使用Nacos实现服务注册与发现

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什么是Nacos

Nacos 致力于帮助您发现、配置和管理微服务。Nacos 提供了一组简单易用的特性集，帮助您快速实现动态服务发现、服务配置、服务元数据及流量管理。

Nacos 帮助您更敏捷和容易地构建、交付和管理微服务平台。 Nacos 是构建以“服务”为中心的现代应用架构 (例如微服务范式、云原生范式) 的服务基础设施。

安装Nacos

Nacos 依赖 Java 环境来运行。如果您是从代码开始构建并运行 Nacos，还需要为此配置 Maven 环境，请确保是在以下版本环境中安装使用:

64 bit OS，支持 Linux/Unix/Mac/Windows，推荐选用 Linux/Unix/Mac。
64 bit JDK 1.8+
Maven 3.2.x+

下载并安装

# 下载源码
git clone https://github.com/alibaba/nacos.git

# 安装到本地仓库
cd nacos/
mvn -Prelease-nacos clean install -U

启动服务

cd distribution/target/nacos-server-0.9.0/nacos/bin
# Linux
./startup.sh -m standalone

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访问服务

打开浏览器访问：http://localhost:8848/nacos 默认账号密码： nacos/nacos ，可以进入Nacos的服务管理页面了。

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构建服务提供者接入Nacos

创建依赖管理项目

创建一个工程名为 spring-cloud-alibaba-dependencies 的项目，pom.xml 配置文件如下：

<?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 http://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>2.0.6.RELEASE</version>
    </parent>

    <groupId>com.dsy</groupId>
    <artifactId>spring-cloud-alibaba-dependencies</artifactId>
    <version>1.0.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <name>spring-cloud-alibaba-dependencies</name>
    <inceptionYear>2019-Now</inceptionYear>

    <properties>
        <!-- Environment Settings -->
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>

        <!-- Spring Settings -->
        <spring-cloud.version>Finchley.SR2</spring-cloud.version>
        <spring-cloud-alibaba.version>0.2.1.RELEASE</spring-cloud-alibaba.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <!-- Compiler 插件, 设定 JDK 版本 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <showWarnings>true</showWarnings>
                </configuration>
            </plugin>

            <!-- 打包 jar 文件时，配置 manifest 文件，加入 lib 包的 jar 依赖 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <configuration>
                    <archive>
                        <addMavenDescriptor>false</addMavenDescriptor>
                    </archive>
                </configuration>
                <executions>
                    <execution>
                        <configuration>
                            <archive>
                                <manifest>
                                    <!-- Add directory entries -->
                                    <addDefaultImplementationEntries>true</addDefaultImplementationEntries>
                                    <addDefaultSpecificationEntries>true</addDefaultSpecificationEntries>
                                    <addClasspath>true</addClasspath>
                                </manifest>
                            </archive>
                        </configuration>
                    </execution>
                </executions>
            </plugin>

            <!-- resource -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
            </plugin>
            <!-- install -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-install-plugin</artifactId>
            </plugin>
            <!-- clean -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-clean-plugin</artifactId>
            </plugin>

            <!-- ant -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-antrun-plugin</artifactId>
            </plugin>
            <!-- dependency -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
            </plugin>
        </plugins>

