Spring Cloud Ribbon是一个基于http和tcp通讯协议的客户端负载均衡工具,它是基于Netflix Ribbon实现的。它可以独立存在于任何一个微服务系统中,实现远程服务调用和负载均衡。
创建一个spring cloud ribbon服务spring-cloud-ribbon
pom.xml内容如下:
<?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.example</groupId>
<artifactId>spring-cloud-ribbon</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>spring-cloud-ribbon</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>Edgware.SR2</spring-cloud.version>
</properties>
<dependencies>
<!-- 此项目为web项目 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- 连接到配置中心依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<!-- 作为客户端被eureka服务发现依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<!-- ribbon依赖 -->
<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>
在SpringCloudRibbonApplication添加@EnableDiscoveryClient注解,表示作为客户端注册到eureka。
添加RestTemplate的bean实例,@LoadBalanced表示实现客户端请求负载均衡,ribbon作为一个客户端服务,注册到eureka中心,eureka根据注册的实例名,查找服务部署,实现负载均衡。
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;
@SpringBootApplication
@EnableDiscoveryClient
public class SpringCloudRibbonApplication {
public static void main(String[] args) {
SpringApplication.run(SpringCloudRibbonApplication.class, args);
}
@Bean
@LoadBalanced
RestTemplate restTemplate (){
return new RestTemplate();
}
}
application.properties:
#eureka服务端地址
eureka.client.service-url.defaultZone=http://localhost:8761/eureka/
#服务端口号,默认为8080
server.port=8884
#服务注册到eureka的实例名
spring.application.name=spring-cloud-ribbon
创建一个HelloController,代码如下:
import com.perfiffer.example.service.HelloService;
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.RequestParam;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
@Autowired
HelloService helloService;
@RequestMapping(value = "/hello", method = RequestMethod.GET)
public String hello(@RequestParam String name) {
return helloService.hello(name);
}
}
HelloController调用HelloService的hello方法,HelloService如下:
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
@Service
public class HelloService {
@Autowired
RestTemplate restTemplate;
public String hello(String name) {
return restTemplate.getForObject("http://SPRING-CLOUD-DEMO/hello?name" + name, String.class);
}
}
HelloService的hello方法通过restTemplate实例调用远程的服务,SPRING-CLOUD-DEMO为已经注册到eureka中心的服务,SPRING-CLOUD-DEMO为服务的实例名。
spring-cloud-demo工程内容如下:
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.example</groupId>
<artifactId>spring-cloud-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>spring-cloud-demo</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>Edgware.SR2</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<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>
启动类:
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
@SpringBootApplication
@EnableDiscoveryClient
public class SpringCloudDemoApplication {
public static void main(String[] args) {
SpringApplication.run(SpringCloudDemoApplication.class, args);
}
}
applicatin.properties:
spring.application.name=spring-cloud-demo
server.port=8887
eureka.client.service-url.defaultZone=http://localhost:8761/eureka/
eureka.instance.prefer-ip-address=true
eureka.instance.instance-id=${spring.cloud.client.ipAddress}:${server.port}
HelloController.java
import com.perfiffer.example.service.IHelloService;
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;
@RestController
public class HelloController {
@Autowired
IHelloService helloService;
@RequestMapping(value = "/hello")
public String hello(@RequestParam String name) {
return helloService.hello(name);
}
}
IHelloService.java
public interface IHelloService {
String hello(String name);
}
HelloServiceImpl.java
import com.perfiffer.example.service.IHelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
@Service
public class HelloServiceImpl implements IHelloService {
@Override
public String hello(String name) {
return "hello, " + name;
}
}
启动spring-cloud-ribbon,访问http://localhost:8884/hello?tom,可以查看到返回信息hello, tom。如果部署了网关,也可通过网关访问接口。