从spring boot到spring cloud（四）Spring Cloud Eureka 注册与发现

朱雀 2022-12-29 11:22 194阅读 0赞

在搭建Spring Cloud Eureka环境前先要了解整个架构的组成，常用的基础模式如下图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RlcnJ5NzEx_size_16_color_FFFFFF_t_70]  
服务提供者：将springboot服务编写好以后，通过配置注册中心地址方式注册，提供给消费者使用。  
注册中心：服务的中间桥梁，服务提供者将服务注册。服务消费者可以通过注册信息调用需要使用的服务。  
服务消费者：通过规定的调用方式，读取注册中心的注册信息，调用相应的服务。

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RlcnJ5NzEx_size_16_color_FFFFFF_t_70 1]  
根据后续的服务复杂度进化以后，可以看到服务提供者也可以是服务消费者，服务消费者也可以是服务提供者。根据不同的业务情况是可以互相调用的。

下面来搭建一个基础的eureka。环境还是使用的之前的spring官方下载的。

**内容写的比较详细，可以跟这一步步操作。**

# 一、注册中心 #

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RlcnJ5NzEx_size_16_color_FFFFFF_t_70 2]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RlcnJ5NzEx_size_16_color_FFFFFF_t_70 3]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RlcnJ5NzEx_size_16_color_FFFFFF_t_70 4]

![在这里插入图片描述][2020122214243211.png]  
以下是几个需要修改和添加的地方，后面会有完整的pom.xml

<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.1.3.RELEASE</version>
    		<relativePath /> 
    	</parent>
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Finchley.SR2</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    		</dependency>
    
    		
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-actuator</artifactId>
    		</dependency>

<table> 
 <thead> 
  <tr> 
   <th>Spring Cloud</th> 
   <th>Spring Boot</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>Angel版本</td> 
   <td>兼容Spring Boot 1.2.x</td> 
  </tr> 
  <tr> 
   <td>Brixton版本</td> 
   <td>兼容Spring Boot 1.3.x，也兼容Spring Boot 1.4.x</td> 
  </tr> 
  <tr> 
   <td>Camden版本</td> 
   <td>兼容Spring Boot 1.4.x，也兼容Spring Boot 1.5.x</td> 
  </tr> 
  <tr> 
   <td>Dalston版本、Edgware版本</td> 
   <td>兼容Spring Boot 1.5.x，不兼容Spring Boot 2.0.x</td> 
  </tr> 
  <tr> 
   <td>Finchley版本</td> 
   <td>兼容Spring Boot 2.0.x，不兼容Spring Boot 1.5.x</td> 
  </tr> 
  <tr> 
   <td>Greenwich版本</td> 
   <td>兼容Spring Boot 2.1.x</td> 
  </tr> 
 </tbody> 
</table>

**这里采用Finchley.SR2版本 springboot版本改成 2.1.3.RELEASE**

完整的pom.xml

<?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>2.1.3.RELEASE</version>
    		<relativePath /> 
    	</parent>
    	<groupId>com.example</groupId>
    	<artifactId>eureka1</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<name>eureka1</name>
    	<description>Demo project for Spring Boot</description>
    
    	<properties>
    		<java.version>1.8</java.version>
    	</properties>
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Finchley.SR2</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-server</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>
    			<exclusions>
    				<exclusion>
    					<groupId>org.junit.vintage</groupId>
    					<artifactId>junit-vintage-engine</artifactId>
    				</exclusion>
    			</exclusions>
    		</dependency>
    	</dependencies>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

package com.example.demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
    
    @EnableEurekaServer
    @SpringBootApplication
    public class Eureka1Application { 
    
    	public static void main(String[] args) { 
    		SpringApplication.run(Eureka1Application.class, args);
    	}
    
    }

然后在代码文件中添加@EnableEurekaServer注解

修改application.yml文件

server:
      port: 3000 # 端口
    eureka:
      instance:
        hostname: eureka-center 
        appname: 注册中心
      client:
        registerWithEureka: false # 单点的时候设置为 false 禁止注册自身
        fetchRegistry: false
        serviceUrl:
          defaultZone: http://localhost:3000/eureka
      server:
        enableSelfPreservation: false
        evictionIntervalTimerInMs: 4000

![在这里插入图片描述][20201222144944241.png]  
启动服务

浏览器输入 http://127.0.0.1:3000  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RlcnJ5NzEx_size_16_color_FFFFFF_t_70 5]  
证明注册中心搭建成功了

# 二、服务提供者 #

前面的步骤一样  
![在这里插入图片描述][20201222145822491.png]  
ProviderController是新建的一个服务代码

<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    		</dependency>

不同的地方有加了一个spring-boot-starter-web和spring-cloud-starter-netflix-eureka-client客户端  
完整的pom.xml

<?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>2.1.3.RELEASE</version>
    		<relativePath /> 
    	</parent>
    	<groupId>com.example</groupId>
    	<artifactId>eurekaClient1</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<name>eurekaClient1</name>
    	<description>Demo project for Spring Boot</description>
    