        <pluginManagement>
            <plugins>
                <!-- Java Document Generate -->
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-javadoc-plugin</artifactId>
                    <executions>
                        <execution>
                            <phase>prepare-package</phase>
                            <goals>
                                <goal>jar</goal>
                            </goals>
                        </execution>
                    </executions>
                </plugin>
                <!-- YUI Compressor (CSS/JS压缩) -->
                <!--<plugin>
                    <groupId>net.alchim31.maven</groupId>
                    <artifactId>yuicompressor-maven-plugin</artifactId>
                    <version>1.5.1</version>
                    <executions>
                        <execution>
                            <phase>prepare-package</phase>
                            <goals>
                                <goal>compress</goal>
                            </goals>
                        </execution>
                    </executions>
                    <configuration>
                        <encoding>UTF-8</encoding>
                        <jswarn>false</jswarn>
                        <nosuffix>true</nosuffix>
                        <linebreakpos>30000</linebreakpos>
                        <force>true</force>
                        <includes>
                            <include>**/*.js</include>
                            <include>**/*.css</include>
                        </includes>
                        <excludes>
                            <exclude>**/*.min.js</exclude>
                            <exclude>**/*.min.css</exclude>
                        </excludes>
                    </configuration>
                </plugin>-->
            </plugins>
        </pluginManagement>
        <!-- 资源文件配置 -->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <excludes>
                    <exclude>**/*.java</exclude>
                </excludes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>
    </build>
    <repositories>
        <repository>
            <id>aliyun-repos</id>
            <name>Aliyun Repository</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>

        <repository>
            <id>sonatype-repos</id>
            <name>Sonatype Repository</name>
            <url>https://oss.sonatype.org/content/groups/public</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>sonatype-repos-s</id>
            <name>Sonatype Repository</name>
            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
            <releases>
                <enabled>false</enabled>
            </releases>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>
    <pluginRepositories>
        <pluginRepository>
            <id>aliyun-repos</id>
            <name>Aliyun Repository</name>
            <url>http://maven.aliyun.com/nexus/content/groups/public</url>
            <releases>
                <enabled>true</enabled>
            </releases>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </pluginRepository>
    </pluginRepositories>
</project>

创建服务提供者

创建一个工程名为 spring-cloud-alibaba-nacos-provider 的项目，pom.xml 配置文件如下：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>com.dsy</groupId>
        <artifactId>spring-cloud-alibaba-dependencies</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../spring-cloud-alibaba-dependencies/pom.xml</relativePath>
    </parent>

    <artifactId>spring-cloud-alibaba-nacos-provider</artifactId>
    <packaging>jar</packaging>

    <name>spring-cloud-alibaba-nacos-provider</name>
    <inceptionYear>2019-Now</inceptionYear>

    <dependencies>
        <!-- Spring Boot Begin -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- Spring Boot End -->

        <!-- Spring Cloud Begin -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- Spring Cloud End -->
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.dsy.spring.cloud.alibaba.nacos.provider.NacosProviderApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

创建应用主类，并实现一个HTTP接口：

package com.dsy.spring.cloud.alibaba.nacos.provider;


import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;


/**
 * @author sanya deng
 * @version 1.0.0
 * @Title: NacosProviderApplication
 * @ProjectName SpringCloud
 * @Description: TODO
 * @email forestsancy@163.com
 * @date 2019-04-12 14:25
 */
@SpringBootApplication
@EnableDiscoveryClient
//通过 @EnableDiscoveryClient 注解表明是一个 Nacos 客户端
public class NacosProviderApplication {
    public static void main(String[] args) {
        SpringApplication.run(NacosProviderApplication.class, args);
    }

    @RestController
    public class EchoController {

        @GetMapping(value = "/echo/{message}")
        public String echo(@PathVariable String message) {
            return "Hello Nacos Discovery " + message;
        }
    }
}

内容非常简单，@SpringBootApplication定义是个Spring Boot应用；@EnableDiscoveryClient开启Spring Cloud的服务注册与发现，由于这里引入了spring-cloud-starter-alibaba-nacos-discovery模块，所以Spring Cloud Common中定义的那些与服务治理相关的接口将使用Nacos的实现。

application.yml

spring:
  application:
    name: nacos-provider
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848

server:
  port: 8081

management:
  endpoints:
    web:
      exposure:
        include: "*"

启动工程

通过浏览器访问 http://localhost:8848/nacos，即 Nacos Server 网址

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这里会显示当前注册的所有服务，以及每个服务的集群数目、实例数、健康实例数。点击详情，我们还能看到每个服务具体的实例信息，如下图所示：

