springcloud(第七篇)springcloud ribbon with eureka

spring cloud ribbon with eureka

introduction

在上一篇中阐述了

ribbon

的基本用法，但是可以发现服务列表是通过配置得来的，实际

情况通常是由负载均衡+服务发现来实现的，通过服务发现获取服务列表，负载均衡通过rule选择要调用的服务。服务发现可以通过

eureka

来实现，后期会讲解利用

consul

做服务发现。

eureka discovery service

eureka服务发现在前面的文章中已经提供到，这里直接给出代码

首先是 eureka server

package com.lkl.springcloud.ribbon;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableAutoConfiguration
@EnableEurekaServer
public class EurekaServerApplication {

public static void main(String[] args) {
new SpringApplicationBuilder(EurekaServerApplication.class).properties(
"spring.config.name:eureka", "logging.level.com.netflix.discovery:OFF")
.run(args);
}

}

对应配置文件：

server.port=8761
spring.application.name= eureka
eureka.client.registerWithEureka=false
eureka.client.fetchRegistry=false

在eureka上进行服务注册

SimpleApplication.java

package com.lkl.springcloud.ribbon;

import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@Configuration
@EnableAutoConfiguration
@EnableDiscoveryClient
@RestController
public class SimpleApplication {

@RequestMapping("/")
public String hello() {
return "Hello";
}

public static void main(String[] args) {
new SpringApplicationBuilder(SimpleApplication.class).properties(
"spring.config.name:simple").run(args);
}
}

对应client配置

server.port= 8081
spring.application.name= simple
eureka.instance.leaseRenewalIntervalInSeconds= 10
eureka.client.registryFetchIntervalSeconds= 5
eureka.client.serviceUrl.defaultZone= http://localhost:${eureka.port:8761}/eureka/

ribbon + eureka

Application.java

package com.lkl.springcloud.ribbon;

import org.springframework.beans.factory.annotation.Autowired;
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.http.client.SimpleClientHttpRequestFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

/**
* Created by liaokailin on 16/5/9.
*/
@SpringBootApplication
@EnableDiscoveryClient
@RestController
public class Application {

@Autowired
RestTemplate client;

/**
* LoadBalanced 注解表明restTemplate使用LoadBalancerClient执行请求
*
* @return
*/
@Bean
@LoadBalanced
public RestTemplate restTemplate() {
RestTemplate template = new RestTemplate();
SimpleClientHttpRequestFactory factory = (SimpleClientHttpRequestFactory) template.getRequestFactory();
factory.setConnectTimeout(3000);
factory.setReadTimeout(3000);
return template;
}

@RequestMapping("/")
public String helloWorld() {
return client.getForObject("http://simple/", String.class);
}

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

}

EnableDiscoveryClient

表明为eureka client 通过可以进行服务发现

RestTemplate

构建

RestTemplate

对应的bean，在method上使用注解

LoadBalanced

表示restTemplate使用

LoadBalancerClient

执行请求

对应配置文件

spring.application.name=RibbionClient
eureka.instance.leaseRenewalIntervalInSeconds= 10
eureka.client.registryFetchIntervalSeconds= 5
eureka.client.serviceUrl.defaultZone= http://localhost:${eureka.port:8761}/eureka/[/code] 
run 
Application.java
后访问http://localhost:8080/调用
helloWorld()
方法，该方法访问
http://simple/
 其中的
simple
为
SimpleApplication.java


在eureka上注册的service id，即实际调用

@RequestMapping("/")
public String hello() {
return "Hello";
}


因此得到返回结果
Hello
.

ok ~ it’s work !  more about is here