十一. SpringCloud Alibaba (12)

若 blockHandler 和 fallback 都进行了配置，则被限流降级而抛出 BlockException 时只会进入 blockHandler 处理逻辑。若未配置 blockHandler、fallback 和 defaultFallback，则被限流降级时会将 BlockException 直接抛出。

从 1.4.0 版本开始，注解方式定义资源支持自动统计业务异常，无需手动调用 Tracer.trace(ex) 来记录业务异常。Sentinel 1.4.0 以前的版本需要自行调用 Tracer.trace(ex) 来记录业务异常。

5.9 服务熔断功能

sentinel整合Ribbon + openFeign + fallback

启动nacos和sentinel

新建服务提供者9004/9005

pom重要依赖

<!--SpringCloud ailibaba nacos --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency>

yml

server: port: 9004 spring: application: name: nacos-payment-provider cloud: nacos: discovery: server-addr: localhost:8848 # 配置Nacos地址 management: endpoints: web: exposure: include: '*'

业务类

@RestController public class PaymentController { @Value("${server.port}") private String serverPort; public static HashMap<Long, Payment> hashMap = new HashMap<>(); static { hashMap.put(1L, new Payment(1L, "28a8c1e3bc2742d8848569891fb42181")); hashMap.put(2L, new Payment(2L, "bba8c1e3bc2742d8848569891ac32182")); hashMap.put(3L, new Payment(3L, "6ua8c1e3bc2742d8848569891xt92183")); } @GetMapping(value = "/paymentSQL/{id}") public CommonResult<Payment> paymentSQL(@PathVariable("id") Long id) { Payment payment = hashMap.get(id); CommonResult<Payment> result = new CommonResult(200, "from mysql,serverPort: " + serverPort, payment); return result; } }

新建服务消费者84

pom重要依赖

<!--SpringCloud openfeign --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency> <!--SpringCloud ailibaba nacos --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId> </dependency> <!--SpringCloud ailibaba sentinel --> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId> </dependency>

yml

server: port: 84 spring: application: name: nacos-order-consumer cloud: nacos: discovery: server-addr: localhost:8848 sentinel: transport: #配置Sentinel dashboard地址 dashboard: localhost:8080 #默认8719端口，假如被占用会自动从8719开始依次+1扫描,直至找到未被占用的端口 port: 8719 #消费者将要去访问的微服务名称(注册成功进nacos的微服务提供者) service-url: nacos-user-service: # 激活Sentinel对Feign的支持 feign: sentinel: enabled: true