Ribbon:提供云端负载均衡,有多种负载均衡策略可供选择,可配合服务发现和断路器使用。
上一篇简单讲解了eureka的使用,这一篇文章基于上一篇的基础上,讲一下springcloud的另一个重要的组件ribbon。
这篇文章需要新建三个工程,service(8762),service(8763),service-ribbon(8764),三个服务分别向eureka-server注册中心注册,本文的服务使用的注册中心都是本人创建的测试eureka--http://eureka.dalaoyang.cn。
首先新建一个service(8762),括号内的8762是项目的端口号,加入eureka依赖,pom文件如下:
<?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.dalaoyang</groupId>
<artifactId>springcloud_service</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>springcloud_service</name>
<description>springcloud_service</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.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>Edgware.SR1</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>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
配置文件
##端口号
server.port=8762
##服务名称
spring.application.name=service
##注册中心地址
eureka.client.service-url.defaultZone=http://eureka.dalaoyang.cn/eureka/
启动类使用注解@EnableEurekaClient向注册中心注册,代码如下:
package com.dalaoyang;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@RestController
@EnableEurekaClient
public class SpringcloudServiceApplication {
public static void main(String[] args) {
SpringApplication.run(SpringcloudServiceApplication.class, args);
}
@Value("${server.port}")
String port;
@Value("${spring.application.name}")
String serviceName;
@GetMapping("/")
public String index(){
return "serviceName=" + serviceName + "-------port=" + port;
}
}
到这里service(8762)创建完成,然后复制一个项目,端口号改为8763作为service(8763)。
然后新建项目service-ribbon(8764),pom文件加入ribbon依赖,pom完整代码如下:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.dalaoyang</groupId>
<artifactId>springcloud_ribbon</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>springcloud_ribbon</name>
<description>springcloud_ribbon</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Edgware.SR1</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${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>
配置文件如下:
##端口号
server.port=8764
##服务名称
spring.application.name=service_ribbon
##注册中心地址
eureka.client.service-url.defaultZone=http://eureka.dalaoyang.cn/eureka/
由于只是一个简单demo,所有我将java代码都写在了启动类里面,解释一下,@LoadBalanced放在RestTemplate上面,表明RestTemplate开启负载均衡。代码如下:
package com.dalaoyang;
import org.springframework.beans.factory.annotation.Value;
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.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
@EnableEurekaClient
@RestController
public class SpringcloudRibbonApplication {
public static void main(String[] args) {
SpringApplication.run(SpringcloudRibbonApplication.class, args);
}
@Bean
@LoadBalanced
RestTemplate restTemplate() {
return new RestTemplate();
}
@Value("${server.port}")
String port;
@Value("${spring.application.name}")
String serviceName;
@GetMapping("/")
public String index(){
return restTemplate().getForObject("http://service/",String.class);
}
}
分别启动service(8762),service(8763),service-ribbon(8764)三个工程。
先查看http://eureka.dalaoyang.cn/,可以看到三个实例注册成功。如下图:
image
多次访问 http://localhost:8764/,可以看到页面交替显示
image
image
可以看到负载均衡已经做到了。
完整项目流程如下图:
image
源码下载 :大老杨码云
个人网站:https://dalaoyang.cn