SpringCloud微服务Ribbon负载均衡及Feign应用

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。

SpringCloud微服务Ribbon负载均衡及Feign应用
SpringCloud微服务Ribbon负载均衡及Feign应用

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

SpringCloud微服务Ribbon负载均衡及Feign应用
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
SpringCloud微服务Ribbon负载均衡及Feign应用
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;

SpringCloud微服务Ribbon负载均衡及Feign应用
SpringCloud微服务Ribbon负载均衡及Feign应用

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
SpringCloud微服务Ribbon负载均衡及Feign应用
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);
    }

SpringCloud微服务Ribbon负载均衡及Feign应用
SpringCloud微服务Ribbon负载均衡及Feign应用
SpringCloud微服务Ribbon负载均衡及Feign应用

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;
SpringCloud微服务Ribbon负载均衡及Feign应用

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