Spring Cloud - 断路器+（普通调用和feign封装调用）

(三) Spring Cloud - 断路器+（普通调用和feign封装调用）

1. Ribbon+Hystrix(断路器), 普通调用方式

pom.xml加入两个Hystrix依赖maven

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.sample</groupId>
<artifactId>2017-Netflix_Ribbon</artifactId>
<version>1.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>

<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
</parent>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency>
<dependency>
<groupId>com.netflix.hystrix</groupId>
<artifactId>hystrix-javanica</artifactId>
</dependency>
</dependencies>
</project>

Ribbon启动的boot application，修改如下

package com.jack.ssm;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
/**
* ClassName:RibbonApplication.java
* Date: 2017年5月13日下午5:06:00
* @author Jack.Huang
* @version V1.0
* @since JDK 1.7.0_60/JDK 1.8.0_45
*/
@SpringBootApplication
@EnableDiscoveryClient
@EnableCircuitBreaker // 注解开启断路器功能
public class RibbonApplication {
@Bean
@LoadBalanced
RestTemplate restTemplate() {
return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(RibbonApplication.class, args);
}
}

package com.jack.ssm.controller;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import com.jack.ssm.service.ComputeService;
/**
* ClassName:ConsumerController.java
* Date: 2017年5月13日下午5:10:00
* @author Jack.Huang
* @version V1.0
* @since JDK 1.7.0_60/JDK 1.8.0_45
*/
@RestController
public class ConsumerController {
/*
* 没有使用断路器之前的代码
*
@Autowired
RestTemplate restTemplate;
@RequestMapping(value = "/ribbonCallAddService", method = RequestMethod.GET)
public String add() {
// return restTemplate.getForEntity("http://COMPUTE-SERVICE/add?a=10&b=20", String.class).getBody();
return restTemplate.getForEntity("http://NETFLIX-SERVICE/add?a=10&b=20", String.class).getBody();
}
*/
/*
* 使用断路器之后的代码
*/
@Autowired
private ComputeService computeService;
@RequestMapping(value = "/ribbonCallAddService", method = RequestMethod.GET)
public String add() {
return computeService.addService();
}
}

package com.jack.ssm.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
/**
* ClassName:ComputeService.java
* Date: 2017年5月15日下午5:18:45
* @author Jack.Huang
* @version V1.0
* @since JDK 1.7.0_60/JDK 1.8.0_45
*/
@Service
public class ComputeService {
@Autowired
RestTemplate restTemplate;
@HystrixCommand(fallbackMethod = "addServiceFallback")
public String addService() {
return restTemplate.getForEntity("http://NETFLIX-SERVICE/add?a=10&b=20", String.class).getBody();
}
public String addServiceFallback() {
return "Error sevice";
}
}

调用链接：http://localhost:8000/ribbonCallAddService

2. Feign+Hystrix(断路器)调用方式

pom.xml, feign的依赖已经引入了hystrix，无需再引入也可以实现断路器

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.sample</groupId>
<artifactId>2017-Netflix_Feign</artifactId>
<version>1.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.3</version>
<configuration>

<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
</plugins>
</build>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
</parent>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>

<version>Dalston.RELEASE</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
<!-- <dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-hystrix</artifactId>
</dependency> -->
</dependencies>
</project>

application.yml, Dalston.RELEASE版本默认关闭hystrix, 其它版本则是默认打开

https://github.com/spring-cloud/spring-cloud-netflix/issues/1277这是spring社区关于为什么默认关闭的解析

server:
port: 8001
spring:
application:
name: feign-consumer
eureka:
service-url:
defaultZone: http://localhost:8761/eureka/
feign:
hystrix:
enabled: true

package com.jack.ssm.service;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import com.jack.ssm.service.hystrix.ComputeServiceHystrix;
/**
* ClassName:ComputeService.java
* Date: 2017年5月13日下午10:06:07
* @author Jack.Huang
* @version V1.0
* @since JDK 1.7.0_60/JDK 1.8.0_45
*/
@FeignClient(name = "NETFLIX-SERVICE", fallback = ComputeServiceHystrix.class)
public interface ComputeService {
@RequestMapping(method = RequestMethod.GET, value = "/add")
String add(@RequestParam(value = "a") Integer a, @RequestParam(value = "b") Integer b);
}

package com.jack.ssm.service.hystrix;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestParam;
import com.jack.ssm.service.ComputeService;
/**
* ClassName:ComputeClientHystrix.java
* Date: 2017年5月15日下午4:14:54
* @author Jack.Huang
* @version V1.0
* @since JDK 1.7.0_60/JDK 1.8.0_45
*/
@Component
public class ComputeServiceHystrix implements ComputeService {
@Override
public String add(@RequestParam(value = "a") Integer a, @RequestParam(value = "b") Integer b) {
return "Error service or service both down!";
}
}

