SpringCloud Ribbon用戶端負載均衡子產品

說明

SpringCloud Ribbon是一個基于HTTP與TCP的用戶端負載均衡工具，它基于Netflix Ribbon實作。通過Spring Cloud的封裝，可以讓我們輕松地将面向服務的REST模版請求自動轉換成用戶端負載均衡的服務調用。

用戶端負載均衡：在用戶端負載均衡中，所有的用戶端節點都有一份自己要通路的服務端清單，這些清單統統都是從Eureka服務注冊中心擷取的。在Spring Cloud中我們如果想要使用用戶端負載均衡，方法很簡單，開啟@LoadBalanced注解即可，這樣用戶端在發起請求的時候會先自行選擇一個服務端，向該服務端發起請求，進而實作負載均衡。

目标

使用SpringCloud Eureka建立服務提供者和消費者，使用SpringCloud Ribbon實作用戶端負載均衡。

快速使用

（Eureka沿用上一篇的項目，首先啟動兩個Eureka注冊中心）

服務提供者*2

首先給出項目結構

1 更新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>yunlingfly</groupId>
	<artifactId>mavenspringcloudclient</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>mavenspringcloudclient</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.10.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.SR2</spring-cloud.version>
	</properties>

	<dependencies>
		<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>

	<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>
           

2 更新application.yml

eureka:
  enabled: true
  client:
    registerWithEureka: true
    fetchRegistry: true
    serviceUrl:
        # 如果是本機測試将xxx換成localhost即可，伺服器則填寫IP位址
      defaultZone: http://xxx.xxx.xxx.xxx:8761/eureka/,http://xxx.xxx.xxx.xxx:8762/eureka/
# 如果服務提供者不是運作在本機的話需要加上下面的注釋，否則注冊中心無法通過ip查找服務（從注冊中心的執行個體名稱也能看出來）
#  instance:
#    preferIpAddress: true
#    instance-id: ${spring.cloud.client.ipAddress}:${server.port}
#    hostname: ${spring.cloud.client.ipAddress}
#    ipAddress: xxx.xxx.xxx.xxx
server:
  port: 8763
info:
  name: 服務提供者-8763
  version: 0.0.1
spring:
  application:
    name: eureka-client
           

3 編寫啟動類

package yunlingfly.mavenspringcloudclient;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

// 啟動類
@SpringBootApplication
// Eureka服務提供者
@EnableDiscoveryClient
public class MavenspringcloudclientApplication {

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

4 編寫服務提供者的Controller層

package yunlingfly.mavenspringcloudclient.controller;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ServiceInstanceRestController {
	@Value("${server.port}")
	String port;

	@RequestMapping("/hi")
	public String home(@RequestParam String name) {
		return "hi " + name + ",i am from port:" + port;
	}

}
           

請另外再建立一個和這個服務提供者一樣的項目，隻需要改動application.yml的server.port屬性即可例如server.port=8765（不要與前面的重複）

服務消費者

首先給出項目結構

1 更新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>yunlingfly</groupId>
	<artifactId>mavenspringcloudribbon</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>mavenspringcloudribbon</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.10.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.SR2</spring-cloud.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-eureka</artifactId>
		</dependency>

		<!-- 用戶端均衡負載 -->
		<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>${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>
           

2 更新application.yml

eureka:
  client:
    serviceUrl:
      defaultZone: http://xxx.xxx.xxx.xxx:8761/eureka/,http://xxx.xxx.xxx.xxx:8762/eureka/
server:
  port: 8764
spring:
  application:
    name: service-ribbon
info:
  app:
    name: 一個消費者
    version: 0.0.1
           

3 編寫啟動類

package yunlingfly.mavenspringcloudribbon;

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;

// 啟動類
@SpringBootApplication
// 向服務中心注冊
@EnableDiscoveryClient
public class MavenspringcloudribbonApplication {

	public static void main(String[] args) {
		SpringApplication.run(MavenspringcloudribbonApplication.class, args);
	}
	@Bean
	// @LoadBalanced注解表明這個restRemplate開啟負載均衡的功能
	@LoadBalanced
	RestTemplate restTemplate() {
		return new RestTemplate();
	}
}
           

4 編寫服務消費者的Controller層

package yunlingfly.mavenspringcloudribbon.controller;

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;
import org.springframework.web.client.RestTemplate;

@RestController
public class HelloControler {
    @Autowired
    RestTemplate restTemplate;
    @RequestMapping(value = "/hi")
    public String hi(@RequestParam String name){
        return restTemplate.getForObject("http://eureka-client/hi?name="+name,String.class);
    }
}
           

運作

首先啟動服務提供者*2，然後啟動服務消費者，然後浏覽器輸入http://localhost:8764/hi?name=芸靈fly即可看到效果（服務由8763與8765端口的服務交替提供）

檢視Eureka發現Eureka-client的服務有兩個

注意事項：使用@LoadBalanced為RestTemplate開啟負載均衡；測試時如果服務提供者與服務消費者不在同一台機器上，需要加上eureka.instance的各種屬性配置，具體檢視上文application.yml的注釋