Sentinel降级操作

1.通过对feign调用的降级 如果访问失败，则返回另外的信息

正常的feign调用

@FeignClient(value = "gulimall-seckill",fallback = SeckillFeignServiceFallback.class)
public interface SeckillFeignService {

    /**
     * 写给商品服务的接口，查询秒杀服务信息
     * @param skuId
     * @return
     */
    @GetMapping("/currentSeckillSkus/sku/seckill/{skuId}")
    R getSkuSeckillInfo(@PathVariable("skuId") Long skuId);
}

兜底方法返回另外的信息

/**
 * 如果feign调用失败返回的信息
 */
@Component
public class SeckillFeignServiceFallback implements SeckillFeignService {
    @Override
    public R getSkuSeckillInfo(Long skuId) {
        return R.error(500,方法调用失败);
    }
}

2.对代码进行访问控制，在可视化工具中对seckillSkus进行数据设置

@Override
    public List<SecKillSkuRedisTo> getCurrentSeckillSkus() {
        //1.确定当前时间属于哪个秒杀场次
        long time = new Date().getTime();
        try(Entry seckillSkus = SphU.entry("seckillSkus")){
            //正常的业务代码-----
            }
            //然后在可视化工具中对这个代码进行限流控制设置
        }catch (BlockException e){
            System.out.println("资源被限流");
        }
        return null;
    }

3.统一config配置返回降级信息

**
 * 自定义流量控制请求失败后返回信息
 */
@Configuration
public class SeckillSentinelConfig {

    public SeckillSentinelConfig(){
        WebCallbackManager.setUrlBlockHandler(new UrlBlockHandler() {
            @Override
            public void blocked(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockException e) throws IOException {
                R error = R.error(BizCodeEnum.TO_MANY_REQUEST.getCode(), BizCodeEnum.TO_MANY_REQUEST.getMsg());
                httpServletResponse.setCharacterEncoding("UTF-8");
                httpServletResponse.setContentType("application/json");
                httpServletResponse.getWriter().write(JSON.toJSONString(error));
            }
        });
    }
}

4.使用注解结合可视化操作进行控制

 public List<SecKillSkuRedisTo> blockHandler(BlockException e){
        log.error("getCurrentSeckillSkus被限流了");
        return null;
    }

    /**
     * 返回当前时间段可以参加秒杀的商品信息
     * Entry seckillSkus = SphU.entry("seckillSkus"对代码进行降级
     * @return
     */
    @SentinelResource(value = "getCurrentSeckillSkus",blockHandler = "blockHandler")
    @Override
    public List<SecKillSkuRedisTo> getCurrentSeckillSkus() {
       
       
        return null;
    }

 @SentinelResource(value = "getCurrentSeckillSkus",blockHandler = "blockHandler")

value的名称是可视化页面的限流处理名称

blockHandler的内容是限流降级后的操作方法

两个方法返回类型要一致

5.整合sentine和gateway

引入依赖

<!--        sentinel和gateway整合-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-sentinel-gateway</artifactId>
            <version>2.1.0.RELEASE</version>
        </dependency>

版本需要和common中的阿里依赖一致

<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.1.0.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

config文件

@Configuration
public class SentinelGatewayConfig {
    public SentinelGatewayConfig(){
        GatewayCallbackManager.setBlockHandler(new BlockRequestHandler() {
            @Override
            public Mono<ServerResponse> handleRequest(ServerWebExchange serverWebExchange, Throwable throwable) {
                R error = R.error(BizCodeEnum.TO_MANY_REQUEST.getCode(), BizCodeEnum.TO_MANY_REQUEST.getMsg());
                String jsonString = JSON.toJSONString(error);
                Mono<ServerResponse> body = ServerResponse.ok().body(Mono.just(jsonString), String.class);
                return body;
            }
        });
    }
}

也可以配置相关的信息

配置网关返回的状态码
spring.cloud.sentinel.scg.fallback.response-status=400