SpringCloud熔断机制-ribbon结合hystrix

妖狐艹你老母 2023-07-04 15:38 33阅读 0赞

# ribbon服务 #

## 1.pom依赖 ##

<dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
            </dependency>

## 2.配置 ##

创建CommandForIndex类

public class CommandForIndex extends HystrixCommand<Object> {
    
        private final RestTemplate template;
    
        private String id;
    
        public CommandForIndex(String id, RestTemplate restTemplate) {
            // java代码配置， 只针对这个命令
            super(Setter
                    // 必填项,用于统计,指定命令分组名
                    .withGroupKey(HystrixCommandGroupKey.Factory.asKey("Hello-Group"))
                    // 熔断配置依赖名称,默认值command实现类的类名(比如这个就是CommandForIndex),如果是服务调用,则写具体的接口名
                    .andCommandKey(HystrixCommandKey.Factory.asKey("ConsumerController"))
                    // 线程池配置依赖名称，默认值HystrixCommandGroupKey的名称
                    .andThreadPoolKey(HystrixThreadPoolKey.Factory.asKey("User-ThreadPool"))
                    // command 熔断相关参数配置
                    .andCommandPropertiesDefaults(HystrixCommandProperties.Setter()
                                    // 配置隔离方式：默认采用线程池隔离。(还有信号量隔离方式)
                                     .withExecutionIsolationStrategy(HystrixCommandProperties.ExecutionIsolationStrategy.SEMAPHORE)
                                    // 超时时间500毫秒
                                    .withExecutionTimeoutInMilliseconds(500)
                            // 信号量隔离的模式下，最大的请求数。和线程池大小的意义一样
                            // .withExecutionIsolationSemaphoreMaxConcurrentRequests(2)
                            // 熔断时间（熔断开启后，各5秒后进入半开启状态，试探是否恢复正常）
                            // .withCircuitBreakerSleepWindowInMilliseconds(5000)
                    )
                    // 设置线程池参数
                    .andThreadPoolPropertiesDefaults(HystrixThreadPoolProperties.Setter()
                            // 线程池大小
                            .withCoreSize(1)
                            //允许最大的缓冲区大小
    //                       .withMaxQueueSize(2)
                    ));
            // super(HystrixCommandGroupKey.Factory.asKey("User-command"),100);
            this.id = id;
            this.template = restTemplate;
        }
    
        @Override
        protected Object run() throws Exception {
            System.out.println("###command#######" + Thread.currentThread().toString());
            Object result =  template.getForObject("http://helloclient/user?id="+id+"",Object.class);
            System.out.println(
                    "###command结束#######" + Thread.currentThread().toString() + ">><>>>执行结果:" + result.toString());
            return result;
        }
    
        @Override
        protected Object getFallback() {
            System.out.println("###降级啦####" + Thread.currentThread().toString());
            return "出錯了，我降級了";
            //降级的处理：
            //1.返回一个固定的值
            //2.去查询缓存
            //3.调用一个备用接口
        }
    }

## 测试 ##

修改Controller层

@RestController
    public class ConsumerController {
    
        @Autowired
        RestTemplate restTemplate;
    
        @GetMapping("")
        public Object index(@RequestParam("id")String id){
            //localhost:8001和http://helloclient等同 ,在配置文件中有相关配置
            //return restTemplate.getForObject("http://localhost:8001/user?id="+id+"",Object.class);
            //return restTemplate.getForObject("http://helloclient/user?id="+id+"",Object.class);
            return new CommandForIndex(id,restTemplate).execute();
        }
    
        @GetMapping("/get-teacher")
        public Object getTeacher(){
            //return restTemplate.getForEntity("http://localhost:8001",Teacher.class);
            return restTemplate.getForEntity("http://helloclient",Teacher.class);
        }
    
        public Object callTimeoutFallback(){
            return "查询超时啦，我降级了。";
        }
    }

修改hello-demo和ribbon服务的application.yml,将服务注册到注册中心上去

server:
      port: 8092
    
    ###定义实例名
    spring:
      application:
        name: spring-cloud-ribbon-consumer
    
    eureka:
      client:
        service-url:
          defaultZone: http://127.0.0.1:10000/eureka/

修改hello-demo服务的controller层,将第一个hello-demo请求接口sleep一秒钟

@GetMapping("user")
        public Object getUser(@Param("id")String id) throws InterruptedException {
            System.out.println("客户端1返回了请求");
            Thread.sleep(1000L);
            return helloService.get(id);
        }

启动服务  
服务请求超时,服务降级  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyODE1MTIy_size_16_color_FFFFFF_t_70]  
再次请求  
请求成功  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyODE1MTIy_size_16_color_FFFFFF_t_70 1]  
示例代码:  
[码云][Link 1]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyODE1MTIy_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/2020021213083780.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyODE1MTIy,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyODE1MTIy_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200212130917192.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQyODE1MTIy,size_16,color_FFFFFF,t_70
[Link 1]: https://gitee.com/mcwit/mcw_frame/tree/master/item/springcloud/day04_ribbon+hysrtix