调用链接http://localhost:8001/feignCallAddService

3.至于feign哪里默认关闭hystrix的源码如下

/*
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.cloud.netflix.hystrix.security;
import javax.annotation.PostConstruct;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.AllNestedConditions;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.cloud.netflix.hystrix.security.HystrixSecurityAutoConfiguration.HystrixSecurityCondition;
import org.springframework.context.annotation.Conditional;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.core.context.SecurityContext;
import com.netflix.hystrix.Hystrix;
import com.netflix.hystrix.strategy.HystrixPlugins;
import com.netflix.hystrix.strategy.concurrency.HystrixConcurrencyStrategy;
import com.netflix.hystrix.strategy.eventnotifier.HystrixEventNotifier;
import com.netflix.hystrix.strategy.executionhook.HystrixCommandExecutionHook;
import com.netflix.hystrix.strategy.metrics.HystrixMetricsPublisher;
import com.netflix.hystrix.strategy.properties.HystrixPropertiesStrategy;
/**
* @author Daniel Lavoie
*/
@Configuration
@Conditional(HystrixSecurityCondition.class)
@ConditionalOnClass({ Hystrix.class, SecurityContext.class })
public class HystrixSecurityAutoConfiguration {
@Autowired(required = false)
private HystrixConcurrencyStrategy existingConcurrencyStrategy;
@PostConstruct
public void init() {
// Keeps references of existing Hystrix plugins.
HystrixEventNotifier eventNotifier = HystrixPlugins.getInstance()
.getEventNotifier();
HystrixMetricsPublisher metricsPublisher = HystrixPlugins.getInstance()
.getMetricsPublisher();
HystrixPropertiesStrategy propertiesStrategy = HystrixPlugins.getInstance()
.getPropertiesStrategy();
HystrixCommandExecutionHook commandExecutionHook = HystrixPlugins.getInstance()
.getCommandExecutionHook();
HystrixPlugins.reset();
// Registers existing plugins excepts the Concurrent Strategy plugin.
HystrixPlugins.getInstance().registerConcurrencyStrategy(
new SecurityContextConcurrencyStrategy(existingConcurrencyStrategy));
HystrixPlugins.getInstance().registerEventNotifier(eventNotifier);
HystrixPlugins.getInstance().registerMetricsPublisher(metricsPublisher);
HystrixPlugins.getInstance().registerPropertiesStrategy(propertiesStrategy);
HystrixPlugins.getInstance().registerCommandExecutionHook(commandExecutionHook);
}
static class HystrixSecurityCondition extends AllNestedConditions {
public HystrixSecurityCondition() {
super(ConfigurationPhase.REGISTER_BEAN);
}
@ConditionalOnProperty(name = "feign.hystrix.enabled", matchIfMissing = false)
static class HystrixEnabled {
}
@ConditionalOnProperty(name = "hystrix.shareSecurityContext")
static class ShareSecurityContext {
}
}
}

/*
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.cloud.netflix.feign;
import java.util.ArrayList;
import java.util.List;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
import org.springframework.cloud.netflix.feign.support.ResponseEntityDecoder;
import org.springframework.cloud.netflix.feign.support.SpringDecoder;
import org.springframework.cloud.netflix.feign.support.SpringEncoder;
import org.springframework.cloud.netflix.feign.support.SpringMvcContract;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Scope;
import org.springframework.core.convert.ConversionService;
import org.springframework.format.support.DefaultFormattingConversionService;
import org.springframework.format.support.FormattingConversionService;
import com.netflix.hystrix.HystrixCommand;
import feign.Contract;
import feign.Feign;
import feign.Logger;
import feign.Retryer;
import feign.codec.Decoder;
import feign.codec.Encoder;
import feign.hystrix.HystrixFeign;
/**
* @author Dave Syer
* @author Venil Noronha
*/
@Configuration
public class FeignClientsConfiguration {
@Autowired
private ObjectFactory<HttpMessageConverters> messageConverters;
@Autowired(required = false)
private List<AnnotatedParameterProcessor> parameterProcessors = new ArrayList<>();
@Autowired(required = false)
private List<FeignFormatterRegistrar> feignFormatterRegistrars = new ArrayList<>();
@Autowired(required = false)
private Logger logger;
@Bean
@ConditionalOnMissingBean
public Decoder feignDecoder() {
return new ResponseEntityDecoder(new SpringDecoder(this.messageConverters));
}
@Bean
@ConditionalOnMissingBean
public Encoder feignEncoder() {
return new SpringEncoder(this.messageConverters);
}
@Bean
@ConditionalOnMissingBean
public Contract feignContract(ConversionService feignConversionService) {
return new SpringMvcContract(this.parameterProcessors, feignConversionService);
}
@Bean
public FormattingConversionService feignConversionService() {
FormattingConversionService conversionService = new DefaultFormattingConversionService();
for (FeignFormatterRegistrar feignFormatterRegistrar : feignFormatterRegistrars) {
feignFormatterRegistrar.registerFormatters(conversionService);
}
return conversionService;
}
@Configuration
@ConditionalOnClass({ HystrixCommand.class, HystrixFeign.class })
protected static class HystrixFeignConfiguration {
@Bean
@Scope("prototype")
@ConditionalOnMissingBean
@ConditionalOnProperty(name = "feign.hystrix.enabled", matchIfMissing = false)
public Feign.Builder feignHystrixBuilder() {
return HystrixFeign.builder();
}
}
@Bean
@ConditionalOnMissingBean
public Retryer feignRetryer() {
return Retryer.NEVER_RETRY;
}
@Bean
@Scope("prototype")
@ConditionalOnMissingBean
public Feign.Builder feignBuilder(Retryer retryer) {
return Feign.builder().retryer(retryer);
}
@Bean
@ConditionalOnMissingBean(FeignLoggerFactory.class)
public FeignLoggerFactory feignLoggerFactory() {
return new DefaultFeignLoggerFactory(logger);
}
}

这两个地方都默认关闭了hystrix，@ConditionalOnProperty(name = "feign.hystrix.enabled", matchIfMissing = false)，实际两个都一起工作，这个有待后续研究 Spring Cloud - 断路器+（普通调用和feign封装调用）

本文依然是参考http://blog.didispace.com/springcloud3/，再加上自己翻阅官网源码。