LoadBalancerClient
使用Spring Cloud提供的负载均衡器客户端来实现服务的消费。
首先创建一个服务消费者工程,命名为com.david.consumer,并在pom.xml中添加依赖:
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.david</groupId> <artifactId>consumer</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>consumer</name> <description>Demo project for Spring Boot</description> <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</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Edgware.SR2</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> </project>
配置application.yml指定eureka注册中心地址:
spring:
application:
name: david-eureka-consumer
server:
port: 8763
eureka:
client:
service-url:
default-zone: http://localhost:8761/eureka/
在工程的启动类中,通过@EnableDiscoverClient向服务中心注册,并向程序的ioc注入一个bean:restTemplate。
//向服务中心注册 @EnableDiscoveryClient @SpringBootApplication public class ConsumerApplication { //向ioc注入一个bean:restTemplate @Bean public RestTemplate restTemplate(){ return new RestTemplate(); } public static void main(String[] args) { SpringApplication.run(ConsumerApplication.class, args); } }
新建TestController
@RestController public class TestController { @Autowired LoadBalancerClient loadBalancerClient; @Autowired RestTemplate restTemplate; @GetMapping("/consumer") public String test(){ ServiceInstance serviceInstance = loadBalancerClient.choose("david-eureka-client"); String url = "http://" + serviceInstance.getHost() +":" + serviceInstance.getPort() + "/test"; System.out.println(url); return restTemplate.getForObject(url,String.class); } }
我们注入了LoadBalancerClient和RestTemplate,并在/consumer方法中,先通过loadbalancerClient中的choose函数来负载均衡的选出一个david-eureka-client的服务实例,这个服务实例的基本信息存储在ServiceInstance中,然后通过这些对象的信息拼接处访问/test 接口的详细地址,最后再利用RestTemplate对象实现对服务提供者接口的调用。
访问http://localhost:8763/consumer