【Nacos学习】二、整合OpenFeign组件_nacos fegin学习

功能实现

创建项目

创建【nacos-feign】子服务，用于测试OpenFeign组件的使用，其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>
        <artifactId>nacos</artifactId>
        <groupId>com.kongcheng</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
 
    <groupId>com.kongcheng</groupId>
    <artifactId>nacos-feign</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>nacos-feign</name>
    <description>Demo project for Spring Boot</description>
 
    <properties>
        <java.version>1.8</java.version>
    </properties>
 
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- 在微服务中引入openfeign的依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
    </dependencies>
 
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <version>2.3.0.RELEASE</version>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
 
</project>

主入口添加【@EnableDiscoveryClient】用作开启服务注册，【@EnableFeignClients】作为开启OpenFeign：

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//开启服务注册
@EnableFeignClients//开启OpenFeign
public class NacosFeignApplication {
 
    public static void main(String[] args) {
        SpringApplication.run(NacosFeignApplication.class, args);
    }
 
}

配置文件如下：

server:
  port: 18202
spring:
  application:
    name: nacos-feign
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848 # Nacos作为服务注册中心地址

定义远程接口

创建名为【api】的Package，如下所示：

 创建RemoteClient接口，来定义OpenFeign要调用的远程服务接口：

调用的是前面创建的【nacos-provide】子服务中的方法，需要注意方法名需要与远程服务名相同

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
 
@FeignClient(name = "nacos-provide",fallback = RemoteHystrix.class)
public interface RemoteClient {
 
    @GetMapping("/helloNacos")
    String helloNacos();
}

创建RemoteHystrix接口，来进行熔断降级处理

import org.springframework.stereotype.Component;
 
/**
 * 服务降级处理
 */
@Component
public class RemoteHystrix implements RemoteClient{
 
    public String helloNacos() {
        return "请求超时了!";
    }
}

具体调用OpenFeign测试

创建【TestController】控制层：

import com.kongcheng.nacosfeign.api.RemoteClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
 
@RestController
public class TestController {
 
    @Autowired
    private RemoteClient remoteClient;
 
    @GetMapping("/feign")
    public String test() {
        return remoteClient.helloNacos();
    }
}

完成后启动服务。

测试

需要启动【Nacos-server】,【nacos-provide】，【nacos-feign】，启动成功后浏览器访问:localhost:18202/feign，可以通过OpenFeign远程调用nacos-provide的接口

项目源码

https://gitee.com/dukeLiuyu/nacos