SpringCloud- 注册服务中心（Eureka）

1.SpirngCloud

微服务架构（属于分布式架构）是在传统的soa架构上升级，将业务逻辑拆分的更细，轻量级，在开发过程中例如电商项目中:

支付服务    订单服务    会员服务 （可以理解一个服务就是一个业务逻辑 一般一个服务连接单独的数据库，这些都是接口项目）

不同的工程 可能都需要调用到支付服务，或者订单服务 通过RPC远程调用接口：http+json+restful,这些接口只能在内部访问，即使和外网接口进行对接也是采用https

一个公司项目有很多接口，每个接口有自己的地址，对这些接口如何能快速系统的管理。这就是springcloud能做的事情

 

2.搭建SpirngCloud-Eureka例子：

Eureka是Netflix开源的一个RESTful服务，主要用于服务的注册发现。Eureka由两个组件组成：Eureka服务器和Eureka客户端。Eureka服务器用作服务注册服务器。Eureka客户端是一个java客户端，用来简化与服务器的交互、作为轮询负载均衡器，并提供服务的故障切换支持。Netflix在其生产环境中使用的是另外的客户端，它提供基于流量、资源利用率以及出错状态的加权负载均衡。

本次实现的例子:订单服务调用会员服务

 

 步骤一 （引入所需要的依赖）：

<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.jiahou</groupId>
    <artifactId>eureka-service</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.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>
    </properties>
    <dependencies>
        <!--eureka server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
        <!-- spring boot test -->
        <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>Dalston.RC1</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>
    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>


</project>

步骤二（创建.yml文件或者.properties文件）：

server:
  port: 8888
eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

步骤三(创建启动类)：

package com;

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

@SpringBootApplication
@EnableEurekaServer
public class EurekaApp {

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

}

 

步骤四(运行结果)：输入127.0.0.1:8888

 

 

3.搭建接口提供服务：

步骤一：

创建member-server项目(pom导入所需要的依赖):

<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.jiahou</groupId>
    <artifactId>member-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.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>
    </properties>
    <dependencies>
        <!--eureka server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
        <!-- spring boot test -->
        <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>Dalston.RC1</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>
    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>


</project>

步骤二：

创建yml配置文件

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8888/eureka/ //注册中心的地址
server:
  port: 8762 //项目member-server的端口
spring:
  application:
    name: service-member //在注册服务中心的名字

 

步骤三：

 

package com.entity;

public class User {
    private String userName;
    private String userAge;

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserAge() {
        return userAge;
    }

    public void setUserAge(String userAge) {
        this.userAge = userAge;
    }

}

 

package com.controller;

import java.util.ArrayList;
import java.util.List;

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

import com.entity.User;

@RestController
public class ReqController {
    @RequestMapping("/getMenberMsg")
    public List<User> getMemberMsg() {
        List<User> arrs = new ArrayList<>();
        User user = new User();
        user.setUserAge("15");
        user.setUserName("Jason");
        arrs.add(user);
        return arrs;
    }

}

 

 

package com;

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

@SpringBootApplication
@EnableEurekaServer//该注解的作用是将此服务注册到eureka服务中心
public class MemberApp {

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

}

 

步骤四：

启动member-server服务

 

请求地址栏输入地址：http://127.0.0.1:8762/getMenberMsg

（启动member-server服务的时候 需要先把eureka服务器启动好，否则member-server日志窗口会打印找不到注册服务的异常！但是并不妨碍 member-server的运行）

 

 步骤五：

 打开eureka-server服务,可以看到member-server已经注册到eureka注册服务中心

 

 

4.搭建消费接口服务：

步骤一:（创建order-server服务）

pom文件导入所需要的依赖：

<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.jiahou</groupId>
    <artifactId>order-server</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.2.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>
    </properties>
    <dependencies>
        <!--eureka server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
        <!-- spring boot test -->
        <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>Dalston.RC1</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>
    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>


</project>

 

步骤二：（创建yml文件）

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8888/eureka/
server:
  port: 8764
spring:
  application:
    name: service-order

 

 

步骤三：远程调用member-server

远程调用的方法有三种：

1.Rest

2.Feign

3.ribbon(用作负载均衡)

使用RestTemplate 远程调用接口

 

package com.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

@Service
public class MemberService {
    @Autowired
    RestTemplate restTemplate;

    @SuppressWarnings("unchecked")
    public List<Object> getOrderByUserList() {
        //"http://service-member/getMenberMsg" 这个地址对应
        return restTemplate.getForObject("http://service-member/getMenberMsg", List.class);
    }
}

 

控制层调用service层

package com.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.service.MemberService;

@RestController
public class OrderController {

    @Autowired
    private MemberService memberService;

    @RequestMapping("/getOrderByUserList")
    public List<Object> getOrderByUserList() {
        return memberService.getOrderByUserList();
    }

}

 

 步骤四：(启动order-server)

 启动之前需要配置RestTemplate 模板

 

package com;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaServer
public class OrderApp {

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

    @Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

 

打开eureka服务中心：

 

 

 步骤五：(测试远程调用)

 

 

 

5.Eureka注册服务中心调用原理：

 

 

 （1）会员服务（member-server）注册到eureka服务中心的时候 将会员服务的ip地址和端口信息 都存放到了服务中心 

 server port:=8762

spring.application.name:=service-member

 

（2） 订单服务可以通过service-member在注册中心找到service-member对应的真是ip地址

 

（3） 订单服务 通过httpclient 调用会员服务