Spring Cloud Eureka 註冊與發現操作步驟詳解

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在搭建Spring Cloud Eureka環境前先要瞭解整個架構的組成，常用的基礎模式如下圖：

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服務提供者：將springboot服務編寫好以後，通過配置註冊中心地址方式註冊，提供給消費者使用。
註冊中心：服務的中間橋梁，服務提供者將服務註冊。服務消費者可以通過註冊信息調用需要使用的服務。
服務消費者：通過規定的調用方式，讀取註冊中心的註冊信息，調用相應的服務。

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根據後續的服務復雜度進化以後，可以看到服務提供者也可以是服務消費者，服務消費者也可以是服務提供者。根據不同的業務情況是可以互相調用的。

下面來搭建一個基礎的eureka。環境還是使用的之前的spring官方下載的。

內容寫的比較詳細，可以跟這一步步操作。

一、註冊中心

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以下是幾個需要修改和添加的地方，後面會有完整的pom.xml

<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.3.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</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>
<!-- 最新版的 eureka 服務端包 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
		</dependency>

		<!-- 監控管理 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-actuator</artifactId>
		</dependency>
Spring Cloud Spring Boot
Angel版本 兼容Spring Boot 1.2.x
Brixton版本 兼容Spring Boot 1.3.x，也兼容Spring Boot 1.4.x
Camden版本 兼容Spring Boot 1.4.x，也兼容Spring Boot 1.5.x
Dalston版本、Edgware版本 兼容Spring Boot 1.5.x，不兼容Spring Boot 2.0.x
Finchley版本 兼容Spring Boot 2.0.x，不兼容Spring Boot 1.5.x
Greenwich版本 兼容Spring Boot 2.1.x

這裡采用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 /> <!-- lookup parent from repository -->
	</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>
		<!-- 最新版的 eureka 服務端包 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
		</dependency>

		<!-- 監控管理 -->
		<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);
	}

}

然後在代碼文件中添加@EnableEurekaServer註解

修改application.yml文件

server:
 port: 3000 # 端口
eureka:
 instance:
 hostname: eureka-center 
 appname: 註冊中心
 client:
 registerWithEureka: false # 單點的時候設置為 false 禁止註冊自身
 fetchRegistry: false
 serviceUrl:
 defaultZone: http://localhost:3000/eureka
 server:
 enableSelfPreservation: false
 evictionIntervalTimerInMs: 4000

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啟動服務

瀏覽器輸入 http://127.0.0.1:3000

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證明註冊中心搭建成功瞭

二、服務提供者

前面的步驟一樣

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ProviderController是新建的一個服務代碼

<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>
		<!-- eureka 客戶端 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
		</dependency>

不同的地方有加瞭一個spring-boot-starter-web和spring-cloud-starter-netflix-eureka-client客戶端
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 /> <!-- lookup parent from repository -->
	</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>
		<!-- eureka 客戶端 -->
		<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 ## 註冊到 eureka 
spring:
 application:
 name: single-provider ## 應用程序名稱，後面會在消費者中用到

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http://127.0.0.1:3001/hello

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http://127.0.0.1:3000/

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證明服務已經註冊成功

三、服務消費者

前面還是同上

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<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>
		<!-- eureka 客戶端 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
		</dependency>

pom.xml新增以上內容

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 /> <!-- lookup parent from repository -->
	</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>
		<!-- eureka 客戶端 -->
		<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 {

	/**
 * 註入 RestTemplate 
 * 並用 @LoadBalanced 註解，用負載均衡策略請求服務提供者
 * 這是 Spring Ribbon 的提供的能力
 * @return
 */
 @LoadBalanced
 @Bean
 public RestTemplate restTemplate() {
 return new RestTemplate(); //用於調用服務對象
 }
	
	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";//服務註冊名

 @RequestMapping(value = "commonRequest")
 public Object commonRequest(){
 String url = "http://"+ applicationName +"/hello";
 String s = restTemplate.getForObject(url,String.class);//Ribbon方式調用服務
 return s;
 }
}

application.yml

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

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啟動服務
http://127.0.0.1:3002/commonRequest

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返回服務提供者的 hello方法參數。

整個最簡單的過程就完成瞭，需要更好的使用spring cloud 後續需要瞭解分佈式、負載均衡、熔斷等概念。在後續章節將一步步的拆分。

到此這篇關於Spring Cloud Eureka 註冊與發現操作步驟詳解的文章就介紹到這瞭,更多相關Spring Cloud Eureka 註冊內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet！

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