Ribbon: Provides cloud load balancing, with a variety of load balancing strategies to choose from, which can be used with service discovery and circuit breakers.
The previous article briefly explained the use of eureka. Based on the previous article, this article talks about another important component of springcloud, the ribbon.
This article needs to create three new projects, service (8762), service (8763), service-ribbon (8764), and the three services are registered with the eureka-server registry. The services used in this article are all created by me. Test eureka – http://eureka.dalaoyang.cn .
First create a new service (8762), the 8762 in brackets is the port number of the project, add the eureka dependency, the pom file is as follows:
<?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>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>configuration file
##端口号
server.port=8762
##服务名称
spring.application.name=service
##注册中心地址
eureka.client.service-url.defaultZone=http://eureka.dalaoyang.cn/eureka/The startup class uses the annotation @EnableEurekaClient to register with the registry. The code is as follows:
package com.dalaoyang;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@RestController
@EnableEurekaClient
public class SpringcloudServiceApplication {
public static void main(String[] args) {
SpringApplication.run(SpringcloudServiceApplication.class, args);
}
@Value("${server.port}")
String port;
@Value("${spring.application.name}")
String serviceName;
@GetMapping("/")
public String index(){
return "serviceName=" + serviceName + "-------port=" + port;
}
}Here the service (8762) is created, then copy a project and change the port number to 8763 as the service (8763).
Then create a new project service-ribbon (8764), add the ribbon dependency to the pom file, and the complete pom code is as follows:
<?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>
The configuration file is as follows:
##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/Since it's just a simple demo, I wrote all the java code in the startup class. To explain, @LoadBalanced is placed on RestTemplate, indicating that RestTemplate enables load balancing. code show as below:
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);
}
}Start three projects, service (8762), service (8763), and service-ribbon (8764).
Check http://eureka.dalaoyang.cn/ first , you can see that the three instances are successfully registered. As shown below:
Visit http://localhost:8764/ multiple times , and you can see that the pages are displayed alternately
You can see that the load balancing has been done.
The complete project process is as follows:
Source code download: Da Lao Yang Code Cloud
Personal website: https://dalaoyang.cn