SpringCloud微服务Ribbon负载均衡及Feign应用
微服务调用Ribbon
简介
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；
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
<!--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>
application.yml加
server:
port: 80
context-path: /
eureka:
client:
service-url:
defaultZone: http://eureka2001.liuchunming.com:2001/eureka/,http://eureka2002.liuchunming.com:2002/eureka/,http://eureka2003.liuchunming.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
package com.liuchunming.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;
@Configuration
public 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.liuchunming.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;
@EnableEurekaClient
@SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
public class MicroserviceStudentConsumer80Application {
public static void main(String[] args) {
SpringApplication.run(MicroserviceStudentConsumer80Application.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
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；
结果就出来了，说明配置OK；
Ribbon负载均衡
按照它microservice-student-provider-1001建立一个microservice-student-provider项目。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；
创建microservice-student-provider项目
相关代码如下
相关pom
<?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.liuchunming</groupId>
<artifactId>t243microservice</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<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>
<dependency>
<groupId>com.liuchunming</groupId>
<artifactId>microservice-common</artifactId>
<version>1.0-SNAPSHOT</version>
<scope>compile</scope>
</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>
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/liuchunming?useUnicode=true&characterEncoding=utf8
username: root
password: 123
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.liuchunming.com:2001/eureka/,http://eureka2002.liuchunming.com:2002/eureka/,http://eureka2003.liuchunming.com:2003/eureka/
info:
groupId: com.liuchunming.testSpringcloud
artifactId: microservice-student-provider-1001
version: 1.0-SNAPSHOT
userName: http://liuchunming.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/liuchunming?useUnicode=true&characterEncoding=utf8
username: root
password: 123
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.liuchunming.com:2001/eureka/,http://eureka2002.liuchunming.com:2002/eureka/,http://eureka2003.liuchunming.com:2003/eureka/
info:
groupId: com.liuchunming.testSpringcloud
artifactId: microservice-student-provider-1002
version: 1.0-SNAPSHOT
userName: http://liuchunming.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/liuchunming?useUnicode=true&characterEncoding=utf8
username: root
password: 123
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.liuchunming.com:2001/eureka/,http://eureka2002.liuchunming.com:2002/eureka/,http://eureka2003.liuchunming.com:2003/eureka/
info:
groupId: com.liuchunming.testSpringcloud
artifactId: microservice-student-provider-1003
version: 1.0-SNAPSHOT
userName: http://liuchunming.com
phone: 123456
启动类
package com.liuchunming.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.liuchunming.*.*")
@EnableEurekaClient
@SpringBootApplication
public class MicroserviceStudentProviderApplication {
public static void main(String[] args) {
SpringApplication.run(MicroserviceStudentProviderApplication.class, args);
}
}
StudentProviderController.java
@Value("${server.port}")
private String port;
@RequestMapping("/ribbon")
public String ribbon(){
return "工号【"+port+"】正在为您服务";
}
在student-consumer-80的StudentConsumerController.java添加
@RequestMapping("/ribbon")
public String ribbon() {
return restTemplate.getForObject(SERVER_IP_PORT + "/student/ribbon", String.class);
}
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；
| 策略名 | 策略声明 |
|---|---|
| BestAvailableRule | public class BestAvailableRule extends ClientConfigEnabledRoundRobinRule |
| AvailabilityFilteringRule | public class AvailabilityFilteringRule extends PredicateBasedRule |
| WeightedResponseTimeRule | public class WeightedResponseTimeRule extends RoundRobinRule |
| RetryRule | public class RetryRule extends AbstractLoadBalancerRule |
| RoundRobinRule | public class RoundRobinRule extends AbstractLoadBalancerRule |
| RandomRule | public class RandomRule extends AbstractLoadBalancerRule |
| ZoneAvoidanceRule | public class ZoneAvoidanceRule extends PredicateBasedRule |
默认7个策略，根据具体产品需求，我们选用；
服务消费端 SpringCloudConfig配置类
/**
* 自定义轮询算法
* @return
*/
@Bean
public IRule myRule(){
return new RetryRule();
}
Feign简介及应用
简介
声明式服务调用Feign简单介绍下；
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
1、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
<!--引入Feign依赖-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
建StudentClientService接口；
package com.liuchunming.microservicecommon.service;
import com.liuchunming.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();
}
2、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
<?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.liuchunming</groupId>
<artifactId>t243microservice</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<artifactId>microservice-student-consumer-feign-80</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>
<!-- 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>
<dependency>
<groupId>com.liuchunming</groupId>
<artifactId>microservice-common</artifactId>
<version>1.0-SNAPSHOT</version>
<scope>compile</scope>
</dependency>
<!--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>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
SpringCloudConfig.java
package com.liuchunming.microservicestudentconsumerfeign80.config;
import com.netflix.loadbalancer.IRule;
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.liuchunming.com:2001/eureka/,http://eureka2002.liuchunming.com:2002/eureka/,http://eureka2003.liuchunming.com:2003/eureka/
register-with-eureka: false
3、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
支持下Feign；
package com.liuchunming.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.liuchunming.*.*")
@SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class})
public class MicroserviceStudentConsumerFeign80Application {
public static void main(String[] args) {
SpringApplication.run(MicroserviceStudentConsumerFeign80Application.class, args);
}
}
StudentConsumerController.java
package com.liuchunming.microservicestudentconsumerfeign80.controller;
import com.liuchunming.microservicecommon.entity.Student;
import com.liuchunming.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 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；
5、测试负载均衡；