前言

本节通过实现一个简单的 echo service 演示如何在您的 Spring Cloud 项目中启用 Nacos 的服务注册和发现功能，如下图示:

一、提供者

1. 引入依赖

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

2.配置 Nacos Server 地址

${NACOS_SERVER_ADDR}是配置的环境变量

server:
  port: 9002
spring:
  application:
    name: provider-service
  cloud:
    nacos:
      discovery:
        server-addr: ${NACOS_SERVER_ADDR}
        username: nacos
        password: nacos

在使用 Nacos 服务发现和配置功能时，一定要配置 username 和 password 属性，否则会出现用户未找到异常！

3. 开启服务注册

package org.example.nacos.provider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@EnableDiscoveryClient
@SpringBootApplication
public class NacosDiscoveryProviderApplication {

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

}

二、消费者

1. 引入依赖

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

2.配置 Nacos Server 地址

server:
  port: 9000
spring:
  application:
    name: consumer-service
  cloud:
    nacos:
      discovery:
        server-addr: ${NACOS_SERVER_ADDR}
        username: nacos
        password: nacos

3. 开启服务注册

package org.example.nacos.consumer;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@EnableDiscoveryClient
@SpringBootApplication
public class NacosDiscoveryConsumerApplication {

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

}

三、服务列表

四、服务发现

1. 获取服务列表

我们在消费者项目中获取nacos中的服务列表，并打印出来。

package org.example.nacos.consumer.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

/**
 * Create by zjg on 2024/7/15
 */
@RequestMapping("/nacos/")
@RestController
public class NacosDiscoveryController {
    @Autowired
    DiscoveryClient discoveryClient;
    @RequestMapping("discovery")
    public void discovery(){
        List<String> services = discoveryClient.getServices();
        services.forEach(System.out::println);
    }
    @RequestMapping("discovery/instance")
    public void discovery(@RequestParam("serviceId") String serviceId){
        List<ServiceInstance> instances = discoveryClient.getInstances(serviceId);
        instances.forEach(instance->{
            System.out.println(instance.getHost()+":"+instance.getPort());
        });
    }
}

新版本的@RequestParam(“serviceId”)，用法略有改动，更加规范了，但是没那么灵活对开发者不是很友好！

2. 测试

2.1 获取所有服务

http://localhost:9000/nacos/discovery

consumer-service
provider-service

2.2 根据服务名获取服务信息

http://localhost:9000/nacos/discovery/instance?serviceId=provider-service

192.168.0.103:9002

五、更多配置项

总结

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