spring cloud（服务注册中心及服务提供者——初学一）

Eureka是Netflix开源的一款提供服务注册和发现的产品，它提供了完整的Service Registry和Service Discovery实现。也是springcloud体系中最重要最核心的组件之一。

Eureka的基本架构：

1、Eureka Server

• 提供服务注册和发现

2、Service Provider

• 服务提供方
• 将自身服务注册到Eureka，从而使服务消费方能够找到

3、Service Consumer

• 服务消费方
• 从Eureka获取注册服务列表，从而能够消费服务

一、创建服务注册中心

　　1、创建spring boot项目（利用idea的Spring Initializr快速创建项目）

　　2、引入eureka-server依赖（也可以在创建项目时勾选eureka-server服务，自动生成依赖） 注意版本号,版本不对可能启动会报错，本次使用Dalston.SR1版本

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.daqsoft</groupId>
    <artifactId>cloud_demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>cloud_demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Dalston.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <!--添加依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </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>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

　　3、启动类中开启服务注册中心功能

package com.daqsoft;

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

@SpringBootApplication
//开启服务注册中心
@EnableEurekaServer
public class CloudDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(CloudDemoApplication.class, args);
    }
}

　　4、在默认设置下，该服务注册中心也会将自己作为客户端来尝试注册它自己，所以我们需要禁用它的客户端注册行为，只需要在application.properties中问增加如下配置：

server.port=1111

#是否将自己注册到Eureka Server，默认为TRUE
eureka.client.register-with-eureka=false
#是否从Eureka Server获取注册信息，默认为TRUE
eureka.client.fetch-registry=false
#设置与Eureka Server的交互地址,查询服务和注册服务都需要依赖这个地址
eureka.client.serviceUrl.defaultZone=http://localhost:${server.port}/eureka/

　　5、浏览器访问 　　localhost:1111  （此时没有任务服务注册）

　　

二、创建服务提供方

　　1、创建spring boot项目如上

　　2、添加eureka依赖

<?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">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.daqsoft</groupId>
    <artifactId>server_demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>server_demo</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
        <spring-cloud.version>Dalston.SR1</spring-cloud.version>
    </properties>

    <dependencies>
        <!--添加依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </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>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

　　3、启动类中添加注解，激活DiscoveryClient

package com.daqsoft;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
//激活DiscoveryClient的使用
@EnableDiscoveryClient
public class ServerDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(ServerDemoApplication.class, args);
    }
}

　　4、创建controller提供简单的添加任务

package com.daqsoft;

import org.apache.log4j.Logger;
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.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @Description Created by liaoxx on 2017-6-12.
 */
@RestController
public class ComputerController {
    private final Logger logger = Logger.getLogger(getClass());

    @Autowired
    private DiscoveryClient client;

    @RequestMapping(value = "/add",method = RequestMethod.GET)
    public Integer add(@RequestParam Integer a, @RequestParam Integer b) {
        ServiceInstance instance = client.getLocalServiceInstance();
        Integer c = a + b;
        logger.info("/add , post:"+instance.getPort()+" service_id:"+instance.getServiceId()+" result:"+c);
        return c;
    }
}

　　5、修改配置文件如下

#指定微服务的名称后续在调用的时候只需要使用该名称就可以进行服务的访问
spring.application.name=compute-service
#方便测试，设置为不同的端口
server.port=2222
#对应服务注册中心的配置内容，指定服务注册中心的位置
eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka/

　　　6、启动服务，再次访问　　localhost:1111