5. Spring Cloud 之服务治理 - Eureka服务

本部分需要依赖之前的配置中心和服务注册中心、服务提供者三个示例代码运行

三种方式

• RestTemplate
• Ribbon
• Feign

下面描述的是通过RestTemplate的方式进行服务调用

• RestTemplate
  　　RestTemplate是Spring提供的用于访问Rest服务的客户端，RestTemplate提供了多种便捷访问远程Http服务的方法，能够大大提高客户端的编写效率
  1.引入依赖

compile "org.springframework.cloud:spring-cloud-starter-eureka:${cloud_config}"

2.稍作配置
在bootstrap.yaml中加入Eureka server相关配置

spring:
    cloud:
        config:
            uri: http://localhost:8888
                profile: rabbit
                name: appliaction
                username: pkaq
                password: pkaqx

3.添加注解

@EnableEurekaClient

4.来点代码

@SpringBootApplication
@EnableEurekaClient
open class RabbitClientBooter: CommandLineRunner{
   //spring默认已注入RestTemplateBuilder实例
    @Autowired
    val builder: RestTemplateBuilder? = null
    
    // 实例化restTemplate
    @Bean
    open fun restTemplate(): RestTemplate {
        return builder!!.build()
    }

    @Throws(Exception::class)
    override fun run(vararg args: String) {
        println("  --- --- --- [ Rabbit client started ] --- --- ---  ")
    }
}

fun main(args: Array<String>) {
    org.springframework.boot.SpringApplication.run(org.pkaq.RabbitClientBooter::class.java, *args)
}

Controller代码

@RestController
class RabbitController {

@Autowired
var loadBalancerClient: LoadBalancerClient? = null;

@Autowired
var restTemplate: RestTemplate? = null

@RequestMapping("/jump")
    fun say(): String {
        // 这里配置要调用发的服务提供者的spring.
        var microServiceNode = "tiger"
        var serviceName = "say"
        var serviceInstance  = loadBalancerClient!!.choose(microServiceNode)
        
        var url = "http://"+serviceInstance.host+":"+serviceInstance.port+"/"+serviceName
        
        return restTemplate!!.getForObject(url, String::class.java)+" - > Rabbit"
    }
}

5.启动服务,大功告成