图片.png

构建服务消费者接入Nacos

创建服务消费者

创建一个工程名为 spring-cloud-alibaba-nacos-consumer的项目，pom.xml 配置文件如下：

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>com.dsy</groupId>
        <artifactId>spring-cloud-alibaba-dependencies</artifactId>
        <version>1.0.0-SNAPSHOT</version>
        <relativePath>../spring-cloud-alibaba-dependencies/pom.xml</relativePath>
    </parent>

    <artifactId>spring-cloud-alibaba-nacos-consumer</artifactId>
    <packaging>jar</packaging>

    <name>spring-cloud-alibaba-nacos-consumer</name>
    <inceptionYear>2019-Now</inceptionYear>

    <dependencies>
        <!-- Spring Boot Begin -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!-- Spring Boot End -->

        <!-- Spring Cloud Begin -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- Spring Cloud End -->
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>com.dsy.spring.cloud.alibaba.nacos.consumer.NacosConsumerApplication</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

Application

package com.dsy.spring.cloud.alibaba.nacos.consumer;

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

/**
 * @author sanya deng
 * @version 1.0.0
 * @Title: NacosConsumerApplication
 * @ProjectName SpringCloud
 * @Description: 服务消费者
 * @email forestsancy@163.com
 * @date 2019-04-12 15:32
 */
@SpringBootApplication
@EnableDiscoveryClient
public class NacosConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(NacosConsumerApplication.class, args);
    }
}

Configuration

创建一个名为 NacosConsumerConfiguration 的 Java 配置类，主要作用是为了注入 RestTemplate

package com.dsy.spring.cloud.alibaba.nacos.consumer.config;

/**
 * @author sanya deng
 * @version 1.0.0
 * @Title: NacosConsumerConfiguration
 * @ProjectName knowledge
 * @Description: Java 配置类
 * @email dengsy@bonatone.com
 * @date 2019-04-12 15:33
 */
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class NacosConsumerConfiguration {

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

Controller

创建Controller实现一个HTTP接口，在该接口中调用服务提供方的接口

package com.dsy.spring.cloud.alibaba.nacos.consumer.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

/**
 * @author sanya deng
 * @version 1.0.0
 * @Title: NacosConsumerController
 * @ProjectName SpringCloud
 * @Description: TODO
 * @email forestsancy@163.com
 * @date 2019-04-12 15:34
 */

@RestController
public class NacosConsumerController {

    @Autowired
    private LoadBalancerClient loadBalancerClient;

    @Autowired
    private RestTemplate restTemplate;

    @Value("${spring.application.name}")
    private String appName;

    @GetMapping(value = "/echo/app/name")
    public String echo() {
        //使用 LoadBalanceClient 和 RestTemplate 结合的方式来访问
        ServiceInstance serviceInstance = loadBalancerClient.choose("nacos-provider");
        String url = String.format("http://%s:%s/echo/%s", serviceInstance.getHost(), serviceInstance.getPort(), appName);
        return restTemplate.getForObject(url, String.class);
    }
}

这里使用了Spring Cloud Common中的LoadBalancerClient接口来挑选服务实例信息。然后从挑选出的实例信息中获取可访问的URI，拼接上服务提供方的接口规则来发起调用。

application.yml

spring:
  application:
    name: nacos-consumer
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848

server:
  port: 9091

management:
  endpoints:
    web:
      exposure:
        include: "*"

启动消费者

通过浏览器访问 http://localhost:8848/nacos，即 Nacos Server 网址

图片.png

可以发现多了一个名为 nacos-consumer 的服务，服务消费者成功注册到Nacos ;
然后通过curl或者postman等工具发起访问，下面以curl为例：

图片.png

curl http://localhost:9091/echo/app/name
Hello Nacos Discovery nacos-consumer

消费者成功调用了服务提供者的接口