Spring Cloud Gateway集成Nacos实现负载均衡

💡Nacas可以用于实现Spring Cloud Gateway中网关动态路由功能，也可以基于Nacos来实现对后端服务的负载均衡，前者利用Nacos配置中心功能，后者利用Nacos服务注册功能。

接下来我们来看下Gateway集成Nacos实现负载均衡的架构图

一. 环境准备

1. 版本环境

• Jdk: <java.version>1.8</java.version>

• SpringBoot: <version>2.4.2</version>

• SpringCloud: <spring.cloud.version>2020.0.1</spring.cloud.version>

• SpringCloudAlibaba: <spring-cloud-alibaba.version>2021.1</spring-cloud-alibaba.version>

2. 服务环境

• spring-cloud-user-center : 独立用户服务（2个）

• spring-cloud-gateway： 独立的网关服务

二. 实战

1. 创建用户服务

为了演示请求负载，将spring-cloud-user-center部署两份分别开放8005和8006端口

1. 引入相关依赖

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

2. yml配置

server:port: 8085spring:application:name: spring-cloud-user-centercloud:nacos:discovery:server-addr: 127.0.0.1:8848ip: 127.0.0.1
management:endpoints:web:exposure:include: "*"

3. 编写测试类

测试类1

/*** @author gf* @date 2023/2/14*/
@Slf4j
@RestController
public class UserController {@RequestMapping("/user")public String user(){log.info("hello Mr gateway,this is user server");return "hello Mr gateway,this is user server";}
}

重复以上1，2步骤重新创建一个服务，记得将配置文件中的端口号区分一下，然后

spring.application.name不变，依旧是spring-cloud-user-center。

测试类2

我们这里为了演示方便只是将之前的订单服务改造了一下，可以参考以下链接

SpringBoot整合Gateway+Nacos

@Slf4j
@RestController
public class OrderController {@RequestMapping("/user")public String getOrder(){log.info("hello Mr gateway,this is order server");return "hello Mr gateway,this is order server";}
}

4. 启动类

由于我们要将服务注册倒注册中心，所以我们在以内nacos依赖后要在启动类上添加@EnableDiscoveryClient注解

@EnableDiscoveryClient
@SpringBootApplication
public class SpringCloudUserCenterApplication {public static void main(String[] args) {SpringApplication.run(SpringCloudUserCenterApplication.class, args);}}

2.创建网关服务

1. 引入相关依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.4.2</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.scg</groupId><artifactId>spring-cloud-nacos</artifactId><version>0.0.1-SNAPSHOT</version><name>spring-cloud-gateway</name><description>Demo project for Spring Boot</description><properties><java.version>1.8</java.version><spring.cloud.version>2020.0.1</spring.cloud.version><spring-cloud-alibaba.version>2021.1</spring-cloud-alibaba.version></properties><dependencyManagement><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-dependencies</artifactId><version>${spring.cloud.version}</version><type>pom</type><scope>import</scope></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-alibaba-dependencies</artifactId><version>${spring-cloud-alibaba.version}</version><type>pom</type><scope>import</scope></dependency></dependencies></dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-gateway</artifactId></dependency><!--得不加上这个配置，不然会报503--><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-loadbalancer</artifactId></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build>
</project>

2. 配置yml文件

server:port: 8082
spring:application:name: gateway_servercloud:nacos:discovery:server-addr: 127.0.0.1:8848gateway:discovery:locator:#开启从注册中心动态创建路由的功能，利用微服务名进行路由enabled: true#开启小写验证，默认feign根据服务名查找都是用的全大写lowerCaseServiceId: trueroutes:- id: spring-cloud-user-centeruri: lb://spring-cloud-user-center# 断言,路径相匹配的进行路由predicates:- Path=/user-center/**filters:- StripPrefix=1
management:endpoints:web:exposure:include: "*"

3. 测试

nacos可视化界面请参考：SpringCloud Alibaba 之 Nacos注册中心实战

同时启动三台服务，我们可以看到这三者服役已经注册到了nacos注册中心中

按照我们的配置，访问http://localhost:8082/user-center/user，查看接口访问情况

可以看到，调用了两次，两次请求的服务不同