【SpringCloudAlibaba】nacos注册中心（一）实现feign远程调用

（尊重版权，内容学习来源于蚂蚁课堂）

本文开始记录SpringCloudAlibaba，使用SpringBoot2.0+，注册中心使用nacos（windows版本）

官网 ：https://nacos.io/zh-cn/docs/what-is-nacos.html

 工程初步结构：

本文使用到的Module: nacos-users（服务消费者）  nacos-service-server-data（服务生产者）

1.创建工程

   根pom.xml

    4.0.0

    springboot-nacos
    springboot-nacos
    pom
    1.0-SNAPSHOT
    
        nacos-service
        nacos-app
        nacos-users
        nacos-auth
        nacos-common
        nacos-gateway
    

    
        org.springframework.boot
        spring-boot-starter-parent
        2.1.1.RELEASE
        
    

    
        2.1.1.RELEASE
        2.1.1
        Greenwich.RELEASE
        1.2.47
        1.16.22
        1.8
        true
    

    
        
            com.alibaba
            fastjson
            ${fast.json.version}
        
        
            org.projectlombok
            lombok
            ${lombok.version}
            true
        

        
            org.springframework.cloud
            spring-cloud-dependencies
            ${spring-cloud.version}
            pom
            import
        

        
        
            com.netflix.archaius
            archaius-core
            0.7.6
            
                
                    com.google.guava
                    guava
                
            
        
    

2.创建空module  nacos-service  nacos-service-api

   创建api模块 nacos-service-api-data

   nacos-service-api pom配置：

    
        nacos-service
        springboot-nacos
        1.0-SNAPSHOT
    
    4.0.0

    nacos-service-api
    pom
    
        nacos-service-api-data
        nacos-service-api-rbac
    

    
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
            2.1.1.RELEASE
        
    

3.nacos-service-api-data 编写简单的接口 

package com.google.api;


import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;

@FeignClient(value = "nacos-service-server-data")
public interface HelloWorldService {

    @GetMapping("/helloWorld")
    String helloWorld(@RequestParam("age") Integer age);
}

4.创建空module nacos-service-server

pom配置文件

    
        nacos-service
        springboot-nacos
        1.0-SNAPSHOT
    
    4.0.0

    nacos-service-server
    pom
    
        nacos-service-server-data
    

    
        
            org.springframework.cloud
            spring-cloud-starter-alibaba-nacos-discovery
            0.9.0.RELEASE
            true
        
        
            org.springframework.boot
            spring-boot-starter-web
        
    

5.创建服务工程module nacos-service-server-data

pom配置文件

    
        nacos-service-server
        springboot-nacos
        1.0-SNAPSHOT
    
    4.0.0

    nacos-service-server-data

    
        
            springboot-nacos
            nacos-service-api-data
            1.0-SNAPSHOT
        
    

编写接口实现类：

package com.google.data.impl;

import com.google.api.HelloWorldService;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author wk
 * @Description:
 * @date 2020/3/3 13:12
 **/
@RestController
public class HelloWorldServiceImpl implements HelloWorldService {

    @Override
    public String helloWorld(Integer age) {
        return "hello world!" + " " + age;
    }
}

服务启动类：

package com.google;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

/**
 * @author wk
 * @Description:
 * @date 2020/3/2 16:06
 **/
@SpringBootApplication
public class DataServiceApplication {

    public static void main(String[] args) {
        SpringApplication.run(DataServiceApplication.class, args);
    }
}

yml配置文件：

spring:
  cloud:
    nacos:
      discovery:
        ###服务注册地址
        server-addr: 127.0.0.1:8848
  application:
    name: nacos-service-server-data
server:
  port: 8081

logging:
  path: F:/idea_workspace/springboot-nacos/logs/${spring.application.name}

6.创建服务调用方-测试服务nacos-users

pom配置

    
        springboot-nacos
        springboot-nacos
        1.0-SNAPSHOT
    
    4.0.0

    nacos-users

    
        
            org.springframework.cloud
            spring-cloud-starter-alibaba-nacos-discovery
            0.9.0.RELEASE
            true
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            springboot-nacos
            nacos-service-api-data
            1.0-SNAPSHOT
            compile
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
            2.1.1.RELEASE
        
    

yml配置：

spring:
  cloud:
    nacos:
      discovery:
        ###服务注册地址
        server-addr: 127.0.0.1:8848
  application:
    name: nacos-users
server:
  port: 8091

logging:
  path: F:/idea_workspace/springboot-nacos/logs/${spring.application.name}

启动类：

package com.google;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.openfeign.EnableFeignClients;

/**
 * @author wk
 * @Description:
 * @date 2020/3/2 20:49
 **/
@SpringBootApplication
@EnableFeignClients
public class NacosCustUacApplication {

    public static void main(String[] args) {
        SpringApplication.run(NacosCustUacApplication.class, args);
    }
}

调用feign服务类：

package com.google.service;

import com.google.api.HelloWorldService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author wk
 * @Description:
 * @date 2020/3/3 13:21
 **/
@RestController
public class HelloService {

    @Autowired
    private HelloWorldService helloWorldService;

    /**
     * 调用feign服务
     *
     * @return
     */
    @GetMapping("/hello")
    public String hello() {
        String s = helloWorldService.helloWorld(99);
        return "feignclient调用 " + s;
    }
}

7.测试运行:

启动nacos,启动服务。

启动成功后，可在http://localhost:8848/nacos/#/serviceManagement?dataId=&group=&appName=&namespace=

页面看到两个服务

调用   /helloWorld

---

踩坑记录：

1.java.lang.ClassNotFoundException: com.netflix.config.CachedDynamicIntProperty

调用feign服务报错，Springboot2.1.1版本

参考解决方法https://blog.csdn.net/shenhonglei1234/article/details/101213519

2.nacos com.netflix.client.ClientException: Load balancer does not have available server for client: nacos-service-server-data

访问报错

@FeignClient("nacos-service-server-data")这样写就报上面那个错了

@FeignClient(value = "nacos-service-server-data")这样写就没问题。。。

参考：https://blog.csdn.net/weixin_34259232/article/details/92390854