springcloud(第三篇)springcloud eureka 服务注册与发现 *****

http://blog.csdn.net/liaokailin/article/details/51314001

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spring cloud eureka

eureka 用以服务发现、服务注册，比较流行的有consul

简介

eureka为netflix开源软件，分为三个部分：

• eureka服务:用以提供服务注册、发现，已一个war的形式提供 http://search.maven.org/#search%7Cga%7C1%7Ceureka-server
  或者编译源码，将war拷贝进tomcat即可提供服务

• eureka-server: 相对client端的服务端，为客户端提供服务，通常情况下为一个
  集群

• eureka-client:客户端，通过向eureka服务发现注册的可用的eureka-server，向后端发送请求

spring cloud eureka

spring cloud eureka 分为两部分

• @EnableEurekaClient: 该注解表明应用既作为eureka实例又为eureka client 可以发现注册的服务
• @EnableEurekaServer: 该注解表明应用为eureka服务，有可以联合多个服务作为集群，对外提供服务注册以及发现功能

client 端

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">    <parent>        <artifactId>springcloud</artifactId>        <groupId>com.lkl.springcloud</groupId>        <version>1.0-SNAPSHOT</version>    </parent>    <modelVersion>4.0.0</modelVersion>    <artifactId>eureka</artifactId>    <dependencyManagement>        <dependencies>            <dependency>                <groupId>org.springframework.cloud</groupId>                <artifactId>spring-cloud-netflix</artifactId>                <version>1.0.7.RELEASE</version>                <type>pom</type>                <scope>import</scope>            </dependency>        </dependencies>    </dependencyManagement>    <dependencies>        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-eureka</artifactId>        </dependency>        <!--表示为web工程-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <!--暴露各种指标-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-actuator</artifactId>        </dependency>    </dependencies></project>
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启动应用 Application.Java

package com.lkl.springcloud.eureka;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.builder.SpringApplicationBuilder;import org.springframework.cloud.netflix.eureka.EnableEurekaClient;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.Configuration;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;/** * Created by liaokailin on 16/4/30. */@SpringBootApplication@EnableEurekaClient@RestController@EnableAutoConfigurationpublic class Application {    @RequestMapping("/")    public String home() {        return "Hello world";    }    public static void main(String[] args) {        new SpringApplicationBuilder(Application.class).web(true).run(args);    }}
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创建配置application.properties

server.port=9090spring.application.name=eureka.client#eureka.client.serviceUrl.defaultZone=http://120.76.145.187:8080/eureka-server-1.4.6/v2/eureka.client.serviceUrl.defaultZone=http://localhost:7070/eureka/eureka.instance.appname=eureka.client.01#eureka.client.registerWithEureka=true#eureka.client.fetchRegistry=true
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eureka.client.serviceUrl.defaultZone 配置eureka服务地址

server

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 http://maven.apache.org/xsd/maven-4.0.0.xsd">    <parent>        <artifactId>springcloud</artifactId>        <groupId>com.lkl.springcloud</groupId>        <version>1.0-SNAPSHOT</version>    </parent>    <modelVersion>4.0.0</modelVersion>    <artifactId>eureka-server</artifactId>    <dependencyManagement>        <dependencies>            <dependency>                <groupId>org.springframework.cloud</groupId>                <artifactId>spring-cloud-netflix</artifactId>                <version>1.0.7.RELEASE</version>                <type>pom</type>                <scope>import</scope>            </dependency>        </dependencies>    </dependencyManagement>    <dependencies>        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-eureka</artifactId>        </dependency>        <!--表示为web工程-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <!--暴露各种指标-->        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-actuator</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-eureka-server</artifactId>        </dependency>    </dependencies></project>
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启动应用Application.java

package com.lkl.springcloud.eureka;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.builder.SpringApplicationBuilder;import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;/** * Created by liaokailin on 16/4/30. */@EnableEurekaServer@SpringBootApplicationpublic class Application {    public static void main(String[] args) {        new SpringApplicationBuilder(Application.class).web(true).run(args);    }}
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配置application.yml

server:  port: 7070spring:  application:    name: server-01eureka:  client:    serviceUrl:      defaultZone: http://localhost:7070/eureka/  instance:    metadataMap:      instanceId: ${spring.application.name}:${spring.application.instance_id:${random.value}}
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spring.application.name表示应用名称，集群名称需要一致
defaultZone表示向自身注册，例子中有三个server节点构成集群，其余两个两个节点也向该端口注册
instanceId 表示eureka instance 标识，需要唯一，如果不配置，多个节点最终只会有一个生效

同样的配置第二个节点,第三个节点

启动所有服务端应用
访问 http://localhost:7070 可以查看eureka注册服务信息

访问 http://localhost:7070/eureka/apps 可以查看metadata

服务发现

在客户端创建Component

DiscoveryService.java

package com.lkl.springcloud.eureka;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.CommandLineRunner;import org.springframework.cloud.client.ServiceInstance;import org.springframework.cloud.client.discovery.DiscoveryClient;import org.springframework.stereotype.Component;import org.springframework.util.CollectionUtils;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import java.util.List;/** * Created by liaokailin on 16/4/30. */@Component@RestControllerpublic class DiscoveryService {    @Autowired    private DiscoveryClient discoveryClient;    @RequestMapping("/discovery")    public String doDiscoveryService(){        StringBuilder buf = new StringBuilder();        List<String> serviceIds = discoveryClient.getServices();        if(!CollectionUtils.isEmpty(serviceIds)){            for(String s : serviceIds){                System.out.println("serviceId:" + s);                List<ServiceInstance> serviceInstances =  discoveryClient.getInstances(s);                if(!CollectionUtils.isEmpty(serviceInstances)){                    for(ServiceInstance si:serviceInstances){                        buf.append("["+si.getServiceId() +" host=" +si.getHost()+" port="+si.getPort()+" uri="+si.getUri()+"]");                    }                }else{                    buf.append("no service.");                }            }        }        return buf.toString();    }}
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访问 http://localhost:9090/discovery 实现服务发现。

ok ~ it’s work ! more about is here

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