《SpringCloud微服务实战》学习笔记之服务治理Eureka(单节点)

Euraka是NetFlix微服务套件中的一部分，它基于Netflix Eureka做了二次封装，主要负责完成微服务架构中的服务治理和服务发现功能。

示例：

一、Eureka搭建服务注册
1、创建maven项目SpringCloud-EurekaServer

2、修改pom.xml文件，pom中添加Euraka依赖jar包。

<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">  <modelVersion>4.0.0</modelVersion>  <groupId>com.spring</groupId>  <artifactId>SpringCloud-EurekaServer</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>SpringCloud-EurekaServer</name>  <url>http://maven.apache.org</url>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <java.version>1.8</java.version>  </properties>    <parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>1.3.5.RELEASE</version>        <relativePath/> <!-- lookup parent from repository -->    </parent>    <dependencies>        <dependency>            <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-test</artifactId>        <scope>test</scope>        </dependency>        <dependency>            <groupId>org.springframework.cloud</groupId>        <artifactId>spring-cloud-starter-eureka-server</artifactId>        </dependency>    </dependencies>    <dependencyManagement>        <dependencies>            <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-dependencies</artifactId>            <version>Brixton.RELEASE</version>            <type>pom</type>            <scope>import</scope>        </dependency>        </dependencies>    </dependencyManagement>    <build>        <plugins>            <plugin>                <groupId>org.springframework.boot</groupId>                <artifactId>spring-boot-maven-plugin</artifactId>            </plugin>        </plugins>    </build></project>

3、创建application.propertises文件

server.port=8888eureka.client.register-with-eureka=falseeureka.client.fetch-registry=falseeureka.client.serviceUrl.defaultZone=http://localhost:${server.port}/eureka/

• server.port：Eureka服务注册端口。
• eureka.client.register-with-eureka：设置为false，代表不向注册中心注册自己。

• eureka.client.fetch-registry：设置为false，代表不去检索服务。

  通过http://localhost:8888/访问注册中心：
  

  由于该注册中心还没注册任何服务，所以Instances currently registered with Eureka栏为“No instances available”。

二、在服务注册中心注册helloService服务

1、创建Maven项目SpringCloud-Service

2、修改pom.xml，添加Euraka和SpringBoot依赖

<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">  <modelVersion>4.0.0</modelVersion>  <groupId>com.spring</groupId>  <artifactId>SpringCloud-Service</artifactId>  <version>0.0.1-SNAPSHOT</version>  <packaging>jar</packaging>  <name>SpringCloud-Service</name>  <url>http://maven.apache.org</url>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>    <java.version>1.8</java.version>  </properties>    <parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>1.3.5.RELEASE</version>        <relativePath/> <!-- lookup parent from repository -->    </parent>    <dependencies>        <dependency>            <groupId>org.springframework.boot</groupId>            <artifactId>spring-boot-starter-web</artifactId>        </dependency>        <dependency>            <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-test</artifactId>        <scope>test</scope>        </dependency>        <dependency>            <groupId>org.springframework.cloud</groupId>        <artifactId>spring-cloud-starter-eureka-server</artifactId>        </dependency>    </dependencies>    <dependencyManagement>        <dependencies>            <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-dependencies</artifactId>            <version>Brixton.RELEASE</version>            <type>pom</type>            <scope>import</scope>        </dependency>        </dependencies>    </dependencyManagement></project>

3、新增application.propertises文件

server.port=9999spring.application.name=helloServiceeureka.client.serviceUrl.defaultZone=http://localhost:8888/eureka/

• server.port：helloService服务端口。
• spring.application.name：向服务注册中心注册的服务名。
• eureka.client.serviceUrl.defaultZone：eureka服务注册中心Url。

4、实现HelloServiceController

package com.spring.springcloud.rest;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.cloud.client.ServiceInstance;import org.springframework.cloud.client.discovery.DiscoveryClient;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class HelloServiceController {    @Autowired    private DiscoveryClient client;    @RequestMapping(value="/hello",method=RequestMethod.GET)    public String greeting(){        ServiceInstance si = client.getLocalServiceInstance();        return "hello";    }}

5、最后向Application主类中添加注解@EnableDiscoveryClient，用于激活Eureka中的EnableDiscoveryClient实现。

package com.spring.springcloud;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.client.discovery.EnableDiscoveryClient;@EnableDiscoveryClient@SpringBootApplicationpublic class Application {    public static void main(String[] args) {        SpringApplication.run(Application.class, args);    }}

运行HelloService注册服务，启动成功之后，访问注册中心：http://localhost:8888/

此时我们看见helloService已经成功注册。