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前面讲了eureka服务注册与发现,但是结合eureka集群的服务调用没讲。
这里的话 就要用到Ribbon,结合eureka,来实现服务的调用; 简介 Ribbon是Netflix发布的负载均衡器,它有助于控制HTTP和TCP的客户端的行为。为Ribbon配置服务提供者地址后,Ribbon就可基于某种负载均衡算法,自动地帮助服务消费者去请求。Ribbon默认为我们提供了很多负载均衡算法,例如轮询、随机等。当然,我们也可为Ribbon实现自定义的负载均衡算法。 在Spring Cloud中,当Ribbon与Eureka配合使用时,Ribbon可自动从Eureka Server获取服务提供者地址列表,并基于负载均衡算法,请求其中一个服务提供者实例。展示了Ribbon与Eureka配合使用时的架构。 初步应用 Ribbon是客户端负载均衡,所以肯定集成再消费端,也就是consumer端 我们修改microservice-student-consumer-80 首先,引入依赖,pom.xml 加入 ribbon相关依赖org.springframework.cloud spring-cloud-starter-eureka org.springframework.cloud spring-cloud-starter-ribbon org.springframework.cloud spring-cloud-starter-config
application.yml加
server: port: 80 context-path: /eureka: client: service-url: defaultZone: http://eureka2001.zxp.com:2001/eureka/,http://eureka2002.zxp.com:2002/eureka/,http://eureka2003.zxp.com:2003/eureka/ register-with-eureka: false
ribbon结合eureka来调用服务提供者;
SpringCloudConfig也改成 要加个负载均衡配置 @LoadBalancedpackage com.zxp.microservicestudentconsumer80.config;import org.springframework.cloud.client.loadbalancer.LoadBalanced;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.web.client.RestTemplate;@Configurationpublic class SpringCloudConfig { @LoadBalanced // 引入ribbon负载均衡 @Bean public RestTemplate getRestTemplate(){ return new RestTemplate(); }}
因为和eureka整合,所以启动类StudentConsumerApplication_80 加个注解 @EnableEurekaClient
package com.zxp.microservicestudentconsumer80;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;import org.springframework.cloud.netflix.eureka.EnableEurekaClient;import org.springframework.cloud.netflix.feign.EnableFeignClients;@EnableEurekaClient@SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})public class MicroserviceStudentConsumerFeign80Application { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentConsumerFeign80Application.class, args); }}
这里还有一个,要修改下StudentConsumerController的PRE_HOST,改成指定的微服务应用名称;
当然这里要先在服务提供者microservice-student-provider-1001的application.yml加下配置,指定下应用名称:application: name: microservice-student
我们的微服务应用名称是 microservice-student
所以服务调用者这边的控制器里PRE_HOST改成 http://MICROSERVICE-STUDENT即可; MICROSERVICE-STUDENT为Eureka注册中心的应用名称private final static String SERVER_IP_PORT = "http://MICROSERVICE-STUDENT";
上面配置好后,我们可以测试下;
先启动三个eureka,然后再启动服务提供者,再启动服务消费者 执行 http://localhost/student/list 结果就出来了,说明配置OK;前面搭建了初步例子,但是还没实现真正负载均衡,我们这里要先搞三个服务提供者集群,然后才能演示负载均衡,以及负载均衡策略;
按照它microservice-student-provider-1001建立一个microservice-student-provider子项目,然后将microservice-student-provider-1001这个子项目干掉; pom.xml,application.yml,以及java类都复制一份,启动类名称对应的改下; 启动类package com.zxp.microservicestudentprovider;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.autoconfigure.domain.EntityScan;import org.springframework.cloud.netflix.eureka.EnableEurekaClient;@EntityScan("com.zxp.*.*")@EnableEurekaClient@SpringBootApplicationpublic class MicroserviceStudentProviderApplication { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentProviderApplication.class, args); }}
application.yml
---server: port: 1001 context-path: /spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8 username: root password: 123 jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1001eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1001 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.zxp.com:2001/eureka/,http://eureka2002.zxp.com:2002/eureka/,http://eureka2003.zxp.com:2003/eureka/info: groupId: com.zxp.testSpringcloud artifactId: microservice-student-provider-1001 version: 1.0-SNAPSHOT userName: http://zxp.com phone: 123456---server: port: 1002 context-path: /spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8 username: root password: 123 jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1002eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1002 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.zxp.com:2001/eureka/,http://eureka2002.zxp.com:2002/eureka/,http://eureka2003.zxp.com:2003/eureka/info: groupId: com.zxp.testSpringcloud artifactId: microservice-student-provider-1002 version: 1.0-SNAPSHOT userName: http://zxp.com phone: 123456---server: port: 1003 context-path: /spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf8 username: root password: 123 jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1003eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1003 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.zxp.com:2001/eureka/,http://eureka2002.zxp.com:2002/eureka/,http://eureka2003.zxp.com:2003/eureka/info: groupId: com.zxp.testSpringcloud artifactId: microservice-student-provider-1003 version: 1.0-SNAPSHOT userName: http://zxp.com phone: 123456
