nacos实现Java和.NetCore的服务注册和调用

用nacos作为服务注册中心，如何注册.NetCore服务，如何在Java中调用.NetCore服务呢？可以分为下面几个步骤：

0.运行nacos

1.开发.net core服务，然后调用nacos提供的.net core sdk注册服务。

2.开发Java服务，然后注册服务。

3.用RestTemplate调用.net core服务。

下面来看代码：

0.参考我之前的文章分布式配置nacos搭建踩坑指南(下)，首先运行nacos.

1.首先开发一个.net core web api,我们返回的数据是天气预报消息，新建一个WeatherForecastController,代码如下：

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
​
namespace WebApi.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class WeatherForecastController : ControllerBase
    {
        private static readonly string[] Summaries = new[]
        {
            "Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
        };
​
        private readonly ILogger<WeatherForecastController> _logger;
​
        public WeatherForecastController(ILogger<WeatherForecastController> logger)
        {
            _logger = logger;
        }
​
        [HttpGet]
        public IEnumerable<WeatherForecast> Get()
        {
            var rng = new Random();
            return Enumerable.Range(1, 5).Select(index => new WeatherForecast
            {
                Date = DateTime.Now.AddDays(index),
                TemperatureC = rng.Next(-20, 55),
                Summary = Summaries[rng.Next(Summaries.Length)]
            })
            .ToArray();
        }
        //public String Get()
        //{
        //    return "sunny";
        //}
​
    }
}

然后设置好访问的url,在launchSettings.json的修改 "applicationUrl": "http://192.168.1.110:5000"，注意这里去掉了https://192.168.1.110:5001,是为了避免在后面Java调用时需要证书的麻烦。

最后我们在cmd中输入dotnet run，当服务正常运行起来后，在浏览器中输入：http://192.168.1.110:5000/weatherforecast，发现成功返回天气数据，格式为json,截图如下：

2.net core项目中引入nuget包：nacos-sdk-csharp，截图如下：

3.调用nacos-sdk-csharp，进行服务注册，代码如下：

using System;
using Microsoft.Extensions.DependencyInjection;
using Nacos.V2;
using Nacos.V2.DependencyInjection;
using System.Collections.Generic;
using System.Threading.Tasks;
namespace NacosDiscoveryProviderNetCoreTest1
{
    class Program
    {
        static async Task Main(string[] args)
        {
            string serverAddr = "http://localhost:8848";
            string dataId = "config2";
            string group = "DEFAULT_GROUP";
​
            IServiceCollection services = new ServiceCollection();
            //register service
            services.AddNacosV2Naming(
                 x =>
                 {
                     x.ServerAddresses = new List<string>() { serverAddr };
                     //x.ConfigUseRpc = true;
​
                 }
                );
            IServiceProvider serviceProvider = services.BuildServiceProvider();
            var namingSvc = serviceProvider.GetService<INacosNamingService>();
            await namingSvc.RegisterInstance("weatherforecast", "192.168.1.110", 5000);
            Console.WriteLine(Newtonsoft.Json.JsonConvert.SerializeObject(await namingSvc.GetAllInstances("weatherforecast")));
            Console.ReadKey();
​
​
        }
    }
}

我们进入nacos后台，如果服务注册成功，我们就会在服务列表中看到weatherforecast服务了，如下所示：

有两个地方必须切记注意：

1).namingSvc.RegisterInstance("weatherforecast", "192.168.1.110", 5000);是一句很关键的代码，意思是注册一个名为weatherforecast，地址为：192.168.1.110，端口为:5000的服务。

2)launchSettings.json里的applicationUrl必须去掉包含https的设置，只保留http的设置，即只保留："applicationUrl": "http://192.168.1.110:5000"，否则在Java中调用会报证书错误。

4.参考nacos服务注册，利用阿里巴巴Spring boot脚手架，引入：spring-boot-starter-web，spring-cloud-starter-alibaba-nacos-discovery，spring-cloud-starter，spring-boot-starter-test，spring-cloud-starter-loadbalancer，spring-cloud-starter-openfeign。完整的pom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>
        <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.47</version>
</dependency>
​
​
​
<dependency>
<groupId>org.netbeans.external</groupId>
<artifactId>org-apache-commons-httpclient</artifactId>
<version>RELEASE126</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>

5.application.properties的设置同前面的文章里介绍的设置一样，代码如下所示：

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

6.新建一个名为WeatherService的接口，代码如下：

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.cloud.loadbalancer.annotation.LoadBalancerClient;
​
​
@FeignClient("weatherforecast")
@LoadBalancerClient("weatherforecast")
public interface WeatherService {
​
  @GetMapping("/Weatherforecast")
  public String getWeather();

}

7.新建一个RestTemplateController，代码如下：

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
​
import com.alibaba.fastjson.JSONObject;
​
import org.springframework.context.annotation.Bean;
import org.apache.commons.httpclient.methods.GetMethod;
//import org.apache.http.client.HttpClient;
import org.apache.commons.httpclient.HttpClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import java.io.*;
​
​
​
@RestController
public class RestTemplateController {
​
   //@LoadBalanced
   @Autowired
   public RestTemplate resttemplate;

   //@LoadBalanced
   @Bean
   public RestTemplate restTemplate() {
     return new RestTemplate();
   }

   @Autowired
   private EchoService echoService;

   @Autowired
   private WeatherService weatherService;

   @Autowired DiscoveryClient discoveryClient;

   //resttemplate test
   @GetMapping("/call/echo")
   public String callEcho() { 

     System.out.println("callEcho");

     ServiceInstance serviceInstance=discoveryClient.getInstances("weatherforecast").get(0);
     System.out.println("Host is: "+serviceInstance.getHost()+" ,port is: "+serviceInstance.getPort());
         String urlString=serviceInstance.getHost()+":"+serviceInstance.getPort()+"/weatherforecast";
     urlString="http://"+urlString;
     //RestTemplate test
     return resttemplate.getForObject(urlString, String.class);

   }

   //openFeign test
   @GetMapping("/getWeather")
   public String getWeather() {

     return weatherService.getWeather();
​
   }
}

其中要注意的几点：

1) ServiceInstanceserviceInstance=discoveryClient.getInstances("weatherforecast").get(0);是一句关键的代码，用于获取weatherforecast服务的实例。

2)callEcho()是调用RestTemplage访问netcore服务

3)getWeather是调用openFeiign访问netcore服务

8.启动类代码如下：

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);
    }
​
}

9.运行，访问http://192.168.1.110:5000/weatherforecast和http://localhost:9091/getWeather：