Spring Cloud 服务消费 [ Ribbon ]

Ribbon是一个基于HTTP和TCP客户端的负载均衡器

Spring Cloud 服务注册与发现 [ eureka ] 创建了一个简单的服务注册中心。

应为要运行多个应用作为服务提供方，所以将 eureka-client 打包。

准备环境：

1、运行 eureka 服务注册中心

2、运行两个 eureka-client 应用,用--server.port指定端口

eureka-client-0.0.1-SNAPSHOT.jar

eureka-client-0.0.1-SNAPSHOT.jar --server.port=9762

此时访问 http://localhost:9760/ 发现eureka-client-test服务有两个单元运行。



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创建 SpringBoot应用，添加 ribbon依赖和 eureka 依赖，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.forwy</groupId>
<artifactId>eureka-ribbon</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

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

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.6.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.SR3</spring-cloud.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-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>

配置文件

spring.application.name=ribbon-consumer

server.port=9991

eureka.client.serviceUrl.defaultZone=http://localhost:9760/eureka/

启动类加上 @EnableDiscoveryClient注解，并加上一个 RestTemplate 的bean

package com.forwy.eurekaribbon;

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
@SpringBootApplication
public class EurekaRibbonApplication {

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

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

编写一个 ConsumerController，实现调用 eureka-client 的eruekaTest这个方法

package com.forwy.eurekaribbon.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class ConsumerController {

@Autowired
RestTemplate rt;

@RequestMapping(value = "/eurekaTest",
method = RequestMethod.GET
)
public String eurekaTest() {
return rt.getForEntity("http://EUREKA-CLIENT/eurekaTest?w=hello&y=skye", String.class).getBody();
}

}

至此，ribbon负载均衡应用完毕

--------------------

启动 ribbon 应用，访问两次 http://localhost:9991/eurekaTest
发现两个 eureka 实例分别打印出一条日志，说明各调用一次

2017-09-05 16:51:15.899  INFO 9692 --- [nio-9761-exec-6] c.f.e.controller.EurekaController        : the host is : DESKTOP-LSB5ED0 ,the port is : 9761, the servier id is : eureka-client

2017-09-05 16:51:11.116  INFO 13744 --- [nio-9762-exec-1] c.f.e.controller.EurekaController        : the host is : DESKTOP-LSB5ED0 ,the port is : 9762, the servier id is : eureka-client