yml配置文件有两处要对应的改下,port端口改下,以及服务实例名称改下;
StudentProviderController.java@Value("${server.port}") private String port; @RequestMapping("/ribbon") public String ribbon(){ return "工号【"+port+"】正在为您服务"; }
消费端80StudentConsumerController.java
@RequestMapping("/ribbon") public String ribbon(){ return restTemplate.getForObject(SERVER_IP_PORT + "/student/ribbon", String.class); }
测试
先测试服务提供者: http://localhost:1001/student/list http://localhost:1002/student/list http://localhost:1003/student/list 再测试下 eureka: http://eureka2001.zxp.com:2001/ 有这种的话,就说明没问题; 但是这种默认的轮询策略肯定是不能满足实际需求的,比如有3个服务提供者,突然挂了一个,这样的话,默认轮询 ,总有1/3的概率访问失败; 所以我们看下ribbon默认给我们提供的策略有哪些; 默认7个策略,根据具体产品需求,来选用;简介
声明式服务调用Feign简单介绍: Feign是一个声明式的Web Service客户端,它使得编写Web Serivce客户端变得更加简单。我们只需要使用Feign来创建一个接口并用注解来配置它既可完成。它具备可插拔的注解支持,包括Feign注解和JAX-RS注解。Feign也支持可插拔的编码器和解码器。Spring Cloud为Feign增加了对Spring MVC注解的支持,还整合了Ribbon和Eureka来提供均衡负载的HTTP客户端实现。这段话看起来比较懵逼,这里说下实际使用,前面Ribbon调用服务提供者,我们通过restTemplate调用,缺点是,多个地方调用,同一个请求要写多次,不方便统一维护,这时候Feign来了,就直接把请求统一搞一个service作为FeignClient,然后其他调用Controller需要用到的,直接注入service,直接调用service方法即可;同时Feign整合了Ribbon和Eureka,所以要配置负载均衡的话,直接配置Ribbon即可,无其他特殊地方;当然Fiegn也整合了服务容错保护,断路器Hystrix,后面再说。
解决宕机问题 服务消费端 SpringCloudConfig配置类添加 指定IRule实现; 这里我们演示用 RetryRule,大伙可以自行测试;/** * 自定义轮询算法 * @return */ @Bean public IRule myRule(){ return new RetryRule(); }
Feign应用
在common项目里建一个service(实际项目肯定是多个service)作为Feign客户端,用Feign客户端来调用服务器提供者,当然可以配置负载均衡;Feign客户端定义的目的,就是为了方便给其他项目调用; 修改 microservice-common pom.xml引入Feign依赖org.springframework.cloud spring-cloud-starter-feign
我们定义了 FeignClient,同时指定了调用的服务名称MICROSERVICE-STUDENT
common项目修改后,maven clean下 然后install下;建StudentClientService接口
package com.zxp.microservicecommon.service;import com.zxp.microservicecommon.entity.Student;import org.springframework.cloud.netflix.feign.FeignClient;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.PostMapping;import org.springframework.web.bind.annotation.RequestMapping;import java.util.List;/** * Student Feign接口客户端 * @author Administrator * */@FeignClient(value="MICROSERVICE-STUDENT")public interface StudentClientService { /** * 根据id查询学生信息 * @param id * @return */ @GetMapping(value="/student/get/{id}") public Student get(@PathVariable("id") Integer id); /** * 查询学生信息 * @return */ @GetMapping(value="/student/list") public Listlist(); /** * 添加或者修改学生信息 * @param student * @return */ @PostMapping(value="/student/save") public boolean save(Student student); /** * 根据id删除学生信息 * @return */ @GetMapping(value="/student/delete/{id}") public boolean delete(@PathVariable("id") Integer id); @RequestMapping("/student/ribbon") public String ribbon();}
新建一个Feign消费者项目
参考microservice-student-consumer-80建一个microservice-student-consumer-feign-80代码都复制一份,包括pom.xml修改启动类名称,和加注解
启动类名称改下,改成StudentConsumerFeignApplication_80,同时加个注解@EnableFeignClients(value = “com.zxp..”)支持下Feignpackage com.zxp.microservicestudentconsumerfeign80;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;import org.springframework.cloud.netflix.eureka.EnableEurekaClient;import org.springframework.cloud.netflix.feign.EnableFeignClients;@EnableEurekaClient@EnableFeignClients(value = "com.zxp.*.*")@SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})public class MicroserviceStudentConsumerFeign80Application { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentConsumerFeign80Application.class, args); }}
修改StudentConsumerController
因为现在用Fiegn,所以把restTemplate去掉,改成注入service,调用service方法来实现服务的调用;package com.zxp.microservicestudentconsumerfeign80.controller;import com.zxp.microservicecommon.entity.Student;import com.zxp.microservicecommon.service.StudentClientService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.*;import org.springframework.web.client.RestTemplate;import java.util.List;@RestController@RequestMapping("/student")public class StudentConsumerController { @Autowired private StudentClientService studentClientService; @Autowired private RestTemplate restTemplate; @PostMapping(value = "/save") private boolean save(Student student) { return studentClientService.save(student); } @GetMapping(value = "/list") public Listlist() { return studentClientService.list(); } @GetMapping(value = "/get/{id}") public Student get(@PathVariable("id") Integer id) { return studentClientService.get(id); } @GetMapping(value = "/delete/{id}") public boolean delete(@PathVariable("id") Integer id) { try { studentClientService.delete(id); return true; } catch (Exception e) { return false; } } @RequestMapping("/ribbon") public String ribbon(){ return studentClientService.ribbon(); }}
测试负载均衡
将服务1003号关闭转载地址:http://wyrzi.baihongyu.com/