spring cloud 入门实践系列

Ribbon is a client side IPC library that is battle-tested in cloud. It provides the following features
Load balancing
Fault tolerance
Multiple protocol (HTTP, TCP, UDP) support in an asynchronous and reactive model
Caching and batching

创建ribbon测试项目

项目结构如图

pom文件

<?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.zhang</groupId>    <artifactId>ribbontest</artifactId>    <version>0.0.1-SNAPSHOT</version>    <packaging>jar</packaging>    <name>ribbontest</name>    <description>Demo project for Spring Boot</description>    <parent>        <groupId>org.springframework.boot</groupId>        <artifactId>spring-boot-starter-parent</artifactId>        <version>1.5.4.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>Dalston.SR1</spring-cloud.version>    </properties>    <dependencies>        <dependency>            <groupId>org.springframework.cloud</groupId>            <artifactId>spring-cloud-starter-ribbon</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-web</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>

属性配置文件application.properties

server.port=7071代表RibbontestApplication暴露在7071端口

spring.application.name=ribbonserver.port=7071eureka.client.serviceUrl.defaultZone=http://localhost:8761/eureka/servicehello.ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RandomRule

暴露服务调用接口

package com.zhang.web;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;import org.springframework.web.client.RestTemplate;/** * Created by zhangxiaolong on 17/7/20. */@RestControllerpublic class ConsumerClass {    @Autowired    private RestTemplate restTemplate;    @Autowired    private LoadBalancerClient loadBalancerClient;    @RequestMapping(value = "/hello", method = RequestMethod.GET)    public String hello(@RequestParam String name) {        this.loadBalancerClient.choose("service-hello");//随机访问策略        return restTemplate.getForEntity("http://service-hello/hello?name="+name, String.class).getBody();    }}

应用程序运行入口

package com.zhang;import com.netflix.loadbalancer.IRule;import com.netflix.loadbalancer.RandomRule;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.client.loadbalancer.LoadBalanced;import org.springframework.cloud.netflix.eureka.EnableEurekaClient;import org.springframework.context.annotation.Bean;import org.springframework.web.client.RestTemplate;@EnableEurekaClient@SpringBootApplicationpublic class RibbontestApplication {    @Bean    @LoadBalanced    RestTemplate restTemplate() {        return new RestTemplate();    }    @Bean    public IRule ribbonRule() {        return new RandomRule();    }    public static void main(String[] args) {        SpringApplication.run(RibbontestApplication.class, args);    }}

创建service-hello服务

使用eureka作为注册中心，暴露在端口8761

启动两个service-hello服务，分别暴露在8762和8763端口

可以看到service-hello服务，Availability Zones数量是2，也就是有两个实例在提供服务。

8762提供服务代码

    @RequestMapping("hello")    public String hello(@RequestParam String name){        return "hello "+name+",from service provider 1";    }

8763提供服务代码

    @RequestMapping("hello")    public String hello(@RequestParam String name){        return "hello "+name+",from service provider 2";    }

测试和验证

1 启动RibbontestApplication中的main函数

2 浏览器中输入
http://172.16.153.1:7071/hello?name=%E5%BC%A0%E5%B0%8F%E9%BE%99

结论

1 ribbon可以作为eureka服务的客户端，可以调通注册在eureka服务器上的服务
2 ribbon天生带着负载均衡的支持，负载策略可配置。
RibbontestApplication中ribbonRule方法返回的RandomRule即是随机策略。
其他负载策略

负载策略 备注 RoundRobinRule 轮询策略 AvailabilityFilteringRule 可用性过滤策略，可用性越强优先 WeightedResponseTimeRule 响应时间权重策略，响应时间越长，权重越小