    	<properties>
    		<java.version>1.8</java.version>
    	</properties>
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Finchley.SR2</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    		</dependency>
    	</dependencies>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

EurekaClient1Application

package com.example.demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    
    @EnableEurekaClient
    @SpringBootApplication
    public class EurekaClient1Application { 
    
    	public static void main(String[] args) { 
    		SpringApplication.run(EurekaClient1Application.class, args);
    	}
    
    }

ProviderController

package com.example.demo;
    
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class ProviderController { 
    
        @RequestMapping(value = "/hello")
        public String hello(){ 
            
            return "hello spring cloud!";
        }
    
        @RequestMapping(value = "/nice")
        public String nice(){ 
            
            return "nice to meet you!";
        }
    }

application.yml

server:
      port: 3001
    
    eureka:
      instance:
        preferIpAddress: true
      client:
        serviceUrl:
          defaultZone: http://localhost:3000/eureka  ## 注册到 eureka 
    spring:
      application:
        name: single-provider  ## 应用程序名称，后面会在消费者中用到

![在这里插入图片描述][20201222150329778.png]  
http://127.0.0.1:3001/hello  
![在这里插入图片描述][20201222150509610.png]  
http://127.0.0.1:3000/  
![在这里插入图片描述][20201222150631439.png]  
证明服务已经注册成功

# 三、服务消费者 #

前面还是同上

![在这里插入图片描述][20201222153907244.png]

<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-openfeign</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    		</dependency>

pom.xml新增以上内容

完整pom.xml

<?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>2.1.3.RELEASE</version>
    		<relativePath /> 
    	</parent>
    	<groupId>com.example</groupId>
    	<artifactId>eurekaClient1</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<name>eurekaClient1</name>
    	<description>Demo project for Spring Boot</description>
    
    	<properties>
    		<java.version>1.8</java.version>
    	</properties>
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Finchley.SR2</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-openfeign</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    		</dependency>
    	</dependencies>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    
    </project>

EurekaClient2Application

package com.example.demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.loadbalancer.LoadBalanced;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    import org.springframework.cloud.openfeign.EnableFeignClients;
    import org.springframework.context.annotation.Bean;
    import org.springframework.web.client.RestTemplate;
    
    @EnableEurekaClient
    @EnableFeignClients
    @SpringBootApplication
    public class EurekaClient2Application { 
    
    	/** * 注入 RestTemplate * 并用 @LoadBalanced 注解，用负载均衡策略请求服务提供者 * 这是 Spring Ribbon 的提供的能力 * @return */
        @LoadBalanced
        @Bean
        public RestTemplate restTemplate() { 
            return new RestTemplate(); //用于调用服务对象
        }
    	
    	public static void main(String[] args) { 
    		SpringApplication.run(EurekaClient2Application.class, args);
    	}
    
    }

ConsumerController

package com.example.demo;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.client.RestTemplate;
    
    @RestController
    public class ConsumerController { 
    	@Autowired
        private RestTemplate restTemplate;
    
        private static final String applicationName = "single-provider";//服务注册名
    
        @RequestMapping(value = "commonRequest")
        public Object commonRequest(){ 
            String url = "http://"+ applicationName +"/hello";
            String s = restTemplate.getForObject(url,String.class);//Ribbon方式调用服务
            return s;
        }
    }

application.yml

server:
      port: 3002
    eureka:
      client:
        serviceUrl:
          defaultZone: http://127.0.0.1:3000/eureka  ## 注册到 eureka
      instance:
        preferIpAddress: true
    spring:
      application:
        name: single-customer

![在这里插入图片描述][20201222154146531.png]  
启动服务  
http://127.0.0.1:3002/commonRequest  
![在这里插入图片描述][20201222154306707.png]  
返回服务提供者的 hello方法参数。

整个最简单的过程就完成了，需要更好的使用spring cloud 后续需要了解分布式、负载均衡、熔断等概念。在后续章节将一步步的拆分。

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RlcnJ5NzEx_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20201222113919268.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RlcnJ5NzEx,size_16,color_FFFFFF,t_70
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[2020122214243211.png]: https://img-blog.csdnimg.cn/2020122214243211.png
[20201222144944241.png]: https://img-blog.csdnimg.cn/20201222144944241.png
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[20201222145822491.png]: https://img-blog.csdnimg.cn/20201222145822491.png
[20201222150329778.png]: https://img-blog.csdnimg.cn/20201222150329778.png
[20201222150509610.png]: https://img-blog.csdnimg.cn/20201222150509610.png
[20201222150631439.png]: https://img-blog.csdnimg.cn/20201222150631439.png
[20201222153907244.png]: https://img-blog.csdnimg.cn/20201222153907244.png
[20201222154146531.png]: https://img-blog.csdnimg.cn/20201222154146531.png
[20201222154306707.png]: https://img-blog.csdnimg.cn/20201222154306707.png