原理:
其中涉及到3中角色:
服務注冊中心:作為eureka的一個server,提供服務注冊和發現的功能。在啟動類中加注解@EnableEurekaServer
服務提供者:作為eureka的一個用戶端元件,可以對外提供服務。在啟動類中加注解@EnableEurekaClient
服務消費者:作為eureka的一個用戶端元件,用來消費服務。在啟動類中加注解@EnableEurekaClient
過程:
1.服務注冊中心eureka server先啟動
2.eureka client的服務提供者向服務注冊中心eureka server進行注冊。
3.eureka client的服務消費者向服務注冊中心eureka server注冊,同時從注冊中心擷取一份服務注冊清單的資訊,該清單包含了所有向服務注冊中心eureka server注冊的服務資訊。擷取服務注冊清單資訊之後,服務消費者就知道服務提供者的IP位址,可以通過HTTP遠端排程來通路提供者提供的服務。
4.服務消費者和服務提供者對于服務注冊中心來講,都是用戶端。
consumer:
controller:
package com.ljf.weifuwu.springcloud.eureka.consumer.controller;
import com.ljf.weifuwu.springcloud.eureka.consumer.model.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
public class ConsumerUserController
{ @Autowired
private RestTemplate restTemplate;
@GetMapping("/consumer-eureka/{id}")
public User findById(@PathVariable Long id) {
return this.restTemplate.getForObject("http://localhost:7900/eureka-provider/" + id, User.class);
//為何不能用下面這種方式??????????
//return this.restTemplate.getForObject("http://ms-eureka-provider/eureka-provider/" + id, User.class);
}
}
啟動類:
package com.ljf.weifuwu.springcloud.eureka.consumer;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
/**
* Hello world!
*
*/
@SpringBootApplication
@EnableEurekaClient
public class ConsumerEurekaApp
{ @Bean
public RestTemplate restTemplate() {
return new RestTemplate();
}
public static void main( String[] args )
{
SpringApplication.run(ConsumerEurekaApp.class, args);
System.out.println( "eureka-consumer啟動起來了!!!" );
}
}
provider:
controller:
package com.ljf.weifuwu.springcloud.eureka.provider.controller;
import com.ljf.weifuwu.springcloud.eureka.provider.model.EurekaUser;
import com.ljf.weifuwu.springcloud.eureka.provider.respository.EurekaUserRespository;
import com.netflix.appinfo.InstanceInfo;
import com.netflix.discovery.EurekaClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class UserController {
@Autowired
@Qualifier("eurekaClient")
private EurekaClient eurekaClient;
@Autowired
private DiscoveryClient discoveryClient;
@Autowired
private EurekaUserRespository userRepository;
@GetMapping("/eureka-instance")
public String serviceUrl() {
//和配置檔案配置的application.name=ms-eureka-provider保持一緻
//擷取配置檔案的ip和端口号:http://localhost:7900/eureka-instance
InstanceInfo instance = this.eurekaClient.getNextServerFromEureka("ms-eureka-provider", false);
return instance.getHomePageUrl();
}
@GetMapping("/instance-info")
public ServiceInstance showInfo() {
//http://localhost:7900/instance-info
//"host":"192.168.1.225","port":7900,"serviceId":"ms-eureka-provider","metadata":{},"secure":false,"uri":"http://192.168.1.225:7900"}
ServiceInstance localServiceInstance = this.discoveryClient.getLocalServiceInstance();
return localServiceInstance;
}
@GetMapping("/eureka-provider/{id}")
public EurekaUser getSingleUser(@PathVariable Long id){
return this.userRepository.findOne(id);
}
}
respository:
package com.ljf.weifuwu.springcloud.eureka.provider.respository;
import com.ljf.weifuwu.springcloud.eureka.provider.model.EurekaUser;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
@Repository
public interface EurekaUserRespository extends JpaRepository<EurekaUser, Long> {
}
data.sql:
insert into eurekauser(id,username, name, age, balance) values(1,'user1', 'liu', 20, 100.00);
insert into eurekauser(id,username, name, age, balance) values(2,'user2', 'jian', 20, 100.00);
insert into eurekauser(id,username, name, age, balance) values(3,'user3', 'fu', 20, 100.00);
insert into eurekauser(id,username, name, age, balance) values(4,'user4', 'jurf', 20, 100.00);
schema.sql:
drop table eurekauser if exists;
create table eurekauser(
id bigint generated by default as identity,
username varchar(40),
name varchar(20),
age int(3),
balance decimal(10,2),
primary key(id)
);
啟動類:
package com.ljf.weifuwu.springcloud.eureka.provider;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
/**
* Hello world!
*
*/
@SpringBootApplication
@EnableEurekaClient
public class EurekaProviderApp
{
public static void main( String[] args )
{
SpringApplication.run(EurekaProviderApp.class,args);
System.out.println( "eurka中的提供者啟動成功!" );
}
}
頁面通路:http://localhost:7901/consumer-eureka/1