK
16:52:22.469 [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 - FALLBACK
16:52:22.970 [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 - FALLBACK
16:52:23.471 [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 - FALLBACK
16:52:23.972 [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 - FALLBACK
16:52:24.405 [hystrix-helloWorldThreadPool-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 0-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-1
16:52:24.406 [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-2
16:52:24.464 [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 - FALLBACK
16:52:24.964 [hystrix-helloWorldThreadPool-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 2-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-3
16:52:24.964 [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 - FALLBACK
16:52:25.465 [hystrix-helloWorldThreadPool-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 3-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-4
16:52:25.465 [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 - FALLBACK
16:52:25.966 [hystrix-helloWorldThreadPool-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 4-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-5
16:52:25.966 [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 - FALLBACK
16:52:26.466 [hystrix-helloWorldThreadPool-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 5-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-6
16:52:26.466 [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-6
16:52:26.967 [hystrix-helloWorldThreadPool-7] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 6-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-7
16:52:26.973 [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-7
16:52:27.466 [hystrix-helloWorldThreadPool-8] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 7-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-8
16:52:27.466 [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-8
16:52:27.967 [hystrix-helloWorldThreadPool-9] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 8-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-9
16:52:27.967 [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-9
16:52:28.467 [hystrix-helloWorldThreadPool-10] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 9-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-10
16:52:28.467 [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-10
16:52:28.977 [hystrix-helloWorldThreadPool-5] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 30-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-5
16:52:29.478 [hystrix-helloWorldThreadPool-4] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 31-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-4
16:52:29.978 [hystrix-helloWorldThreadPool-3] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 32-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-3
16:52:30.479 [hystrix-helloWorldThreadPool-2] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 33-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-2
16:52:30.979 [hystrix-helloWorldThreadPool-1] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 34-HelloWorldThreadPoolCommand A--> hystrix-helloWorldThreadPool-1
16:52:31.479 [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 - FALLBACK
16:52:31.980 [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 - FALLBACK
16:52:32.481 [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 - FALLBACK
16:52:32.981 [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 - FALLBACK
16:52:33.482 [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 - FALLBACK
16:52:33.982 [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 - FALLBACK
16:52:34.482 [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 - FALLBACK
16:52:34.983 [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 - FALLBACK
16:52:35.483 [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 - FALLBACK
16:52:35.984 [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 - FALLBACK
16:52:36.475 [hystrix-helloWorldThreadPool-6] INFO com.rambo.hystrixtest.degrade.command.HelloWorldThreadPoolCommand - 25-HelloWorldThreadPoolCommand B--> hystrix-helloWorldThreadPool-6
16:52:36.475 [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 –
|
