Spring Cloud Hystrix 服务降级限流策略详解

@RestController
@RequestMapping("/hystrix")
@DefaultProperties(defaultFallback = "timeOutFallbackMethod")
public class HystrixController {
    @Autowired
    private IHystrixService iHystrixService;
    @GetMapping("/error")
    @HystrixCommand
    public String errorMethod() {
        int i = 10 / 0;
        return iHystrixService.fallBackMethodOk();
    }
    @GetMapping("/timeOut")
    @HystrixCommand(fallbackMethod = "timeOutFallbackMethod", commandProperties = {
            //超过2秒及服务降级
            @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "2000")
    })
    public String timeOutMethod() throws InterruptedException {
        //线程睡眠3秒
        return iHystrixService.timeOutMethod();
    }
    /**
     * 降级方法
     *
     * @return
     */
    private String timeOutFallbackMethod() {
        return "服务访问失败，降级处理";
    }
}

@RestController
@AllArgsConstructor
@RequestMapping("/provider")
public class HystrixProviderController {
    @Autowired
    private HystrixService hystrixService;
    /**
     * 模拟接口错误场景
     * @return
     */
    @GetMapping("/executeProviderMethod1")
    public String executeProviderMethod1(){
        int i =5/0;
        String result = hystrixService.errorMethod();
        return result;
    }
}

@FeignClient(contextId = "hystrixService", value = "Lxlxxx-system", fallbackFactory = HystrixFallbackFactory.class)
public interface HystrixService {
    /**
     * 异常方法
     *
     * @return
     */
    @GetMapping("/hystrix/error")
    public String errorMethod();
    /**
     * 超时方法
     *
     * @return
     */
    @GetMapping("/hystrix/timeOut")
    public String timeOutMethod();
}

@Component
@Slf4j
public class HystrixFallbackFactory implements FallbackFactory<HystrixService> {
    @Override
    public HystrixService create(Throwable cause) {
        log.error("用户服务调用失败:{}", cause.getMessage());
        return new HystrixService() {
            @Override
            public String errorMethod() {
                return "触发system 服务的降级方法";
            }
            @Override
            public String timeOutMethod() {
                return null;
            }
        };
    }
}

@Service
@Slf4j
public class HystrixServiceImpl implements IHystrixService {
    //服务熔断
    @HystrixCommand(fallbackMethod = "fallback",commandProperties = {
            @HystrixProperty(name = "circuitBreaker.enabled",value = "true"),  //是否开启断路器
            @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold",value = "5"),   //请求次数
            @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds",value = "10000"),  //时间范围
            @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage",value = "60"), //失败率达到多少后跳闸
    })
    @Override
    public String countError(Integer count){
        //模拟报错
        if (count > 0){
            throw new RuntimeException("*****count 必须大于0");
        }
        return Thread.currentThread().getName()+"\t"+"调用成功";
    }
    public String fallback(Integer count){
        return "count 必修大于0    count: " +count;
    }
}