何为Ribbon？
同Eureka一样，Ribbon 是Netflix 下的一个框架，它主要负责客户端应用实现【负载均衡】目的！
应用Ribbon：第一个Ribbon程序
搭建工程
- 新建一个web工程，即：Springboot（Maven） 工程 RibbonService：
RibbonService
| +---src
| +---main
| | +---java
| | | \---person
| | | \---jack
| | | | App.java
| | | |
| | | \---controller
| | | AppController.java
| | |
| | \---resources
| | application-8080.properties
| | application-8081.properties
+---pom.xml
pom.xml内容如下
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>1.5.9.RELEASE</version>
</dependency>
</dependencies>
- AppController 内容如下：
package person.jack.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import javax.servlet.http.HttpServletRequest;
@Controller
public class AppController {
@GetMapping("/info")
public @ResponseBody String info(HttpServletRequest req){
return "springBoot 是javaWEB开发最优美得姿势！"+req.getRequestURL();
}
}
- application-8080.properties 内容如下：
server.port=8080
- application-8081.properties 内容如下：
server.port=8081
- 配置maven启动
ribbonService-8080
Name: ribbonService-8080
Working dirctory: $Workspace/RibbonService
Command line:exec:java -Dexec.mainClass=person.jack.App -Dspring.profiles.active=8080
ribbonService-8081
Name: ribbonService-8081
Working dirctory: $Workspace/RibbonService
Command line:exec:java -Dexec.mainClass=person.jack.App -Dspring.profiles.active=8081
- 分别运行以上两个maven配置命令
页面全都打印：
springBoot 是javaWEB开发最优美得姿势！http://localhost:8080/info
# 即：一份程序运行了两个实例，8080、8081，完成负载均衡条件搭建
搭建Ribbon客户端
- 新建maven java 项目：RibbonClient
RibbonClient
+---src
| +---main
| | +---java
| | | \---person
| | | \---jack
| | | \---ribbon
| | | \---client
| | | RibbonClientTest.java
+---pom.xml
pom.xml 配置如下：
<properties>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>com.netflix.ribbon</groupId>
<artifactId>ribbon-core</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>com.netflix.ribbon</groupId>
<artifactId>ribbon-httpclient</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>com.netflix.ribbon</groupId>
<artifactId>ribbon-loadbalancer</artifactId>
<version>2.2.2</version>
</dependency>
<dependency>
<groupId>commons-configuration</groupId>
<artifactId>commons-configuration</artifactId>
<version>1.8</version>
</dependency>
<dependency>
<groupId>com.netflix.archaius</groupId>
<artifactId>archaius-core</artifactId>
<version>0.7.4</version>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>16.0</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5.1</version>
<configuration>
<source>1.6</source>
<target>1.6</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
</plugins>
</build>
- RibbonClientTest.java 内容如下：
package person.jack.ribbon.client;
import com.netflix.client.ClientFactory;
import com.netflix.client.http.HttpRequest;
import com.netflix.client.http.HttpResponse;
import com.netflix.config.ConfigurationManager;
import com.netflix.niws.client.http.RestClient;
public class RibbonClientTest {
public static void main(String[] args) throws Exception {
ConfigurationManager.getConfigInstance().setProperty(
"myClient.ribbon.listOfServers", "localhost:8080,localhost:8081");
RestClient client = (RestClient) ClientFactory.getNamedClient("myClient");
HttpRequest request = HttpRequest.newBuilder().uri("/info").build();
for(int i = 0; i < 10; i++) {
HttpResponse response = client.executeWithLoadBalancer(request);
String json = response.getEntity(String.class);
System.out.println(json);
}
}
}
- 运行以上main 函数，控制台输出：
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
springBoot 是javaWEB开发最优美的姿势！http://localhost:8081/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8081/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8081/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8081/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8081/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
由以上运行结果分析可知：Ribbon客户端 访问 /info 这个请求，该请求8080、8081都可提供，结果出现了“轮询”，压力被这两个实例分摊了。这就是Ribbon，其默认负载均衡算法采用的是“轮询”算法！
断开 8081端口服务，重新运行main函数，输出如下：
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
springBoot 是javaWEB开发最优美的姿势！http://localhost:8080/info
现在提供服务的只剩8080端口了，但并不影响服务的运行！负载功能测试成功！
