Spring Cloud之Ribbon+Rest调用负载均衡

创建Maven工程greeting-rest

导入依赖

pom.xml

<parent>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-starter-parent</artifactId>    <version>1.5.2.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></properties><dependencies>    <dependency>        <groupId>org.springframework.cloud</groupId>        <artifactId>spring-cloud-starter-eureka</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-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>Dalston.RC1</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><repositories>    <repository>        <id>spring-milestones</id>        <name>Spring Milestones</name>        <url>https://repo.spring.io/milestone</url>        <snapshots>            <enabled>false</enabled>        </snapshots>    </repository></repositories>

application.yml

eureka:  client:    serviceUrl:      defaultZone: http://localhost:8761/eureka/server:  port: 8764spring:  application:    name: greeting-rest

Application

package com.matrix.ribbon;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.client.discovery.EnableDiscoveryClient;import org.springframework.cloud.client.loadbalancer.LoadBalanced;import org.springframework.context.annotation.Bean;import org.springframework.web.client.RestTemplate;// @EnableDiscoveryClient，向eureka注册自己作为一个服务的调用client// 之前的服务，EnableEurekaClient，代表的是向eureka注册自己，将自己作为一个服务@SpringBootApplication@EnableDiscoveryClientpublic class GreetingRestApplication {    public static void main(String[] args) {        SpringApplication.run(GreetingRestApplication.class, args);    }    // 在spring容器中注入一个bean，RestTemplate，作为rest服务接口调用的客户端    // @LoadBalanced标注，代表对服务多个实例调用时开启负载均衡    @Bean    @LoadBalanced    public RestTemplate restTemplate() {        return new RestTemplate();    }}

调用service-say-hello

package com.matrix.ribbon.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.web.client.RestTemplate;// 写一个服务，注入RestTemplate服务调用客户端@Servicepublic class GreetingService {    @Autowired    private RestTemplate restTemplate;    // 用SAY-HELLO-SERVICE这个服务名替代实际的ip地址    // ribbon负载在多个服务实例之间负载均衡，每次调用随机挑选一个实例，然后替换服务名    public String greeting(String name) {        return restTemplate.getForObject("http://SERVICE-SAY-HELLO/sayHello?name=" + name, String.class);    }}

controller

package com.matrix.ribbon.controller;import com.matrix.ribbon.service.GreetingService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestParam;import org.springframework.web.bind.annotation.RestController;@RestControllerpublic class GreetingController {    @Autowired    private GreetingService greetingService;    @RequestMapping(value = "/greeting")    public String greeting(@RequestParam String name) {        return greetingService.greeting(name);    }}

多次访问http://localhost:8764/greeting?name=matrix，发现每次访问的端口都不一样，在多个服务实例之间负载均衡了