spring cloud 2021.x 源码阅读, OpenFeign + LoadBalancer + Nacos Discovery

pom.xml

@@ -71,10 +71,10 @@
 					<target>1.8</target>
 				</configuration>
 			</plugin>
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-checkstyle-plugin</artifactId>
-			</plugin>
+<!--			<plugin>-->
+<!--				<groupId>org.apache.maven.plugins</groupId>-->
+<!--				<artifactId>maven-checkstyle-plugin</artifactId>-->
+<!--			</plugin>-->
 			<plugin>
 				<groupId>io.spring.javaformat</groupId>
 				<artifactId>spring-javaformat-maven-plugin</artifactId>
@@ -91,14 +91,14 @@
 		</plugins>
 	</build>
 
-	<reporting>
-		<plugins>
-			<plugin>
-				<groupId>org.apache.maven.plugins</groupId>
-				<artifactId>maven-checkstyle-plugin</artifactId>
-			</plugin>
-		</plugins>
-	</reporting>
+<!--	<reporting>-->
+<!--		<plugins>-->
+<!--			<plugin>-->
+<!--				<groupId>org.apache.maven.plugins</groupId>-->
+<!--				<artifactId>maven-checkstyle-plugin</artifactId>-->
+<!--			</plugin>-->
+<!--		</plugins>-->
+<!--	</reporting>-->
 
 	<dependencyManagement>
 		<dependencies>

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/loadbalancer/FeignBlockingLoadBalancerClient.java

@@ -15,7 +15,7 @@
  */
 
 package org.springframework.cloud.openfeign.loadbalancer;
-
+// comment-by-kai 源码阅读 spring cloud 2021.x
 import java.io.IOException;
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
@@ -94,6 +94,8 @@ public class FeignBlockingLoadBalancerClient implements Client {
 						loadBalancerClientFactory.getInstances(serviceId, LoadBalancerLifecycle.class),
 						RequestDataContext.class, ResponseData.class, ServiceInstance.class);
 		supportedLifecycleProcessors.forEach(lifecycle -> lifecycle.onStart(lbRequest));
+
+		// loadBalancerClient根据serviceId，选择合适的ServiceInstance
 		ServiceInstance instance = loadBalancerClient.choose(serviceId, lbRequest);
 		org.springframework.cloud.client.loadbalancer.Response<ServiceInstance> lbResponse = new DefaultResponse(
 				instance);
@@ -108,6 +110,8 @@ public class FeignBlockingLoadBalancerClient implements Client {
 			return Response.builder().request(request).status(HttpStatus.SERVICE_UNAVAILABLE.value())
 					.body(message, StandardCharsets.UTF_8).build();
 		}
+
+		// 重构URL，替换serviceId为实际的通信地址
 		String reconstructedUrl = loadBalancerClient.reconstructURI(instance, originalUri).toString();
 		Request newRequest = buildRequest(request, reconstructedUrl);
 		LoadBalancerProperties loadBalancerProperties = loadBalancerClientFactory.getProperties(serviceId);