Eureka服务发现

服务发现组件单独拿出来

服务发现组件有consul、zookeeper、eureka等，下面列出优缺点

eureka官方架构图

application service 服务提供者

application client 服务消费者

eureka组件有：eureka server和eureka client 

eureka server项目结构如下图：

pom.xml

<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.cookqq</groupId>
  <artifactId>euraka</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>
  
  <!-- 引入spring boot的依赖 -->
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.9.RELEASE</version>
  </parent>
  

  <name>euraka</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
   <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
  
   <!-- 引入spring cloud的依赖 -->
  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>Edgware.RELEASE</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
  </dependencyManagement>
</project>

application.yml

server:
  port: 8761                    # 指定该Eureka实例的端口
eureka:
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

启动类

package com.cookqq.euraka;

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

/**
 * 
 *eureka注册中心
 */
@SpringBootApplication
@EnableEurekaServer
public class EurakaApp 
{
    public static void main( String[] args )
    {
        SpringApplication.run(EurakaApp.class, args);
    }
}

启动类，访问浏览器http://localhost:8761/

eureka client集成过程

provider-user/consumer-order配置eureka client

pom.xml增加依赖

<dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>

application.yml增加

spring:
  application:
    name: provider-user
...    
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
  instance:
    prefer-ip-address: true

改变订单控制层代码OrderController.java

package com.cookqq.consumer.controller;

import java.util.List;
import java.util.Random;

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.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.cookqq.consumer.bean.User;

@RestController
public class OrderController {

	@Autowired
	private RestTemplate restTemplate;
	
	@Autowired
	private DiscoveryClient discoveryClient;
	
	@GetMapping("/user/{id}")
	public User findUserById(@PathVariable Long id){
//		return this.restTemplate.getForObject("http://127.0.0.1:8000/"+id, User.class);
		List<ServiceInstance> listInfo = discoveryClient.getInstances("provider-user");
		if(listInfo.size()>0){
			return this.restTemplate.getForObject(
					listInfo.get(new Random().nextInt(listInfo.size())).getUri()+"/"+id, 
					User.class);
		}
		return null;
	}
}

启动所有项目，访问浏览器