上面的Eurefa高可用依葫芦画瓢就弄，不是太明白怎么回事。但是有一点但是怎么去用呢，也就是怎么用负载均衡去调用。
注册中心server
添加依赖
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>Dalston.RC1</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
配置文件
server:
port: 8761
eureka:
instance:
hostname: localhost
client:
registerWithEureka: false
fetchRegistry: false
serviceUrl:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
上面的eureka.client.registerWithEureka= false表示为注册中心，自己不向自己注册
而eureka.client.fetchRegistry: false表示注册中心的职责就是维护服务实例，并不需要去检索服务。
启动类
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@EnableEurekaServer
@SpringBootApplication
public class AppServer {
public static void main(String[] args) {
SpringApplication.run(AppServer.class, args);
}
}
完成了注册中心server。
服务提供者client
依赖在service的pom文件中将
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
替换 替换 替换 替换 替换 替换
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
配置文件
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
server:
port: 8762
spring:
application:
name: service-hi
启动类
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@EnableEurekaClient
@RestController
public class AppClient2 {
public static void main(String[] args) {
SpringApplication.run(AppClient2.class, args);
}
@Value("${server.port}")
String port;
@RequestMapping("/hi")
public String home(@RequestParam String name) {
return "hi "+name+",i am from port:" +port;
}
}
client2和client一模一样，就是配置文件中server.port=8763
然后依次启动server，client，client2。
访问 http://localhost:8761/ 进入eurefa控制台，看到两个服务
Ribbon
依赖jar包在client的pom文件基础上加上
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
然后配置文件
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
server:
port: 8764
spring:
application:
name: service-ribbon
Controller
@RestController
public class HelloControler {
@Autowired
HelloService helloService;
@RequestMapping(value = "/hi")
public String hi(@RequestParam String name){
return helloService.hiService(name);
}
}
server
@Service
public class HelloService {
@Autowired
RestTemplate restTemplate;
public String hiService(String name) {
//通过启动类注入ioc容器的restTemplate来消费service-hi服务的“/hi”接口
//在ribbon中它会根据服务名来选择具体的服务实例，根据服务实例在请求的时候会用具体的url替换掉服务名
return restTemplate.getForObject("http://SERVICE-HI/hi?name="+name,String.class);
}
}
启动类
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
@EnableDiscoveryClient
public class AppRibbon {
public static void main(String[] args) {
SpringApplication.run(AppRibbon.class, args);
}
//启动时自动注入ioc
@Bean
@LoadBalanced
RestTemplate restTemplate() {
return new RestTemplate();
}
}
然后启动这个ribbon。在eruefa控制台也会多一个服务。
然后不断刷新 http://localhost:8764/hi?name=lijia 来查看负载均衡
在浏览器中 出现两个不同的端口号8762和8763，这里面负载均衡已经完成。
此时的架构图
- 一个服务注册中心，eureka server,端口为8761
- service-hi工程跑了两个实例，端口分别为8762,8763，分别向服务注册中心注册
- sercvice-ribbon端口为8764,向服务注册中心注册
- 当sercvice-ribbon通过restTemplate调用service-hi的hi接口时，因为用ribbon进行了负载均衡，会轮流的调用service-hi：8762和8763 两个端口的hi接口；
代码放在 https://github.com/lijiaccy/springcloud-study/tree/master/eurefa-Ribbon 上
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