穿越JavaSpringCloud篇第一章负载均衡Ribbon|第2节RestTemplate+NACOS+Ribbon实现服务的注册与发现和负载均衡。

开发环境

基于&＃xff1a;IntelliJ IDEA、Maven构建工具、JDK1.8、SpringBoot 2.3.4 、Spring4.3.28编写。

官人如需使用 IDEA 请阅读教程&＃xff1a;IntelliJ IDEA
官人如需使用 Maven 请阅读教程&＃xff1a;Maven 构建工具的下载与安装

更多干货

请参考&＃xff1a;《穿越 Java 之 语法基础篇》 系列文章
请参考&＃xff1a;《穿越 Java 之 Web基础篇 》系列文章
请参考&＃xff1a;《穿越 Java 之 开发必备框架篇 》 系列文章
请阅读&＃xff1a;《穿越 Java 之 SpringBoot》系列文章
请阅读&＃xff1a;《穿越 Java 之 SpringCloud》 系列文章

需求

实现 user 服务 对 order 服务进行调用。使用RestTemplate&＃43; NACOS&＃43;Ribbon 实现服务的注册与发现和负载均衡。

分析

• 在springcloud 要考虑的是&＃xff1a;user要想调用order 必须要知道 它的一个IP 端口 路径进行调用.

• 但是存在一个问题就是 假如还有其他的模块 就会再维护一份url地址 &＃xff0c;干很多重复的工作。如下图&＃xff1a;

• 所以在微服务的场景下我们要先去考虑服务的注册与发现&＃xff0c;如下图&＃xff1a;
  

• 接下来就是选择 NACOS 进行服务的注册&＃xff0c;可参考NACOS服务注册

• 然后选择Ribbon 提供的功能是&＃xff1a;【服务发现&＃43;负载均衡】

需要用到&＃xff1a;OpenFeign组件
GitHupz网址&＃xff1a;https://github.com/OpenFeign/feign

使用

User-service

目录结构

pom.xml 依赖

• 整合springcloud–>spring-cloud-dependencies
• 整合spring cloud alibaba–>spring-cloud-alibaba-dependencies
• 整合spring cloud netflix–>spring-cloud-netflix-dependencies
• 整合ribbon --> spring-cloud-starter-netflix-ribbon

<parent><groupId>org.springframework.bootgroupId><artifactId>spring-boot-starter-parentartifactId><version>2.3.4.RELEASEversion><relativePath/> parent><groupId>com.examplegroupId><artifactId>user-serviceartifactId><version>0.0.1-SNAPSHOTversion><name>user-servicename><description>Demo project for Spring Bootdescription><properties><java.version>1.8java.version>properties><dependencies><dependency><groupId>org.springframework.bootgroupId><artifactId>spring-boot-starter-webartifactId>dependency><dependency><groupId>org.projectlombokgroupId><artifactId>lombokartifactId><optional>trueoptional>dependency><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-starter-netflix-ribbonartifactId>dependency><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-starter-alibaba-nacos-discoveryartifactId>dependency>dependencies>
<dependencyManagement><dependencies><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-dependenciesartifactId><version>Greenwich.SR3version><type>pomtype><scope>importscope>dependency><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-alibaba-dependenciesartifactId><version>0.9.0.RELEASEversion><type>pomtype><scope>importscope>dependency><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-netflix-dependenciesartifactId><version>2.1.3.RELEASEversion><type>pomtype><scope>importscope>dependency>dependencies>dependencyManagement>


application.yml配置文件


server:port: 8096
#告诉我们的项目 nacos的地址是什么&＃xff0c;方便注册localhost:8848
spring:cloud:nacos:discovery:server-addr: localhost:8848application:name: order-service

编写HelloController 类

• &＃64;Slf4j --> 日志的输出
• RestTemplate -->可以访问远程Http服务

package com.example.userservice.controller;import lombok.extern.slf4j.Slf4j;
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.RestController;
import org.springframework.web.client.RestTemplate;import java.util.List;import java.util.concurrent.ThreadLocalRandom;
import java.util.stream.Collectors;&＃64;RestController
&＃64;Slf4j
public class HelloController {&＃64;GetMapping("/hello")public String hello(){return "Hello Spring Cloud";}&＃64;Autowiredprivate RestTemplate restTemplate;&＃64;GetMapping("/test2")public String test2(){//Ribbon会根据order-service名称做服务发现和负载均衡-->url192.168.0.3:return this.restTemplate.getForObject("http://order-service/order/query",String.class);}
}


编写UserServiceApplication 启动类

• 注册了一个Bean -->RestTemplate

package com.example.userservice;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
&＃64;SpringBootApplication
public class UserServiceApplication {public static void main(String[] args) {SpringApplication.run(UserServiceApplication.class, args);}&＃64;Bean&＃64;LoadBalanced//此注解相当于为restTemplate整合了Ribbon的功能public RestTemplate restTemplate(){return new RestTemplate();}
}


Order-service

目录结构

pom.xml 依赖

<parent><groupId>org.springframework.bootgroupId><artifactId>spring-boot-starter-parentartifactId><version>2.3.4.RELEASEversion><relativePath/> parent><groupId>com.examplegroupId><artifactId>user-serviceartifactId><version>0.0.1-SNAPSHOTversion><name>user-servicename><description>Demo project for Spring Bootdescription><properties><java.version>1.8java.version>properties><dependencies><dependency><groupId>org.springframework.bootgroupId><artifactId>spring-boot-starter-webartifactId>dependency><dependency><groupId>org.projectlombokgroupId><artifactId>lombokartifactId><optional>trueoptional>dependency><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-starter-alibaba-nacos-discoveryartifactId>dependency>dependencies>
<dependencyManagement><dependencies><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-dependenciesartifactId><version>Greenwich.SR3version><type>pomtype><scope>importscope>dependency><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-alibaba-dependenciesartifactId><version>0.9.0.RELEASEversion><type>pomtype><scope>importscope>dependency><dependency><groupId>org.springframework.cloudgroupId><artifactId>spring-cloud-netflix-dependenciesartifactId><version>2.1.3.RELEASEversion><type>pomtype><scope>importscope>dependency>dependencies>dependencyManagement>


application.yml配置文件

server:port: 8096
#告诉我们的项目 nacos的地址是什么&＃xff0c;方便注册localhost:8848
spring:cloud:nacos:discovery:server-addr: localhost:8848application:name: order-service


编写HelloController 类

package com.example.orderservice.controller;import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
&＃64;RestController
&＃64;RequestMapping(path &＃61; {"/order"},method &＃61; {RequestMethod.GET})
&＃64;Slf4j
public class DemoController {&＃64;GetMapping("/query")public String demo(){log.info("我被访问了&＃xff01;");return "已查询出数据";}
}


编写UserServiceApplication 启动类

package com.example.orderservice;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;&＃64;SpringBootApplication
public class OrderServiceApplication {public static void main(String[] args) {SpringApplication.run(OrderServiceApplication.class, args);}
}


测试

• 首先开启通过不同端口三个order服务1个user服务&＃xff0c;以我的为例开启了8094,95,96的order服务和一个8090的用户服务。
  
• 访问&＃xff1a;http://192.168.148.1:8848/nacos/
• 进入nacos界面可以看到注册进去的服务。
  
• 最后访问http://localhost:8090/test2测试调用
  
• 每个端口访问的次数不同