Spring Cloud 之服务治理 - Eureka服务发现-消费者(负载均衡器Ribbon)
1.引入依赖
1
| compile "org.springframework.cloud:spring-cloud-starter-ribbon:${cloud_config}"
|
2.稍作配置
在bootstrap.yaml中加入Eureka server相关配置
1
2
3
4
5
6
7
8
| spring:
cloud:
config:
uri: http://localhost:8888
profile: rabbit
name: appliaction
username: pkaq
password: pkaqx
|
3.添加注解
4.来点代码
启动类代码
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
| @SpringBootApplication
@EnableEurekaClient
open class RibbonClientBooter: CommandLineRunner{
@Autowired
val builder: RestTemplateBuilder? = null
@Bean
@LoadBalanced
open fun restTemplate(): RestTemplate {
return builder!!.build()
}
@Throws(Exception::class)
override fun run(vararg args: String) {
println(" --- --- --- [ Ribbon client started ] --- --- --- ")
}
}
fun main(args: Array<String>) {
org.springframework.boot.SpringApplication.run(org.pkaq.RibbonClientBooter::class.java, *args)
}
|
Controller代码
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
| @RestController
class RibbonController {
@Autowired
var restTemplate: RestTemplate? = null
@RequestMapping("/Ribbon")
fun say(): String {
val microServiceNode = "tiger"
val serviceName = "say"
val url = "http://${microServiceNode}/${serviceName}"
return restTemplate!!.getForObject(url, String::class.java)+" - > Ribbon"
}
}
|
可以看到这里已经不用通过注入LoadBalancerClient获取serviceInstance的方式来拼接请求路径了,这是因为,当一个被@LoadBalanced注解修饰的RestTemplate对象向外发起HTTP请求时，会被LoadBalancerInterceptor类的intercept函数所拦截。由于我们在使用RestTemplate时候采用了服务名作为host，所以直接从HttpRequest的URI对象中通过getHost()就可以拿到服务名，然后调用execute函数去根据服务名来选择实例并发起实际的请求。
5.启动服务,大功告成
