Ribbon【入门】

公共依赖：

<parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>2.0.3.RELEASE</version>

        <relativePath/>

</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>Finchley.RELEASE</spring-cloud.version>

</properties>

<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>

1、创建eureka-server注册中心工程

a、eureka-server工程pom依赖：

<!--加上上面的公共依赖-->

<dependencies>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>

        </dependency>

</dependencies>

<build>

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

        </plugins>

</build>

b、eureka-server启动类：

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication

@EnableEurekaServer

public class EurekaServerApplication {

    public static void main(String[] args) {

        SpringApplication.run(EurekaServerApplication.class, args);

    }

}

c、eureka-server工程配置文件：eureka-server\src\main\resources\bootstrap.yml

server:

  port: 8888

eureka:

  instance:

    hostname: localhost

  client:

    registerWithEureka: false

    fetchRegistry: false

    serviceUrl:

      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

d、启动注册中心

mvn spring-boot:run

2、创建demo-client服务工程

a、demo-client工程pom配置：

<!--加上上面的公共依赖-->

<dependencies>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>

        </dependency>

</dependencies>

<build>

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

        </plugins>

</build>

b、demo-client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 ClientApplication {

    public static void main(String[] args) {

        SpringApplication.run(ClientApplication.class, args);

    }

}

c、demo-client工程配置文件：demo-client\src\main\resources\bootstrap.yml

server:

  port: 7070

spring:

  application:

    name: client

eureka:

  client:

    serviceUrl:

      defaultZone: http://${eureka.host:127.0.0.1}:${eureka.port:8888}/eureka/

  instance:

    prefer-ip-address: true

d、编写测试接口：

import javax.servlet.http.HttpServletRequest;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RestController;

/**

 * 测试API

 */

@RestController

public class TestController {

    @GetMapping("/testApi")

    public String testApi(Integer a, Integer b, HttpServletRequest request) {

        return " From Port: " + request.getServerPort() + ", Result: " + (a + b);

    }

}

e、启动工程

mvn spring-boot:run

mvn spring-boot:run -Dserver.port=7171

启动了2个工程实例，一个端口是7070，一个是7171

3、创建demo-ribbon客户端工程

a、demo-ribbon工程pom依赖：

<!--加上上面的公共依赖-->

<dependencies>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>

        </dependency>

</dependencies>

<build>

        <plugins>

            <plugin>

                <groupId>org.springframework.boot</groupId>

                <artifactId>spring-boot-maven-plugin</artifactId>

            </plugin>

        </plugins>

</build>

b、demo-ribbon工程启动类：

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 RibbonLoadbalancerApplication {

    public static void main(String[] args) {

        SpringApplication.run(RibbonLoadbalancerApplication.class, args);

    }

    
　　 //声明该RestTemplate用于负载均衡

    @Bean

    @LoadBalanced

    public RestTemplate restTemplate() {

        return new RestTemplate();

    }

}

c、编写一个测试接口：

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RestController;

import org.springframework.web.client.RestTemplate;

@RestController

public class TestController {

    @Autowired

    private RestTemplate restTemplate;

    @GetMapping("/testApi")

    public String testApi(Integer a, Integer b) {
　　　　 //使用RestTemplate调用demo-client工程暴露的测试API接口

        String result = restTemplate.getForObject("http://CLIENT/testApi?a=" + a + "&b=" + b, String.class);

        System.out.println(result);

        return result;

    }

}

d、demo-ribbon工程配置文件：demo-ribbon\src\main\resources\bootstrap.yml

spring:

  application:

    name: ribbon-loadbalancer

server:

  port: 7777

eureka:

  client:

    serviceUrl:

      defaultZone: http://${eureka.host:127.0.0.1}:${eureka.port:8888}/eureka/

  instance:

    prefer-ip-address: true

e、启动demo-ribbon工程：

mvn spring-boot:run

4、访问 localhost:7777/testApi?a=2019&=2020

从结果可以看到这次访问的是7171端口服务。

从下面的控制台输出可以看出，ribbon在做负载均衡的时候，默认使用的是轮询的方式！

入门成功！！！