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

巴特西

Nacos服务调用(基于Openfeign)

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