在Spring中使用Netflix Hystrix批注

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我是靠谱客的博主单身裙子，这篇文章主要介绍在Spring中使用Netflix Hystrix批注，现在分享给大家，希望可以做个参考。

除了在主页上引述之外，我想不出更好的方式来描述Netflix Hystrix库的特定功能：

延迟和容错方式：
停止级联故障。后备和正常降级。无法快速快速恢复。使用断路器隔离线程和信号量。

我看到了Josh Long（ @starbuxman ）演示的示例，该示例使用了与Spring集成的Hystrix-具体代码在这里。该示例利用注释使hystrix启用服务类。

我的目标是在较小的单元测试模式下重新创建类似的设置。考虑到这一点，请考虑使用Hystrix库将使以下接口具有容错能力：

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package hystrixtest;
public interface RemoteCallService {
String call(String request) throws Exception;
}

还有一个虚拟的实现。虚拟实现委托给一个模拟实现，该模拟实现在前两次被调用时失败，并在第三次调用时成功：

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package hystrixtest;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.mockito.invocation.InvocationOnMock;
import org.mockito.stubbing.Answer;
import static org.mockito.Mockito.*;
public class DummyRemoteCallService implements RemoteCallService {
private RemoteCallService mockedDelegate;
public DummyRemoteCallService() {
try {
mockedDelegate = mock(RemoteCallService.class);
when(mockedDelegate.call(anyString()))
.thenThrow(new RuntimeException("Deliberately throwing an exception 1"))
.thenThrow(new RuntimeException("Deliberately throwing an exception 2"))
.thenAnswer(new Answer<String>() {
@Override
public String answer(InvocationOnMock invocationOnMock) throws Throwable {
return (String) invocationOnMock.getArguments()[0];
}
});
}catch(Exception e) {
throw new IllegalStateException(e);
}
}
@Override
@HystrixCommand(fallbackMethod = "fallBackCall")
public String call(String request) throws Exception {
return this.mockedDelegate.call(request);
}
public String fallBackCall(String request) {
return "FALLBACK: " + request;
}
}

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package hystrixtest;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.mockito.invocation.InvocationOnMock;
import org.mockito.stubbing.Answer;
import static org.mockito.Mockito.*;
public class DummyRemoteCallService implements RemoteCallService {
private RemoteCallService mockedDelegate;
public DummyRemoteCallService() {
try {
mockedDelegate = mock(RemoteCallService.class);
when(mockedDelegate.call(anyString()))
.thenThrow(new RuntimeException("Deliberately throwing an exception 1"))
.thenThrow(new RuntimeException("Deliberately throwing an exception 2"))
.thenAnswer(new Answer<String>() {
@Override
public String answer(InvocationOnMock invocationOnMock) throws Throwable {
return (String) invocationOnMock.getArguments()[0];
}
});
}catch(Exception e) {
throw new IllegalStateException(e);
}
}
@Override
@HystrixCommand(fallbackMethod = "fallBackCall")
public String call(String request) throws Exception {
return this.mockedDelegate.call(request);
}
public String fallBackCall(String request) {
return "FALLBACK: " + request;
}
}

远程调用已使用@Hystrixcommand批注进行了批注，并具有基本配置，以便在远程调用失败时退回到“ fallBackCall”方法。

现在，您可以想象，Hystrix库中必须有一些东西可以拦截用@HystrixCommand注释注释的调用，并使其具有容错能力。这是一个有效的测试，将必要的基础结构包装在一起–本质上，Hystrix库提供了一个基于AOP的配套库，可拦截调用。我在这里使用了Spring测试支持来引导AOP基础结构，将HystrixCommandAspect创建为bean，对于前两个失败的调用，该调用转到“ fallBackCall”，并在第三次成功进行：

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package hystrixtest;
import com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
public class TestRemoteCallServiceHystrix {
@Autowired
private RemoteCallService remoteCallService ;
@Test
public void testRemoteCall() throws Exception{
assertThat(this.remoteCallService.call("test"), is("FALLBACK: test"));
assertThat(this.remoteCallService.call("test"), is("FALLBACK: test"));
assertThat(this.remoteCallService.call("test"), is("test"));
}
@Configuration
@EnableAspectJAutoProxy
public static class SpringConfig {
@Bean
public HystrixCommandAspect hystrixCommandAspect() {
return new HystrixCommandAspect();
}
@Bean
public RemoteCallService remoteCallService() {
return new DummyRemoteCallService();
}
}
}

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package hystrixtest;
import com.netflix.hystrix.contrib.javanica.aop.aspectj.HystrixCommandAspect;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration
public class TestRemoteCallServiceHystrix {
@Autowired
private RemoteCallService remoteCallService ;
@Test
public void testRemoteCall() throws Exception{
assertThat(this.remoteCallService.call("test"), is("FALLBACK: test"));
assertThat(this.remoteCallService.call("test"), is("FALLBACK: test"));
assertThat(this.remoteCallService.call("test"), is("test"));
}
@Configuration
@EnableAspectJAutoProxy
public static class SpringConfig {
@Bean
public HystrixCommandAspect hystrixCommandAspect() {
return new HystrixCommandAspect();
}
@Bean
public RemoteCallService remoteCallService() {
return new DummyRemoteCallService();
}
}
}

Spring-Cloud为基于Spring-Boot的项目提供了一种配置Netflix库的简便方法，如果我要使用该库，则测试会转换为该库，现在借助Spring-Boot注释掉一堆配置：

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package hystrixtest;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration
public class TestRemoteCallServiceHystrix {
@Autowired
private RemoteCallService remoteCallService;
@Test
public void testRemoteCall() throws Exception {
assertThat(this.remoteCallService.call("test"), is("FALLBACK: test"));
assertThat(this.remoteCallService.call("test"), is("FALLBACK: test"));
assertThat(this.remoteCallService.call("test"), is("test"));
}
@Configuration
@EnableAutoConfiguration
//
@EnableAspectJAutoProxy
@EnableHystrix
public static class SpringConfig {
//
@Bean
//
public HystrixCommandAspect hystrixCommandAspect() {
//
return new HystrixCommandAspect();
//
}
@Bean
public RemoteCallService remoteCallService() {
return new DummyRemoteCallService();
}
}
}

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package hystrixtest;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.test.SpringApplicationConfiguration;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.hamcrest.Matchers.is;
@RunWith(SpringJUnit4ClassRunner.class)
@SpringApplicationConfiguration
public class TestRemoteCallServiceHystrix {
@Autowired
private RemoteCallService remoteCallService;
@Test
public void testRemoteCall() throws Exception {
assertThat(this.remoteCallService.call("test"), is("FALLBACK: test"));
assertThat(this.remoteCallService.call("test"), is("FALLBACK: test"));
assertThat(this.remoteCallService.call("test"), is("test"));
}
@Configuration
@EnableAutoConfiguration
//
@EnableAspectJAutoProxy
@EnableHystrix
public static class SpringConfig {
//
@Bean
//
public HystrixCommandAspect hystrixCommandAspect() {
//
return new HystrixCommandAspect();
//
}
@Bean
public RemoteCallService remoteCallService() {
return new DummyRemoteCallService();
}
}
}