Hystrix实现Request Cache减压

本篇配置类及其他代码可参考《Hystrix使用fallback完成消费降级》

我们在Hystrix下新建一个CacheService

@Slf4j
@Service
public class RequestCacheService {@Autowiredprivate MyService service;@CacheResult@HystrixCommand(commandKey = "cacheKey")public Friend requestCache(@CacheKey String name) {log.info("request cache " + name);Friend friend = new Friend();friend.setName(name);friend = service.sayHiPost(friend);log.info("after requesting cache " + name);return friend;}
}

建立一个测试Controller，在这里我们尝试调用两次requestCache()

@GetMapping("/cache")
publicFriend cache(String name) {@Cleanup HystrixRequestContext context = HystrixRequestContext.initializeContext();Friend friend = requestCacheService.requestCache(name);friend = requestCacheService.requestCache(name);return friend;
}

启动项目，我们调用localhost:50000/cache?name=王老五
可以看到Feign的日志中，只触发了一次调用

我们对cache()函数稍微做一点修改

@GetMapping("/cache")
publicFriend cache(String name) {@Cleanup HystrixRequestContext context =  HystrixRequestContext.initializeContext();Friend friend = requestCacheService.requestCache(name);name += "!";friend = requestCacheService.requestCache(name);return friend;
}

重启项目，再次请求，这时候能看到Feign中触发了两次调用

说明@CacheKey已经生效了，在传入相同key时，触发了Hystrix的缓存!