SpringCloud 学习(2)：第一个eureka程序

灰太狼 2020-11-15 15:24 632阅读 0赞

#### 1.介绍：Eureka是一个服务管理器，其他业务组件（服务）通过rest注册到Eureka服务器，由服务器对服务进行监控，管理。 ####

#### 2.原理： ####

![20180606154219838][]

##### Eureka服务器：统一管理服务 #####

##### Eureka客户端（服务提供者）：将服务注册到Eureka服务器，获取注册列表 #####

##### Eureka客户端（服务调用者）：同样将服务注册到Eureka服务器，并且获取注册列表，再去调用具体的某个服务。 #####

如果还不理解，可以举个例子：

小明现在想报警，又不知道报警电话是多少，但是知道咨询平台，于是小明先向咨询平台咨询，知道了报警电话之后再去拨打报警电话。。在这里，我们可以把咨询平台当成Eureka服务器，警察局当成服务提供者，小明当成服务调用者。首先，警察局会先把报警电话提供给到咨询平台，当小明去咨询平台查询时会把警局电话给小明，小明再去拨打电话。

#### 3.第一个Eureka程序（下面我们模拟上面报警的例子，写一个Eureka程序） ####

*  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

server.port=6001
    
    #不把自己作为客户端注册
    eureka.client.register-with-eureka=false
    eureka.client.fetch-registry=false
    #eureka服务器路径
    eureka.client.service-url.defaultZone=http://localhost:${server.port}/eureka/

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

server.port=6002
    
    #服务名称
    spring.application.name=police
    #注册路径
    eureka.client.service-url.defaultZone=http://localhost:6001/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: lqh
     * @description:
     * @program: police_client
     * @create: 2018-06-06 11:59
     **/
    @RestController
    public class PoliceController {
        @RequestMapping("call")
        public String call(){
            return "call the police";
        }
    }

*  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。。  
      
    ![20180606165201750][]  
    ![20180606165215797][]

[20180606154219838]: /images/1605453862431.png
[20180606165201750]: /images/1605453839459.png
[20180606165215797]: /images/1605453816893.png