这篇文章主要介绍了spring boot2X Consul如何通过RestTemplate实现服务调用,文中通过示例代码介绍的非常详细,对大家的学习或者工作具有一定的参考学习价值,需要的朋友可以参考下
Consul可以用于实现分布式系统的服务发现与配置
服务调用有两种方式:
A.使用RestTemplate 进行服务调用
负载均衡——通过Ribbon注解RestTemplate
B.使用Feign 进行声明式服务调用
负载均衡——默认使用Ribbon实现
先使用RestTemplate来实现
1.服务注册发现中心
启动Consul
consul agent -dev
2.服务端
在spring boot2X整合Consul 的基础上
添加服务provider,provider1
provider测试方法
package com.xyz.provider.controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class demoController { @RequestMapping("/hello") public String Hello(){ return "hello,provider"; } }
provider1测试方法
package com.xyz.provider1.controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; @RestController public class demoController { @RequestMapping("/hello") public String Hello(){ return "hello,another provider"; } }
启动provider和provider1
浏览器访问http://localhost:8500
有两个服务提供者节点实例
3.客户端
(1)添加依赖
<properties> <java.version>1.8</java.version> <spring-cloud.version>Greenwich.SR4</spring-cloud.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-consul-discovery</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement>
(2)添加配置
server.port=8015 spring.application.name=xyz-comsumer spring.cloud.consul.host=localhost spring.cloud.consul.port=8500 spring.cloud.consul.discovery.register=false spring.cloud.consul.discovery.health-check-url=/actuator/health spring.cloud.consul.discovery.heartbeat.enabled=true management.endpoints.web.exposure.include=* management.endpoint.health.show-details=always
(3)测试方法
获取所有注册的服务,从注册的服务中选取一个,服务调用
package com.xyz.comsumer.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.cloud.client.ServiceInstance; import org.springframework.cloud.client.discovery.DiscoveryClient; import org.springframework.cloud.client.loadbalancer.LoadBalancerClient; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.client.RestTemplate; @RestController public class HelloController { @Autowired private LoadBalancerClient loadBalancer; @Autowired private DiscoveryClient discoveryClient; private String serviceName = "service-provider"; @RequestMapping("/services") public Object services() { return discoveryClient.getInstances(serviceName); } @RequestMapping("/discover") public Object discover() { return loadBalancer.choose(serviceName).getUri().toString(); } @RequestMapping("/hello") public String hello() { ServiceInstance serviceInstance = loadBalancer.choose(serviceName); String callServiceResult = new RestTemplate().getForObject(serviceInstance.getUri().toString() + "/hello", String.class); return callServiceResult; } }
注:
客户端调用的服务名,是在服务端指定的,在服务端配置里使用 spring.cloud.consul.discovery.service-name指注册到 Consul 的服务名称
测试
启动Consul
启动provider和provider1
启动comsumer
测试地址 http://localhost:8015/services
返回结果
[ { "instanceId": "provider-8010", "serviceId": "service-provider", "host": "hkgi-PC", "port": 8010, "secure": false, "metadata": { "secure": "false" }, "uri": "http://hkgi-PC:8010", "scheme": null }, { "instanceId": "provider-8011", "serviceId": "service-provider", "host": "hkgi-PC", "port": 8011, "secure": false, "metadata": { "secure": "false" }, "uri": "http://hkgi-PC:8011", "scheme": null } ]
测试地址 http://localhost:8015/discover
返回结果
- http://hkgi-PC:8011 或 http://hkgi-PC:8011
- 测试地址 http://localhost:8015/hello
- 返回结果
- hello,provider 或 hello,another provider
注:
结果交替出现的,这是因为负载均衡器是采用的是轮询的方式
说明:
调用的过程:
A.通过LoadBalancerClient查询服务
B.通过RestTemplate调用远程服务
Ribbon负载均衡策略
- BestAvailableRule
- AvailabilityFilteringRule
- WeightedResponseTimeRule
- RetryRule
- RoundRobinRule
- RandomRule
- ZoneAvoidanceRule
自定义Ribbon负载均衡——使用随机访问策略
修改启动类
package com.xyz.comsumer; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.web.client.RestTemplate; @SpringBootApplication public class ComsumerApplication { public static void main(String[] args) { SpringApplication.run(ComsumerApplication.class, args); } @Bean @LoadBalanced public RestTemplate restTemplate(){ return new RestTemplate(); } }
服务调用
package com.xyz.comsumer.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.client.RestTemplate; @RestController public class RibbonHelloController { @Autowired private RestTemplate restTemplate; private String serviceName = "service-provider"; @RequestMapping("/ribbon/hello") public String hello() { String callServiceResult = restTemplate.getForObject("http://"+serviceName+"/hello", String.class); return callServiceResult; } }
配置添加
service-provider.ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RandomRule
重新启动 comsumer
测试地址 http://localhost:8015/ribbon/hello
输出的结果不再是交替出现,改为随机的了
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持易盾网络。