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注册中心原理

一、环境准备

Java版本：1.8+ (Linux centos7虚拟机下安装Jdk1.8)
MySQL服务：5.6.5+ (Linux Centos7 安装MySQL5.7 图文详解)

二、创建项目

2.1 创建项目父工程

IDEA中创建聚合项目nacos作为父工程,其pom.xml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>

    <!--SpringBoot版本-->

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>2.3.3.RELEASE</version>

        <relativePath/> <!-- lookup parent from repository -->

    </parent>

    <groupId>com.example</groupId>

    <artifactId>nacos</artifactId>

    <version>0.0.1</version>

    <name>nacos</name>

    <description>Spring Cloud Nacos</description>

    <properties>

        <java.version>1.8</java.version>

    </properties>

    <!--引入子模块-->

    <modules>

        <module>provider</module><!--生产者-->

        <module>consumer</module><!--消费者-->

    </modules>

    <dependencies>

        <!--web依赖-->

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

        <!--测试依赖-->

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-test</artifactId>

            <scope>test</scope>

        </dependency>

        <!--nacos配置中心依赖-->

        <dependency>

            <groupId>com.alibaba.cloud</groupId>

            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>

            <version>2.1.1.RELEASE</version>

        </dependency>

        <!--nacos配置中心依赖-->

        <!--<dependency>-->

            <!--<groupId>org.springframework.cloud</groupId>-->

            <!--<artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>-->

            <!--<version>0.2.1.RELEASE</version>-->

        <!--</dependency>-->

        <!--lombok依赖-->

        <dependency>

            <groupId>org.projectlombok</groupId>

            <artifactId>lombok</artifactId>

            <optional>true</optional>

        </dependency>

        <!--注册中心依赖-->

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>

            <version>0.2.2.RELEASE</version>

        </dependency>

    </dependencies>

    <build>

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

        </plugins>

    </build>

    <dependencyManagement>

        <dependencies>

            <dependency>

                <groupId>org.springframework.cloud</groupId>

                <artifactId>spring-cloud-dependencies</artifactId>

                <version>Greenwich.SR2</version>

                <type>pom</type>

                <scope>import</scope>

            </dependency>

        </dependencies>

    </dependencyManagement>

</project>

2.2 创建Provider服务生产者

在父工程Nacos下创建springboot子工程provider，其pom.xml文件为：

<?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>

    <!--父工程-->

    <parent>

        <groupId>com.example</groupId>

        <artifactId>nacos</artifactId>

        <version>0.0.1</version>

        <relativePath/> <!-- lookup parent from repository -->

    </parent>

    <groupId>com.example</groupId>

    <artifactId>provider</artifactId>

    <version>0.0.1</version>

    <name>provider</name>

    <description>Provider Nacos</description>

    <properties>

        <java.version>1.8</java.version>

    </properties>

    <dependencies>

        <!--lombok依赖-->

        <dependency>

            <groupId>org.projectlombok</groupId>

            <artifactId>lombok</artifactId>

            <optional>true</optional>

        </dependency>

    </dependencies>

    <build>

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

        </plugins>

    </build>

</project>

在启动类ProviderApplication.java中增加@EnableDiscoveryClient注解

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication

@EnableDiscoveryClient//开启注册

public class ProviderApplication {

    public static void main(String[] args) {

        SpringApplication.run(ProviderApplication.class, args);

    }

}

配置文件application.yml进行如下配置

#生产者配置

server:

  port: 8081

spring:

  application:

    name: nacos-provider #服务名称

  cloud:

    nacos:

      discovery:  #使用注册中心

        server-addr: 192.168.36.135:8848 #Nacos访问地址

        enabled: true

在服务提供方创建一个对外接口

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RequestMapping("/provider")

@RestController

public class IndexController {

    @GetMapping("/hello")

    public String hello() {

        return "我是provider服务生产者";

    }

}

2.3 创建Consumer服务消费者

在父工程Nacos下创建springboot子工程consumer，其pom.xml文件为：

<?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>

    <!--父工程-->

    <parent>

        <groupId>com.example</groupId>

        <artifactId>nacos</artifactId>

        <version>0.0.1</version>

        <relativePath/> <!-- lookup parent from repository -->

    </parent>

    <groupId>com.example</groupId>

    <artifactId>consumer</artifactId>

    <version>0.0.1</version>

    <name>consumer</name>

    <description>Consumer Nacos</description>

    <properties>

        <java.version>1.8</java.version>

    </properties>

    <dependencies>

        <!--feign依赖-->

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-openfeign</artifactId>

        </dependency>

        <!--hystrix断路器-->

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>

        </dependency>

    </dependencies>

    <build>

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

        </plugins>

    </build>

</project>

在启动类ConsumerApplication.java中增加注解

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 //开启注册

@EnableFeignClients //开启Feign服务

public class ConsumerApplication {

    public static void main(String[] args) {

        SpringApplication.run(ConsumerApplication.class, args);

    }

}

配置文件application.yml进行如下配置

#消费者配置

server:

  port: 8082

spring:

  application:

    name: nacos-consumer

  cloud:

    nacos:

      discovery:  #使用注册中心

        server-addr: 192.168.36.135:8848

        enabled: true

#开启断路器

feign:

 hystrix:

   enabled: true

使用FeginClient进行服务调用,hystrix进行熔断

import com.example.consumer.hystrix.HystrixUtils;

import org.springframework.cloud.openfeign.FeignClient;

import org.springframework.web.bind.annotation.GetMapping;

@FeignClient(name = "nacos-provider",fallback = HystrixUtils.class)//服务出现异常进行容错

public interface ProviderFeignClient {

    /**

     * .

     * 调用生产者服务

     * @return

     */

    @GetMapping("/provider/hello")

    String hello();

}

HystrixUtils.class容错类

import com.example.consumer.client.ProviderFeignClient;

import org.springframework.stereotype.Component;

@Component

public class HystrixUtils implements ProviderFeignClient {

    /**

     * .

     * 方法重写

     *

     * @return

     */

    @Override

    public String hello() {

        return "断路器容错,服务开小差了，稍等片刻...";

    }

}

service层服务调用

import com.example.consumer.client.ProviderFeignClient;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

@Service

public class IndexService {

    @Autowired

    private ProviderFeignClient client; //注入

    public String hello() {

        return client.hello(); // 服务调用

    }

}

在controller中调用service的接口,像一般的接口调用一样

import com.example.consumer.service.IndexService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

@RequestMapping("/consumer")

@RestController

public class IndexController {

    @Autowired

    private IndexService service;

    @GetMapping("/hello")

    public String hello(){

          return service.hello();

    }

}

三、服务调用测试

3.1 项目启动

启动完成后，在服务提供者和消费者的日志中应该可以分别看到如下信息

INFO 18388 --- [           main] o.s.c.a.n.registry.NacosServiceRegistry  : nacos registry, nacos-provider 192.168.22.1:8081 register finished

3.2 登录Nacos控制台

你会发现服务列表中，已经显示了我们刚才创建的两个项目，并可以对其进行简单的监控和管理。

3.3 使用样例项目

打开浏览器输入：http://localhost:8082/consumer/hello

Nacos服务发现与Eureak服务发现无差异

敬请关注下篇保姆教程系列三、Nacos Config–服务配置中心

总结：

我是南国以南i记录点滴每天成长一点点，学习是永无止境的！转载请附原文链接！！！

参考链接

巴特西

保姆教程系列二、Nacos实现注册中心

前言：