SpringCloud之Ribbon负载均衡及Feign消费者调用服务
目的：
微服务调用Ribbon
Ribbon负载均衡
Feign简介及应用
微服务调用Ribbon
Ribbon简介
1. 负载均衡框架，支持可插拔式的负载均衡规则
2. 支持多种协议，如HTTP、UDP等
3. 提供负载均衡客户端
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（工程我是在上一篇博客中玩集成建成https://www.cnblogs.com/huangting/p/11902121.html）
首先，引入依赖，pom.xml 加入 ribbon相关依赖
<!--ribbon相关依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
给application.yml配置
server: port: 80 context-path: / eureka: client: service-url: defaultZone: http://eureka2001.ht.com:2001/eureka/,http://eureka2002.ht.com:2002/eureka/,http://eureka2003.ht.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 @LoadBalanced
因为和eureka整合，所以启动类StudentConsumerApplication_80 加个注解 @EnableEurekaClient
在提供者microservice-student-provider-1001的yml文件中添加配置：
application:
name: 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；
访问http://localhost/student/list
Ribbon负载均衡
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；
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；
新建项目microservice-student-provider-1002，microservice-student-provider-1003
pom.xml，application.yml，以及java类都复制一份，启动类名称对应的改下；
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；
pom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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>com.ht</groupId> <artifactId>htSpringCloud</artifactId> <version>1.0-SNAPSHOT</version> </parent> <groupId>com.ht</groupId> <artifactId>microservice-student-provider</artifactId> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> </dependency> <!-- 修改后立即生效，热部署 --> <dependency> <groupId>org.springframework</groupId> <artifactId>springloaded</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> </dependency> <!--添加注册中心Eureka相关配置--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> </dependency> <!-- actuator监控引入 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
配置Yml文件
--- 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: root jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1001 eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1001 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.ht.com:2001/eureka/,http://eureka2002.ht.com:2002/eureka/,http://eureka2003.ht.com:2003/eureka/ info: groupId: com.ht.htSpringCloud artifactId: microservice-student-provider-1001 version: 1.0-SNAPSHOT userName: http://ht.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: root jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1002 eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1002 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.ht.com:2001/eureka/,http://eureka2002.ht.com:2002/eureka/,http://eureka2003.ht.com:2003/eureka/ info: groupId: com.ht.htSpringCloud artifactId: microservice-student-provider-1002 version: 1.0-SNAPSHOT userName: http://ht.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: root jpa: hibernate: ddl-auto: update show-sql: true application: name: microservice-student profiles: provider-1003 eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1003 prefer-ip-address: true client: service-url: defaultZone: http://eureka2001.ht.com:2001/eureka/,http://eureka2002.ht.com:2002/eureka/,http://eureka2003.ht.com:2003/eureka/ info: groupId: com.ht.htSpringCloud artifactId: microservice-student-provider-1003 version: 1.0-SNAPSHOT userName: http://ht.com phone: 123456
启动类中添加注解
package com.ht.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.ht.*.*") @EnableEurekaClient @SpringBootApplication public class MicroserviceStudentProviderApplication { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentProviderApplication.class, args); } }
在消费者microservice-student-provider-80的controller中加：
@RequestMapping("/ribbon")
public String ribbon(){
return restTemplate.getForObject(SERVER_IP_PORT+"/student/ribbon/", String.class);
}
生产者microservice-student-providerd controller中加：
@Value("${server.port}")
private String port;
@RequestMapping("/ribbon")
public String ribbon(){
return "工号【"+port+"】正在为您服务";
}
我们启动服务后在浏览器中刷新地址
每刷新一次后台就会更改一次服务工号
假如有3个服务提供者，突然挂了一个，那么就会产生1/3的概率访问失败； 所以ribbon给我们提供了一个很好的插件。
在microservicestudentconsumer80的
SpringCloudConfig中 加：
/** * 自定义调用规则（服务提供者掉线后不再调用，解决轮询问题） * @return */ @Bean public IRule myRule(){ return new RetryRule(); // return new RandomRule(); }
Feign简介及应用
-
简介
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。
-
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：
<!--引入Feign依赖--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-feign</artifactId> </dependency>
创建StudentClientService接口：
package com.ht.microservicecommon; import com.ht.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 List<Student> list(); /** * 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
新项目中需要添加新pom依赖
<!--ribbon相关依赖--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-ribbon</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> </dependency> <!--引入Feign依赖--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-feign</artifactId> </dependency> </dependencies>
SpringCloudconig
package com.ht.microservicestudentconsumerfeign80.config; import com.netflix.loadbalancer.IRule; import com.netflix.loadbalancer.RandomRule; import com.netflix.loadbalancer.RetryRule; 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; @Configuration public class SpringCloudConfig { @LoadBalanced // 引入ribbon负载均衡 @Bean public RestTemplate getRestTemplate(){ return new RestTemplate(); } /** * 自定义调用规则（服务提供者掉线后不再调用，解决轮询问题） * @return */ @Bean public IRule myRule(){ return new RetryRule(); // return new RandomRule(); } }
Yml文件
server: port: 80 context-path: / eureka: client: service-url: defaultZone: http://eureka2001.ht.com:2001/eureka/,http://eureka2002.ht.com:2002/eureka/,http://eureka2003.ht.com:2003/eureka/ register-with-eureka: false
启动类中添加注释
package com.ht.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.ht.*.*") @SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class}) public class MicroserviceStudentConsumerFeign80Application { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentConsumerFeign80Application.class, args); } }
StudnetConsumerController
package com.javaxl.microservicestudentconsumerfeign80.controller; import com.ht.microservicecommon.StudentClientService; import com.ht.microservicecommon.entity.Student; 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 List<Student> list() { 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(); } }
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；
