Nacos服务调用(基于Openfeign)

在<<Nacos服务注册>>这篇文章里，我搭建了一个nacos服务中心，并且注册了一个服务，下面我们来看在上一篇文章的基础上，怎样用Openfeign来调用这个服务。

0.同上篇，启动nacos

 

1.搭建alibaba spring cloud脚手架

访问https://start.aliyun.com/bootstrap.html,GroupID: com.alibaba.cloud,Artifact:nocos-discovery-consumer-sample。,选择依赖：Nacos Service Discovery,Spring Web,Cloud Bootstrap. 

 

2.在pom文件中引入spring-cloud-starter-loadbalancer,注意一定要引入loadbalancer,否则用openfeign调用会报错。

完整的pom文件如下：

<?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>2.6.11</version>         <relativePath/> <!-- lookup parent from repository -->     </parent>     <groupId>com.alibaba.cloud</groupId>     <artifactId>nocos-discovery-consumer-sample</artifactId>     <version>0.0.1-SNAPSHOT</version>     <name>nocos-discovery-consumer-sample</name>     <description>Demo project for Spring Boot</description>      <properties>         <java.version>1.8</java.version>         <spring-cloud-alibaba.version>2021.0.4.0</spring-cloud-alibaba.version>         <spring-cloud.version>2021.0.4</spring-cloud.version>     </properties>      <dependencies>         <dependency>             <groupId>org.springframework.boot</groupId>             <artifactId>spring-boot-starter-web</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</artifactId>         </dependency>          <dependency>             <groupId>org.springframework.boot</groupId>             <artifactId>spring-boot-starter-test</artifactId>             <scope>test</scope>         </dependency>           <dependency>     <groupId>org.springframework.cloud</groupId>     <artifactId>spring-cloud-starter-openfeign</artifactId> </dependency>           <dependency>             <groupId>org.springframework.cloud</groupId>             <artifactId>spring-cloud-starter-loadbalancer</artifactId>             <version>3.0.1</version>         </dependency>      </dependencies>      <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>      <build>         <plugins>             <plugin>                 <groupId>org.apache.maven.plugins</groupId>                 <artifactId>maven-compiler-plugin</artifactId>                 <version>3.8.1</version>                 <configuration>                     <source>1.8</source>                     <target>1.8</target>                     <encoding>UTF-8</encoding>                 </configuration>             </plugin>             <plugin>                 <groupId>org.springframework.boot</groupId>                 <artifactId>spring-boot-maven-plugin</artifactId>             </plugin>         </plugins>     </build>  </project>

 3.配置application.properties

spring.application.name=nocos-discovery-consumer-sample spring.cloud.nacos.discovery.username=nacos spring.cloud.nacos.discovery.password=nacos spring.cloud.nacos.discovery.server-addr=localhost:8848 spring.cloud.nacos.discovery.namespace=public spring.main.allow-circular-references=true server.port=9091

注意这一行：spring.cloud.nacos.discovery.server-addr=localhost:8848 ，表明这是nacos服务中心的地址。

4.新建一个Openfeign调用类：

import org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.*; import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClient;  @FeignClient("nocos-discovery-provider-sample")  @LoadBalancerClient("nocos-discovery-provider-sample") public interface EchoService {               @GetMapping("/echo/{message}")      public String callEcho(@PathVariable String message);      }

这里要注意的是标注@LoadBalancerClient("nocos-discovery-provider-sample")，nocos-discovery-provider-sample就是上一篇中服务提供方注册到nacos的名称.

 

5.新建一个Controller:

@RestController public class RestTemplateController {              @Autowired      private EchoService echoService;            @GetMapping("/call/echo/{message}")      public String callEcho(@PathVariable String message) {                    //openFeign test          return "From openFeign :"+echoService.callEcho(message);                                   } }

6.SpringBoot启动类：

import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication;  import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.openfeign.EnableFeignClients;  @SpringBootApplication @EnableDiscoveryClient @EnableFeignClients public class NocosDiscoveryConsumerSampleApplication {      public static void main(String[] args) {         SpringApplication.run(NocosDiscoveryConsumerSampleApplication.class, args);     }  }

记得要加标注@EnableFeignClients

 

7.访问http://localhost:9091/call/echo/hello