spring-cloud（一）服务的注册和发现

1.SpringClound特点

Spring Cloud focuses on providing good out of box experience for typical use cases and extensibility mechanism to cover others.

• Distributed/versioned configuration
• Service registration and discovery
• Routing
• Service-to-service calls
• Load balancing
• Circuit Breakers
• Distributed messaging

2.创建服务注册中心

2.1创建spring-boot工程后再依赖中添加eureka-server依赖
<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    </dependency>
</dependencies>
2.2添加工程配置，配置工程为注册中心

server:
  port: 8761

eureka:
  instance:
    hostname: localhost
  client:
    registerWithEureka: false（表明是服务端）
    fetchRegistry: false（表明是服务端）
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

spring:
  application:
    name: eurka-server
2.3在启动类中添加注册中心的注解

@SpringBootApplication
@EnableEurekaServer（）
public class EurekaServerApplication {

    public static void main(String[] args) {
        SpringApplication.run( EurekaServerApplication.class, args );
    }
}
2.4eureka server 是有界面的，启动工程,打开浏览器访问： http://localhost:8761 ,界面如下：

3.创建服务注册客户端中心

3.1创建spring-boot工程后再依赖中添加eureka-client依赖
<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
</dependencies>
3.2添加工程配置，配置工程为注册中心

server:
  port: 8762

spring:
  application:
    name: service-hi

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/

3.3在启动类中添加注册中心的注解

@SpringBootApplication
@EnableEurekaClient
@RestController
public class ServiceHiApplication {

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

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

    @RequestMapping("/hi")
    public String home(@RequestParam(value = "name", defaultValue = "forezp") String name) {
        return "hi " + name + " ,i am from port:" + port;
    }

}

2.4启动工程后发现client已经在server中注册

需要指明spring.application.name,这个很重要，这在以后的服务与服务之间相互调用一般都是根据这个name 。 启动工程，打开http://localhost:8761 ，即eureka server 的网址：

你会发现一个服务已经注册在服务中了，服务名为SERVICE-HI ,端口为7862

这时打开 http://localhost:8762/hi?name=forezp ，你会在浏览器上看到 :

hi forezp,i am from port:8762