Spring Cloud Eureka？
基于Netflix Eureka做了二次封装
两个组件组成：
Eureka Server 注册中心
Eureka Client 服务发现
（实现）Spring Cloud Eureka Server：
pom.xml
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
Application.java
@EnableEurekaServer
public class Application {
......
application.yml
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/
#表示是否将自己注册在EurekaServer上，默认为true。由于当前应用就是EurekaServer，所以置为false
register-with-eureka: false
#关闭注册保护机制
# server:
# enable-self-preservation: false
spring:
application:
name: eureka
server:
port: 8761
（实现）Spring Cloud Eureka Client：
pom.xml
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
Application.java
@EnableDiscoveryClient
public class Application {
......
application.yml
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/
#自定义链接
# instance:
# hostname: clientName
spring:
application:
name: client
Spring Cloud Eureka 高可用
启动多份Eureka后对其进行互相注册
Eureka1 端口8761
eureka:
client:
service-url:
defaultZone: http://localhost:8762/eureka/
spring:
application:
name: eureka
Eureka2 端口8762
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/
spring:
application:
name: eureka
Client
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/
spring:
application:
name: client
应用间通信的两种方式
1）RestTemplate：
利用@LoadBanlancer，然后再使用RestTemplate
2）Feign
在pom.xml中增加feign依赖，在启动类加上注解@EnableFeignClients，声明要调用的方法 @FeignClient @GetMapping
RestTemplate
第一种方式(直接使用restTemplate,url写死)
RestTemplate restTemplate = new RestTemplate();
String response = restTemplate.getForObject("http://localhost:8080/msg", String.class);
第二种方式(利用loadBalancerClient通过应用名称获取url,然后再使用restTemplate)
ServiceInstance serviceInstance = loadBalancerClient.choose("PRODUCT");
String url = String.format("http://%s:%s",serviceInstance.getHost(),serviceInstance.getPort()) + "/msg";
String response = restTemplate.getForObject(url, String.class);
第三种方式(利用@LoadBalancer,可在restTemplate里使用应用名字)
@Component
public class RestTemplateConfig {
@Bean
@LoadBalanced
public RestTemplate restTemplate(){
return new RestTemplate();
}
}
String response = restTemplate.getForObject("http://PRODUCT/msg", String.class);
Feign
Client
pom.xml
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
Application.java
@EnableFeignClients
public class Application {
......
ProductClient
@FeignClient(name = "product")
public interface ProductClient {
@GetMapping("/msg")
String productMsg();
}
@Autowired
private ProductClient productClient;
String response = productClient.ProductMsg();
