在微服务架构中,业务都会被拆分成一个独立的服务,服务与服务的通讯是基于http restful的。Spring cloud有两种服务调用方式,一种是ribbon+restTemplate,另一种是feign。在这一篇文章首先讲解下基于ribbon+rest。
一、准备工作
这一篇文章基于上一篇文章的工程,启动eureka-server 工程;启动service-client工程,它的端口为9060;将service-client的配置文件的端口改为9061,并启动,这时你会发现:service-client在eureka-server注册了2个实例,这就相当于一个小的集群。
二、建一个服务消费者
重新新建一个spring-boot工程,取名为:service-ribbon;
在它的pom.xml继承了父pom文件,并引入了以下依赖:
<?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.zhihua</groupId>
<artifactId>service-ribbon</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>service-ribbon</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>com.zhihua</groupId>
<artifactId>spring_cloud_pro</artifactId>
<version>0.0.1-SNAPSHOT</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>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<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>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
配置文件application.yml如下:
eureka:
client:
serviceUrl:
defaultZone: http://user:password123@localhost:8761/eureka/
server:
port: 9062
spring:
application:
name: service-ribbon
在工程的启动类中,通过@EnableDiscoveryClient向服务中心注册;并且向程序的ioc注入一个bean: restTemplate;并通过@LoadBalanced注解表明这个restRemplate开启负载均衡的功能。
@SpringBootApplication
@EnableEurekaClient
public class ServiceRibbonApplication {
public static void main(String[] args) {
SpringApplication.run(ServiceRibbonApplication.class, args);
}
@Bean
@LoadBalanced
RestTemplate restTemplate() {
return new RestTemplate();
}
}
写一个测试类RibbonController,通过之前注入ioc容器的restTemplate来消费eureka-client服务的“/simple/{id}”接口,在这里我们直接用的程序名替代了具体的url地址,在ribbon中它会根据服务名来选择具体的服务实例,根据服务实例在请求的时候会用具体的url替换掉服务名;test接口用于检测是否进行负载代码如下:
package com.zhihua.serviceribbon.controller;
import com.zhihua.serviceribbon.entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
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;
@RestController
public class RibbonController {
@Autowired
private RestTemplate restTemplate;
@Autowired
private LoadBalancerClient loadBalancerClient;
@GetMapping("/simple/{id}")
public User hello(@PathVariable Long id){
return restTemplate.getForObject("http://eureka-client/simple/"+id,User.class);
}
@GetMapping("/test")
public String test() {//localhost:eureka-provider2:9072 ,
ServiceInstance serviceInstance = this.loadBalancerClient.choose("eureka-client");
System.out.println("111" + ":" + serviceInstance.getServiceId() + ":" + serviceInstance.getHost() + ":" + serviceInstance.getPort());
//ServiceInstance serviceInstance2 = this.loadBalancerClient.choose("eureka-client2");
//System.out.println("222" + ":" + serviceInstance2.getServiceId() + ":" + serviceInstance2.getHost() + ":" + serviceInstance2.getPort());
return "1";
}
}
访问http://localhost:9062/simple/1 完成服务间的调用
使用test接口测试负载情况: 在启动一个eureka-client端口号:9063,访问http://localhost:9062/test 查看控制台情况如下:
发现轮询调用,实现负载
使用配置文件修改轮询策略
添加配置
eureka-client: #此处是指定服务名称
ribbon:
NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule #随机
完成随机轮询