【SpringCloud】第二篇: 服务消费者（rest+ribbon）

前言:

必需学会SpringBoot基础知识

简介:

spring cloud 为开发人员提供了快速构建分布式系统的一些工具，包括配置管理、服务发现、断路器、路由、微代理、事件总线、全局锁、决策竞选、分布式会话等等。它运行环境简单，可以在开发人员的电脑上跑。

工具:

JDK8

apache-maven-3.5.2

IntelliJ IDEA 2017.3 x64

ribbon 简介

Ribbon is a client side load balancer which gives you a lot of control over the behaviour of HTTP and TCP clients. Feign already uses Ribbon, so if you are using @FeignClient then this section also applies. —–摘自官网

ribbon是一个负载均衡客户端，可以很好的控制htt和tcp的一些行为。Feign默认集成了ribbon。

一、准备工作

本篇是基于第一篇为基础, 首先, 启动 eureka-server:8761 和 eureka-client 项目的dev:8762, pro:8763 分别启动两个实例. 临时搭建一个小集群, 然后访问 127.0.0.1:8761 查看 eureka-client 两个实例是否启动了.

二、新建服务消费者 (eureka-ribbon)

2.1 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">
	<modelVersion>4.0.0</modelVersion>

	<groupId>com.lwc</groupId>
	<artifactId>eureka-ribbon</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>eureka-ribbon</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.10.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>Edgware.SR2</spring-cloud.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-eureka-server</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-ribbon</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>

2.2  通过 application.yml 跳转 application-dev.yml 配置程序名, 端口 和指定注册中心 如下:

spring:
  application:
      name: eureka-ribbon
  profiles:
    active: ${@profileActiv@:dev}

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
server:
  port: 8764

2.3  通过@EnableDiscoveryClient向服务中心注册, 并且利用ioc注入@Bean, 然后通过@LoadBalanced表明restTemplate()开启负载均衡功能; 如下:

package com.lwc;

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

/**
 * @author Eddie
 */
@EnableDiscoveryClient
@SpringBootApplication
public class EurekaRibbonApplication {

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

package com.lwc.template;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;

/**
 * @author eddie.lee
 * @Package com.lwc.template
 * @ClassName RestConfig
 * @description
 * @date created in 2018-03-26 19:54
 * @modified by
 */
@Component
public class RestConfig {

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

}

2.4 创建服务层测试使用, ribbonService() 里面url使用了eureka-client服务器名称代替127.0.0.1:8762; 如下:

package com.lwc.service;

/**
 * @author eddie.lee
 * @Package com.lwc.service
 * @ClassName RibbonService
 * @description
 * @date created in 2018-03-26 19:55
 * @modified by
 */
public interface RibbonService {

    String ribbonService(String name);

}

package com.lwc.service.impl;

import com.lwc.service.RibbonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

/**
 * @author eddie.lee
 * @Package com.lwc.service.impl
 * @ClassName RibbonServiceImpl
 * @description
 * @date created in 2018-03-26 19:57
 * @modified by
 */
@Service
public class RibbonServiceImpl implements RibbonService {

    @Autowired
    private RestTemplate restTemplate;

    @Override
    public String ribbonService(String name) {
        final String url = "http://eureka-client/eureka/client?name=" + name;
        return restTemplate.getForObject(url, String.class);
    }

}

2.5 创建 controller 作为调用测试服务层使用; 如下:

package com.lwc.controller;

import com.lwc.service.RibbonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author eddie.lee
 * @Package com.lwc.controller
 * @ClassName RibbonControler
 * @description 服务消费者
 * @date created in 2018-03-26 20:02
 * @modified by
 */
@RestController
@RequestMapping("/eureka")
public class RibbonControler {

    @Autowired
    private RibbonService ribbonService;

    @GetMapping("/ribbon")
    public String Ribbon(@RequestParam String name) {
        return ribbonService.ribbonService(name);
    }

}

新手解析: ribbon相当于 请求ribbon的时候会随机访问eureka-client:8762 和 eureka-client:8763,

为什么? 如果一台eureka-client:8762挂了, 还有eureka-client:8763, 保证服务正常使用;

eureka-ribbon
http://localhost:8764/eureka/ribbon?name=eddie

标签

2-1

源码下载
https://github.com/eddie-code/SpringCloudDemo#springclouddemo