Spring Cloud（一） Eureka 服务注册和发现

迈不过友情╰ 2022-03-14 11:16 248阅读 0赞

**这里采用springboot 2.1.3.RELEASE，springcloud Greenwich.RELEASE**

# **一、Eureka 服务注册中心** #

**1.maven依赖**

...
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> 
    </parent>
    
    ...
    <properties>
    	<java.version>1.8</java.version>
    	<spring-cloud.version>Greenwich.RELEASE</spring-cloud.version>
    </properties>
    
    ...
    
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </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>
        </dependencies>
    </dependencyManagement>

**2.新建配置文件application.yml **

*单节点配置*

*新建application-default.yml(这里方便一起说明故另新建application-default.yml,其实作为单节点直接在application.yml中添加即可)*

#独立eureka注册服务中心
    server:
      port: 7001
    
    spring:
      application:
        name: eureka-server
    
    eureka:
      instance:
        hostname: peer1
        instance-id: ${spring.application.name}:${spring.cloud.client.hostname}:${server.port}
      client:
        register-with-eureka: false     #由于该应用为注册中心,所以设置为false,代表不向注册中心注册自己
        fetch-registry: false #检索服务列表
        service-url:
          defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

*双节点配置*

*新建application-peer1.yml*

server:
      port: 7001
    
    spring:
      application:
        name: eureka-server
    
    eureka:
      instance:
        hostname: peer1
        instance-id: ${spring.application.name}:${spring.cloud.client.hostname}:${server.port}
      client:
        service-url:
          defaultZone: http://peer2:7002/eureka/

*新建application-peer2.yml*

server:
      port: 7002
    
    spring:
      application:
        name: eureka-server
    
    eureka:
      instance:
        hostname: peer2
        instance-id: ${spring.application.name}:${spring.cloud.client.hostname}:${server.port}
      client:
        service-url:
          defaultZone: http://peer1:7001/eureka/

![20190304143430776.png][]

*application.yml默认启动default单节点*

#并行eureka注册服务中心
    spring:
      profiles:
        active:
        - default

*window在[C:][C]\\Windows\\System32\\drivers\\etc\\hosts文件中添加如下*

127.0.0.1 peer1
    127.0.0.1 peer2

*liunx|centos   vi /etc/hosts 添加*

**3.启动类添加@EnableEurekaServer注解，开启Eureka服务发现的功能**

@SpringBootApplication
    @EnableEurekaServer
    public class SpringcloudEurekaApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(SpringcloudEurekaApplication.class, args);
    	}
    
    }

**4.java -jar的方式启动高可用Eureka Server**

*java -jar eureka.jar --spring.profiles.active=peer1*

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA5NTc2NDU_size_16_color_FFFFFF_t_70][]

*java -jar eureka.jar --spring.profiles.active=peer2*

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA5NTc2NDU_size_16_color_FFFFFF_t_70 1][]

# 二、Eureka 服务提供者 #

**1.maven依赖**

...
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.3.RELEASE</version>
        <relativePath/> 
    </parent>
    ...
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.RELEASE</spring-cloud.version>
    </properties>
    ...
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    
        <dependency>
    	    <groupId>org.springframework.boot</groupId>
    	    <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.56</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>
        </dependencies>
    </dependencyManagement>
    ...

**2.application.yml配置**

server:
      port: 7010
    
    spring:
      application:
        name: eureka-client
    
    eureka:
      instance:
        instance-id: ${spring.application.name}:${spring.cloud.client.hostname}:${server.port}
        status-page-url:  http://${spring.cloud.client.hostname}:${server.port}/demo
      client:
        register-with-eureka: true     #由于该应用为注册中心,所以设置为false,代表不向注册中心注册自己
        fetch-registry: true #检索服务列表
        service-url:
          defaultZone: http://peer1:7001/eureka/

**3.提供服务接口**

@RestController
    public class ClientController {
    	
    	@GetMapping("demo")
    	public Map<String,Object> demo(String params){
    		Map<String,Object> result = new HashMap<String,Object>();
    		result.put("code", "000000");
    		result.put("message", "调用成功");
    		JSONObject data = new JSONObject();
    		data.put("info", "提供服务方");
    		data.put("params", params==null?"":params);
    		result.put("data", data);
    		return result;		
    	}
    
    }

**4.启动类**

在使用服务发现的时候有两种注解，一种为@EnableDiscoveryClient，一种为@EnableEurekaClient，用法差不多

*spring cloud中discovery service有许多种实现（eureka、consul、zookeeper等等）  
@EnableDiscoveryClient基于spring-cloud-commons  
@EnableEurekaClient基于spring-cloud-netflix*

*就是如果选用的注册中心是eureka，那么就推荐@EnableEurekaClient，  
如果是其他的注册中心，那么推荐使用@EnableDiscoveryClient*

@SpringBootApplication
    @EnableEurekaClient
    public class SpringcloudClientApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(SpringcloudClientApplication.class, args);
    	}
    
    }

**5.eureka注册中心情况**

**eureka-7001**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA5NTc2NDU_size_16_color_FFFFFF_t_70 2][]

**eureka-7002**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA5NTc2NDU_size_16_color_FFFFFF_t_70 3][]

**页面结果**

![20190305150945206.png][]

[20190304143430776.png]: /images/20220313/03a0e3a98b554efb9a4c85e946ca2632.png
[C]: https://www.baidu.com/s?wd=C%3A&tn=24004469_oem_dg&rsv_dl=gh_pl_sl_csd
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA5NTc2NDU_size_16_color_FFFFFF_t_70]: /images/20220313/168098bc8b6f46b987dc9e8e4f53d043.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA5NTc2NDU_size_16_color_FFFFFF_t_70 1]: /images/20220313/144415a8b3124b29b5ea3de477b5cd5b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA5NTc2NDU_size_16_color_FFFFFF_t_70 2]: /images/20220313/eecbfd24d97c435b88c943f406cadc05.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3UwMTA5NTc2NDU_size_16_color_FFFFFF_t_70 3]: /images/20220313/ac92aa6324604aae8ae083005b71637b.png
[20190305150945206.png]: /images/20220313/e013c1a1af38465b9b99bf9d488e5ef6.png