fix throw npe when router context is null (#634)

Co-authored-by: Haotian Zhang <928016560@qq.com>

CHANGELOG.md

@@ -6,3 +6,4 @@
 - [Optimize: Maybe remove Chinese characters](https://github.com/Tencent/spring-cloud-tencent/pull/608)
 - [Bugfix: fix feign report call result error when using feign direct call](https://github.com/Tencent/spring-cloud-tencent/pull/622)
 - [Feature: support spring-retry router](https://github.com/Tencent/spring-cloud-tencent/pull/633)
+- [Bugfix: fix throw npe when router context is null](https://github.com/Tencent/spring-cloud-tencent/pull/634)

spring-cloud-starter-tencent-polaris-router/src/main/java/com/tencent/cloud/polaris/router/PolarisRouterServiceInstanceListSupplier.java

@@ -59,11 +59,11 @@ import static com.tencent.cloud.common.constant.ContextConstant.UTF_8;
 
 /**
  * Service routing entrance.
- *
+ * <p>
  * Rule routing needs to rely on request parameters for server filtering.
  * The interface cannot obtain the context object of the request granularity,
  * so the routing capability cannot be achieved through ServerListFilter.
- *
+ * <p>
  * And {@link PolarisRouterServiceInstanceListSupplier#get(Request)} provides the ability to pass in http headers,
  * so routing capabilities are implemented through IRule.
  *
@@ -95,21 +95,23 @@ public class PolarisRouterServiceInstanceListSupplier extends DelegatingServiceI
 		Flux<List<ServiceInstance>> allServers = getDelegate().get();
 
 		// 2. filter by router
+		PolarisRouterContext routerContext = null;
+
 		DefaultRequestContext requestContext = (DefaultRequestContext) request.getContext();
-		PolarisRouterContext key;
 		if (requestContext instanceof RequestDataContext) {
-			key = buildRouterContext(((RequestDataContext) requestContext).getClientRequest().getHeaders());
+			routerContext = buildRouterContext(((RequestDataContext) requestContext).getClientRequest().getHeaders());
 		}
 		else if (requestContext.getClientRequest() instanceof PolarisLoadBalancerRequest) {
-			key = buildRouterContext(((PolarisLoadBalancerRequest<?>) requestContext.getClientRequest()).getRequest()
+			routerContext = buildRouterContext(((PolarisLoadBalancerRequest<?>) requestContext.getClientRequest()).getRequest()
 					.getHeaders());
 		}
-		else {
+
+		if (routerContext == null) {
 			// return all servers if router context is null.
 			return allServers;
 		}
 
-		return doRouter(allServers, key);
+		return doRouter(allServers, routerContext);
 	}
 
 	//set method to public for unit test