Spring Cloud Hystrix

Spring Cloud Hystrix

创建spring-cloud-03-hystrix-server服务中心 端口为8088

创建spring-cloud-03-hystrix-client服务单元

• HelloControl类

@RestControllerpublic class HelloControl {    @RequestMapping(value = "/hello",method = {RequestMethod.GET})    public String hello() throws InterruptedException {        Thread.sleep(3000);        System.err.println("hello hystrix ....");        return "hello hystrix ...";    }    @RequestMapping(value = "/action",method = {RequestMethod.GET})    public String action() throws InterruptedException {        Thread.sleep(5000);        System.err.println("action hystrix ....");        return "action hystrix ...";    }}

创建spring-cloud-03-hystrix-request-a 消费端

• pom.xml引入jar

<dependency>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-web</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-ribbon</artifactId></dependency><dependency>    <groupId>org.springframework.cloud</groupId>    <artifactId>spring-cloud-starter-hystrix</artifactId></dependency><dependency>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-actuator</artifactId></dependency>

• application.properties

spring.application.name=hystrix-requestserver.context-path=/server.port=2003eureka.client.service-url.defaultZone=http://eureka1:8008/eureka/#启动重试机制spring.cloud.loadbalancer.retry.enabled=true ##断路器超时时间hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds=2000req.fact.connect-timeout=1000req.fact.connection-request-timeout=1000req.fact.read-timeout=30000#是否对所有请求都进行重试client-service.ribbon.OKToRetryOnAllOperations=true#重试切换实例得次数client-service.ribbon.MaxAutoRetriesNextServer=1#重试切次数client-service.ribbon.MaxAutoRetries=5

• Application类

@EnableCircuitBreaker //开启断路器@EnableDiscoveryClient@SpringBootApplicationpublic class HystrixRequestAApplication {    @Bean    @ConfigurationProperties(prefix = "req.fact")    public HttpComponentsClientHttpRequestFactory httpComponentsClientHttpRequestFactory(){        return new HttpComponentsClientHttpRequestFactory();    }    @Bean    @LoadBalanced    public RestTemplate restTemplate(){        return new RestTemplate(httpComponentsClientHttpRequestFactory());    }    public static void main(String[] args) {        SpringApplication.run(HystrixRequestAApplication.class, args);    }}

• HystrixC类

@RestControllerpublic class HystrixC {    @Autowired    private HelloService helloService;    @RequestMapping(value = "/hello",method = {RequestMethod.GET})    public String hello(){        return helloService.hello();    }    @RequestMapping(value = "/hystrix-handler",method = {RequestMethod.GET})    public String handler(){        return helloService.handler();    }    @RequestMapping(value = "/hystrix-action",method = {RequestMethod.GET})    public String action(){        return helloService.action();    }}

• HelloService类

@Servicepublic class HelloService {    @Autowired    RestTemplate restTemplate;    @HystrixCommand(fallbackMethod = "helloFailback")    public String hello() {      return  restTemplate.getForObject("http://client-service/hello",String.class);    }    public String helloFailback(){        System.out.println("----执行降级策略----");        return "----执行降级策略----";    }    @HystrixCommand(fallbackMethod = "handlerFailback", ignoreExceptions = {BadRequestException.class})    public String handler() {        throw new RuntimeException("运行时异常");    }    public String handlerFailback(Throwable e){        System.err.println("异常信息:"+ e.getMessage());        return "获取异常信息并可以做具体的降级处理";    }    @HystrixCommand(            commandKey = "actionKey",            commandProperties = {@HystrixProperty(name="execution.isolation.thread.timeoutInMilliseconds", /*KEY*/ value = "8000" /*VALUE*/)},            fallbackMethod = "actionFailback")    public String action() {       return restTemplate.getForObject("http://client-service/action",String.class);    }    public String actionFailback(){        System.out.println("----执行降级策略----");        return "----执行降级策略----";    }}

• 全部启动 http://localhost:2003/hello访问时，将产生降级策略，因为设置的熔断器得时间为2ms，在client端睡眠了3ms，就会产生降级策略，当访问 http://localhost:2003/hystrix-action时，不会产生降级策略，因为Hystrix熔断器可以指定在特定方法中。

Hystrix Dashboard仪表盘

• 仪表盘就是为了监控得，方便服务接口进行测试排查,架构如下：
  

创建spring-cloud-03-hystrix-dashboard 项目

• 引入响应得jar包，spring-cloud-starter-hystrix-dashboard，并且要监控得服务必须依赖spring-boot-starter-actuator jar包
• Application类

@EnableHystrixDashboard //启动断路器监控@EnableDiscoveryClient@SpringBootApplicationpublic class HystrixDashboardApplication {    // 监控台地址: http://localhost:8011/hystrix    // 查看[我们要监控哪一个断路器服务]什么样的数据,写上具体的地址: http://localhost:2003/hystrix.stream    public static void main(String[] args) {        SpringApplication.run(HystrixDashboardApplication.class, args);    }}

• 启用仪表盘注解配置：@EnableHystrixDashboard通过访问http://localhost:8011/hystrix可看到流量监控台，在下面输入要监控得服务地址即可。

Hystrix Turbine 集群监控

• 对于集群得情况，dashbroad是不行得，需要引用一个收集组件Turbine进行汇总数据，最后流入到我们得监控台（dashboard）中去，引入spring-cloud-starter-turbine依赖，并添加注解@EnableTurbine,对application.properties中turbine进行配置

spring.application.name=hystrix-turbineserver.port=3000server.context-path=/management.port=3001#指定要收集集群控制信息得服务名turbine.app-config=hystrix-request turbine.cluster-name-expression="default"turbine.combine-host-port=trueeureka.client.service-url.defaultZone=http://eureka1:8008/eureka/

• Application类

@EnableTurbine          //启用收集断路器集群服务功能@EnableDiscoveryClient@SpringBootApplicationpublic class HystrixTurbineApplication {    // 要监控的turbine地址[监控hystrix-request服务]: http://localhost:3000/turbine.stream    // turbine是集群监控 dashboard中输入得是turbine得地址 turbine是集群得集合    public static void main(String[] args) {        SpringApplication.run(HystrixTurbineApplication.class, args);    }}

• Turbine与dashboard整合架构如下：

• 复制spring-cloud-03-hystrix-request-a项目为b，启动spring-cloud-03-hystrix-request-b项目，启动Turbine，在dashboard中输入http://localhost:3000/turbine.stream，当a,b同时访问时，下面会出现
  

• GitHub地址

• 下节声明式服务调用组件Fegin