SpringCloud 学习(3)：eureka集群

SpringCloud 学习(3)：eureka集群

*这篇文章基于上篇文章进行修改，黄色背景为修改的部分。 

1.介绍：Eureka集群就是n个Eureka服务器+n个Eureka客户端，目的是实现负载均衡，减轻单个服务器的压力。

2.原理：

3.代码实现 

• Eureka服务器(建立项目consultingPlatform_server):
  1).pom.xml

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.13.RELEASE</version>
    </parent>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
    </dependencies>

2） .application.properties （我们通过profiles指定不同的配置文件，模拟不同的服务器）|

 spring.profiles.active=server1
#spring.profiles.active=server2

.application-server1.properties

server.port=1001
#服务名称
spring.application.name=server
#eureka服务器路径
eureka.client.service-url.defaultZone=http://localhost:1002/eureka/

.application-server2.properties

server.port=1002
#服务名称
spring.application.name=server
#eureka服务器路径
eureka.client.service-url.defaultZone=http://localhost:1001/eureka/

在这里两台Eureka服务器互相注册。。ok,到这里Eureka集群服务器已经搭建完毕，通过修改profiles分别启动两个Eureka服务器。


3).Application.java(启动类)

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

 
@SpringBootApplication
@EnableEurekaServer
public class Application {
    public static void main(String[] args) {
        new SpringApplicationBuilder(Application.class).web(true).run(args);
    }
}

• 服务提供者（创建项目police_client）

1）.pom.xml

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.13.RELEASE</version>
    </parent>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
    </dependencies>

2） .application.properties（我们通过profiles指定不同的配置文件，模拟不同的客户端）

spring.profiles.active=client1

#spring.profiles.active=client2

.application-client1.properties

server.port=2001
#服务名称
spring.application.name=police
#eureka服务器路径
eureka.client.service-url.defaultZone=http://localhost:1001/eureka/,http://localhost:1002/eureka/

.application-client2.properties

server.port=2002
#服务名称
spring.application.name=police
#eureka服务器路径
eureka.client.service-url.defaultZone=http://localhost:1001/eureka/,http://localhost/eureka/

3 ).Application.java

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

/**
 * @author: lqh
 * @description:
 * @program: police_client
 * @create: 2018-06-06 11:50
 **/
@SpringBootApplication
@EnableEurekaClient
public class Application {
    public static void main(String[] args) {
        new SpringApplicationBuilder(Application.class).web(true).run(args);
    }
}

4 ). PoliceController.java

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

/**
 * @author: 
 * @description:
 * @program: police_client
 * @create: 2018-06-06 11:59
 **/
@RestController
public class PoliceController {
    @RequestMapping("call")
    public String call(HttpServletRequest request) {
        //这里返回url,便于查看服务提供者。
        return "call:" + request.getRequestURL().toString();
    }
}

• 服务调用者(创建项目people_caller)：

• 1).pom.xml
  

      <parent>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-parent</artifactId>
          <version>1.5.13.RELEASE</version>
      </parent>
      <dependencyManagement>
          <dependencies>
              <dependency>
                  <groupId>org.springframework.cloud</groupId>
                  <artifactId>spring-cloud-dependencies</artifactId>
                  <version>Edgware.SR3</version>
                  <type>pom</type>
                  <scope>import</scope>
              </dependency>
          </dependencies>
      </dependencyManagement>
      <dependencies>
          <dependency>
              <groupId>org.springframework.cloud</groupId>
              <artifactId>spring-cloud-starter-config</artifactId>
          </dependency>
          <dependency>
              <groupId>org.springframework.cloud</groupId>
              <artifactId>spring-cloud-starter-eureka</artifactId>
          </dependency>
          <dependency>
              <groupId>org.springframework.cloud</groupId>
              <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
          </dependency>
      </dependencies>

  2.application.properties
  

  server.port=6003
  
  #服务名称
  spring.application.name=people
  #注册路径
  eureka.client.service-url.defaultZone=http://localhost:6001/eureka/
  
  

  3.Application
  

  import org.springframework.boot.autoconfigure.SpringBootApplication;
  import org.springframework.boot.builder.SpringApplicationBuilder;
  import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
  
  @SpringBootApplication
  @EnableEurekaClient
  public class Application {
      public static void main(String[] args) {
          new SpringApplicationBuilder(Application.class).web(true).run(args);
      }
  }
  

  
  4.PeopleController
  

  import org.springframework.cloud.client.loadbalancer.LoadBalanced;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  import org.springframework.web.bind.annotation.RequestMapping;
  import org.springframework.web.bind.annotation.RestController;
  import org.springframework.web.client.RestTemplate;
  
   
  @Configuration
  @RestController
  public class PeopleController {
  
      @Bean
      @LoadBalanced
      RestTemplate getRestTemplate() {
          return new RestTemplate();
      }
  
      @RequestMapping("call")
      public String call() {
          return getRestTemplate().getForObject("http://police/call",String.class);
      }
  }

  
  OK,跑起来。。
  
  

• #图一：可以看到有2个服务器，2个服务提供者，1个服务调用者

• 
  
  

• #图二：可以看到有2个服务器，2个服务提供者，1个服务调用者

• #图三：服务调用者，可以看到端口一直在2001\2002之间切换，说明一直在调用不同的服务提供者。