Day17_13_SpringCloud教程之Ribbon实战

Ribbon实战 注意:

本SpringCloud系列博客案例代码,是建立在一个共同的项目中,以后所有模块公共依赖包不再赘述,具体请参考Eureka实战篇.

https://blog.csdn.net/syc000666/article/details/95388985

org.springframework.bootspring-boot-starter-parent2.0.3.RELEASE
   UTF-8
   UTF-8UTF-81.8
   1.8
   1.8
   1.16.20

   
   Finchley.RELEASEorg.springframework.cloudspring-cloud-dependencies${spring-cloud.version}pomimport
      
      
      

      org.springframework.bootspring-boot-starter-weborg.projectlomboklombok${lombok.version}org.springframework.bootspring-boot-starter-testtestorg.springframework.bootspring-boot-maven-plugin

一. 创建Eureka Server模块 1. pom.xml中添加依赖

org.springframework.cloudspring-cloud-starter-netflix-eureka-server

2. 创建配置文件

server:
  port: 8761
spring:
  application:
    name: eurka-server
eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

3. 创建入口类

package com.syc.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

/**
 * 跟一一哥学SpringCloud微服务
 */
@EnableEurekaServer
@SpringBootApplication
public class EurekaApplication {

    public static void main(String[] args){
        SpringApplication.run(EurekaApplication.class,args);
    }
}

4. 项目结构



二. 创建一个服务提供者 1. 添加依赖

org.springframework.cloudspring-cloud-starter-netflix-eureka-client

2. 创建配置文件

server:
  port: 8762
spring:
  application:
    name: eureka-provider
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

注意:

本案例中共有2个服务提供者,代码一样,端口号分别为8762,8763,我们是在一个机器上部署两个不同端口号的服务实例.

3. 创建对外提供服务的接口

package com.syc.cloud.web;

import org.springframework.beans.factory.annotation.Value;
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 {

    @Value("${server.port}")
    private String port;

    @RequestMapping("/hello")
    public String sayHi(@RequestParam String name) {
        return "Hello," + name + "! This is " + port;
    }

}

4. 创建入口类

package com.syc.cloud;

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.client.RestTemplate;

/**
 *
 */
@SpringBootApplication
@EnableEurekaClient
public class ServiceProviderApplication {

    public static void main(String[] args) {
        SpringApplication.run(ServiceProviderApplication.class, args);
    }

}

5. 项目结构



三. 创建一个服务消费者 1. 添加依赖

org.springframework.cloudspring-cloud-starter-netflix-eureka-clientorg.springframework.cloudspring-cloud-starter-netflix-ribbon

2. 创建配置文件

server:
  port: 8764
spring:
  application:
    name: eureka-ribbon
eureka:
  instance:
    hostname: localhost
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3. 创建远程调用的service

package com.syc.cloud.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

/**
 * 远程调用eureka-provider的方法
 */
@Service
public class RibbonService {

    @Autowired
    private RestTemplate restTemplate;

    public String helloService(String name) {
        return restTemplate.getForObject("http://eureka-provider/hello?name="+name,String.class);
    }
}

4. 创建web层的controller

package com.syc.cloud.web;

import com.syc.cloud.service.RibbonService;
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
    private RibbonService helloService;

    @RequestMapping(value = "/hello")
    public String hello(@RequestParam String name){

        return helloService.helloService(name);
    }

}

5. 创建入口类

package com.syc.cloud;

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.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

/**
 *
 */
@SpringBootApplication
@EnableDiscoveryClient //注意:必须是@EnableDiscoveryClient注解,不能是@EnableEurekaClient,否则无法实现负载均衡.
//@EnableEurekaClient
public class ServiceRibbonApplication {

    public static void main(String[] args) {
        SpringApplication.run(ServiceRibbonApplication.class, args);
    }

    //创建负载均衡组件
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }

}

注意:

入口类必须添加@EnableDiscoveryClient注解,不能是@EnableEurekaClient注解,否则无法实现负载均衡.

四. 一个服务实例多端口同时启动配置

为了创建高可用的微服务,我们配置同一个服务实例按多个端口同时启动.

1. 首先配置8762端口的服务实例.



2. 然后复制8762端口的配置.



修改端口号为8763.

3. 创建一个Compound

注意就可以通过Compound来同时启动2个服务实例了.

五. 启动4个服务



此时已经成功的启动了4个服务实例.

接口测试:

第一次访问接口,端口号8762. 

第2次访问接口,端口号8763. 

可见默认采用的是轮询的负载均衡方式.

六. 项目架构



• 一个服务注册中心,eureka server,端口为8761;

• EUREKA-PROVIDER工程跑了两个实例,端口分别为8762,8763,分别向服务注册中心注册;

• EUREKA-RIBBON端口为8764,向服务注册中心注册;

• 当EUREKA-RIBBON通过restTemplate调用EUREKA-PROVIDER的hello接口时,因为用ribbon进行了负载均衡,会轮流的调用EUREKA-PROVIDER: 8762和8763 两个端口的hello接口.